cURL

curl --request POST \
  --url https://api.nano-gpt.com/api/v1/responses \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "<string>",
  "input": "<string>",
  "billing_mode": "<string>",
  "billingMode": "<string>",
  "instructions": "<string>",
  "max_output_tokens": 17,
  "temperature": 1,
  "top_p": 0.5,
  "tools": [
    {
      "max_results": 5
    }
  ],
  "tool_choice": "<string>",
  "parallel_tool_calls": true,
  "stream": false,
  "store": false,
  "retention_days": 182,
  "retentionDays": 182,
  "previous_response_id": "<string>",
  "reasoning": {},
  "text": {},
  "metadata": {},
  "user": "<string>",
  "seed": 123,
  "background": true
}
'

import requests

url = "https://api.nano-gpt.com/api/v1/responses"

payload = {
    "model": "<string>",
    "input": "<string>",
    "billing_mode": "<string>",
    "billingMode": "<string>",
    "instructions": "<string>",
    "max_output_tokens": 17,
    "temperature": 1,
    "top_p": 0.5,
    "tools": [{ "max_results": 5 }],
    "tool_choice": "<string>",
    "parallel_tool_calls": True,
    "stream": False,
    "store": False,
    "retention_days": 182,
    "retentionDays": 182,
    "previous_response_id": "<string>",
    "reasoning": {},
    "text": {},
    "metadata": {},
    "user": "<string>",
    "seed": 123,
    "background": True
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: '<string>',
    input: '<string>',
    billing_mode: '<string>',
    billingMode: '<string>',
    instructions: '<string>',
    max_output_tokens: 17,
    temperature: 1,
    top_p: 0.5,
    tools: [{max_results: 5}],
    tool_choice: '<string>',
    parallel_tool_calls: true,
    stream: false,
    store: false,
    retention_days: 182,
    retentionDays: 182,
    previous_response_id: '<string>',
    reasoning: {},
    text: {},
    metadata: {},
    user: '<string>',
    seed: 123,
    background: true
  })
};

fetch('https://api.nano-gpt.com/api/v1/responses', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nano-gpt.com/api/v1/responses",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => '<string>',
    'input' => '<string>',
    'billing_mode' => '<string>',
    'billingMode' => '<string>',
    'instructions' => '<string>',
    'max_output_tokens' => 17,
    'temperature' => 1,
    'top_p' => 0.5,
    'tools' => [
        [
                'max_results' => 5
        ]
    ],
    'tool_choice' => '<string>',
    'parallel_tool_calls' => true,
    'stream' => false,
    'store' => false,
    'retention_days' => 182,
    'retentionDays' => 182,
    'previous_response_id' => '<string>',
    'reasoning' => [
        
    ],
    'text' => [
        
    ],
    'metadata' => [
        
    ],
    'user' => '<string>',
    'seed' => 123,
    'background' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.nano-gpt.com/api/v1/responses"

	payload := strings.NewReader("{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.nano-gpt.com/api/v1/responses")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.nano-gpt.com/api/v1/responses")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "object": "<string>",
  "created_at": 123,
  "model": "<string>",
  "status": "queued",
  "output": [
    {}
  ],
  "output_text": "<string>",
  "usage": {},
  "error": {},
  "incomplete_details": {},
  "metadata": {},
  "service_tier": "<string>",
  "advisor": {
    "id": "<string>",
    "mode": "auto",
    "executor_model": "<string>",
    "advisor_model": "<string>",
    "requested": true,
    "consulted": true,
    "successful": true,
    "consultation_count": 0,
    "max_uses": 1,
    "status": "not_used",
    "error": "<string>",
    "usage": {
      "executor": {},
      "advisor": {},
      "continuation": {},
      "total": {}
    },
    "pricing": {
      "executor": {},
      "advisor": {},
      "continuation": {},
      "total": {}
    }
  }
}

{
  "error": 123,
  "message": "<string>"
}

{
  "error": 123,
  "message": "<string>"
}

{
  "error": 123,
  "message": "<string>"
}

Endpoint Examples

Responses

Create a response with the OpenAI-compatible Responses API. Compatible models can use the Responses-only hosted tool-search pilot by adding a nanogpt:tool_search or tool_search entry and marking function tools with defer_loading: true. The NanoGPT Advisor extension is available for non-streaming, foreground, platform-billed pay-as-you-go API-key requests that do not use client tools, structured output, inline moderation, BYOK, accountless payment, memory, or server-side content enhancements.

POST

responses

cURL

curl --request POST \
  --url https://api.nano-gpt.com/api/v1/responses \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "<string>",
  "input": "<string>",
  "billing_mode": "<string>",
  "billingMode": "<string>",
  "instructions": "<string>",
  "max_output_tokens": 17,
  "temperature": 1,
  "top_p": 0.5,
  "tools": [
    {
      "max_results": 5
    }
  ],
  "tool_choice": "<string>",
  "parallel_tool_calls": true,
  "stream": false,
  "store": false,
  "retention_days": 182,
  "retentionDays": 182,
  "previous_response_id": "<string>",
  "reasoning": {},
  "text": {},
  "metadata": {},
  "user": "<string>",
  "seed": 123,
  "background": true
}
'

import requests

url = "https://api.nano-gpt.com/api/v1/responses"

payload = {
    "model": "<string>",
    "input": "<string>",
    "billing_mode": "<string>",
    "billingMode": "<string>",
    "instructions": "<string>",
    "max_output_tokens": 17,
    "temperature": 1,
    "top_p": 0.5,
    "tools": [{ "max_results": 5 }],
    "tool_choice": "<string>",
    "parallel_tool_calls": True,
    "stream": False,
    "store": False,
    "retention_days": 182,
    "retentionDays": 182,
    "previous_response_id": "<string>",
    "reasoning": {},
    "text": {},
    "metadata": {},
    "user": "<string>",
    "seed": 123,
    "background": True
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: '<string>',
    input: '<string>',
    billing_mode: '<string>',
    billingMode: '<string>',
    instructions: '<string>',
    max_output_tokens: 17,
    temperature: 1,
    top_p: 0.5,
    tools: [{max_results: 5}],
    tool_choice: '<string>',
    parallel_tool_calls: true,
    stream: false,
    store: false,
    retention_days: 182,
    retentionDays: 182,
    previous_response_id: '<string>',
    reasoning: {},
    text: {},
    metadata: {},
    user: '<string>',
    seed: 123,
    background: true
  })
};

fetch('https://api.nano-gpt.com/api/v1/responses', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.nano-gpt.com/api/v1/responses",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => '<string>',
    'input' => '<string>',
    'billing_mode' => '<string>',
    'billingMode' => '<string>',
    'instructions' => '<string>',
    'max_output_tokens' => 17,
    'temperature' => 1,
    'top_p' => 0.5,
    'tools' => [
        [
                'max_results' => 5
        ]
    ],
    'tool_choice' => '<string>',
    'parallel_tool_calls' => true,
    'stream' => false,
    'store' => false,
    'retention_days' => 182,
    'retentionDays' => 182,
    'previous_response_id' => '<string>',
    'reasoning' => [
        
    ],
    'text' => [
        
    ],
    'metadata' => [
        
    ],
    'user' => '<string>',
    'seed' => 123,
    'background' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.nano-gpt.com/api/v1/responses"

	payload := strings.NewReader("{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.nano-gpt.com/api/v1/responses")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.nano-gpt.com/api/v1/responses")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"<string>\",\n  \"input\": \"<string>\",\n  \"billing_mode\": \"<string>\",\n  \"billingMode\": \"<string>\",\n  \"instructions\": \"<string>\",\n  \"max_output_tokens\": 17,\n  \"temperature\": 1,\n  \"top_p\": 0.5,\n  \"tools\": [\n    {\n      \"max_results\": 5\n    }\n  ],\n  \"tool_choice\": \"<string>\",\n  \"parallel_tool_calls\": true,\n  \"stream\": false,\n  \"store\": false,\n  \"retention_days\": 182,\n  \"retentionDays\": 182,\n  \"previous_response_id\": \"<string>\",\n  \"reasoning\": {},\n  \"text\": {},\n  \"metadata\": {},\n  \"user\": \"<string>\",\n  \"seed\": 123,\n  \"background\": true\n}"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "object": "<string>",
  "created_at": 123,
  "model": "<string>",
  "status": "queued",
  "output": [
    {}
  ],
  "output_text": "<string>",
  "usage": {},
  "error": {},
  "incomplete_details": {},
  "metadata": {},
  "service_tier": "<string>",
  "advisor": {
    "id": "<string>",
    "mode": "auto",
    "executor_model": "<string>",
    "advisor_model": "<string>",
    "requested": true,
    "consulted": true,
    "successful": true,
    "consultation_count": 0,
    "max_uses": 1,
    "status": "not_used",
    "error": "<string>",
    "usage": {
      "executor": {},
      "advisor": {},
      "continuation": {},
      "total": {}
    },
    "pricing": {
      "executor": {},
      "advisor": {},
      "continuation": {},
      "total": {}
    }
  }
}

{
  "error": 123,
  "message": "<string>"
}

{
  "error": 123,
  "message": "<string>"
}

{
  "error": 123,
  "message": "<string>"
}

/v1/responses accepts compressed request bodies (Content-Encoding: gzip, deflate, or br) on authenticated JSON requests — useful for long conversations, where compressed uploads cut time-to-first-token. See Compressed Request Bodies.

Overview

The /v1/responses API is an OpenAI Responses API-compatible endpoint for creating AI model responses. It supports:

Stateless and stateful (conversation threading) chat completions
Streaming responses via Server-Sent Events (SSE)
Background (async) processing for long-running requests
Response storage and retrieval
Function/tool calling support
Multimodal inputs (images, video, files) for supported models

Recommended base URL: Use https://api.nano-gpt.com/api/v1 for Responses API clients. This dedicated API host accepts request bodies up to NanoGPT’s 32 MiB application limit and avoids the smaller ingress limit on the website host. It is especially important for Codex and other long-running agents that resend accumulated conversation state.

Accountless x402 payments: Non-streaming POST /api/v1/responses requests can be quoted without an account or API key on supported deployments when the initial quote request includes x-x402: true. Streaming and background Responses have implementation coverage but are not part of the stable public accountless contract. This endpoint supports accountless x402 payments where listed by GET /api/v1/x402/endpoints, including Lightning L402 when advertised. See Accountless x402 API Payments for the full flow.

Provider selection is available for supported open-source models. X-Provider explicitly selects a provider for the request and is always billed pay-as-you-go at the selected provider’s price, including provider-selection markup. For provider-selection-capable models, model may include routing preference suffixes such as :fast (alias for :speed) and :cheap (alias for :price). These are billed like explicit provider selection and follow the same conflict rules. For subscription users, sending X-Provider bypasses subscription coverage for that request; X-Billing-Mode: paygo is only needed when forcing pay-as-you-go without an explicit provider or when saved provider preferences should apply to subscription-included traffic. See Provider Selection, Model Suffixes, and Pay-As-You-Go Billing Override.

Advisor extension: Non-streaming pay-as-you-go API-key requests can include an advisor object so the executor model can consult one different model before returning its final answer. Use mode: "auto" to let the executor decide or mode: "required" to require a consultation attempt. Each completed model phase is billed separately. Advisor is a NanoGPT extension, not part of the standard OpenAI request schema. See Advisor.

Hosted tool search: Compatible models can discover relevant functions from large deferred catalogs. Add nanogpt:tool_search and mark functions with defer_loading: true. This pilot is Responses-only. See Hosted tool search.

Authentication

Use an API key for normal authenticated billing:

Authorization: Bearer YOUR_API_KEY

Or alternatively:

x-api-key: YOUR_API_KEY

For API-key requests, you can optionally pass x-team-id to choose team context when team defaults are evaluated (for example, retention defaults). For supported accountless x402 requests, omit Authorization and x-api-key, and include x-x402: true to receive a payment quote. The advertised schemes, including Lightning L402 when enabled, are listed by GET /api/v1/x402/endpoints. If you receive 401 missing_api_key immediately, check that the initial quote request includes x-x402: true. Without that header, NanoGPT does not enter the x402 quote flow.

Endpoints

POST /v1/responses - Create a new response from the model
GET /v1/responses - Returns endpoint information
GET /v1/responses/{id} - Retrieve a stored response by ID
DELETE /v1/responses/{id} - Delete a stored response (soft delete)

Batch processing

For high-volume work that does not need an immediate response, /v1/responses requests can be submitted through the Batch API. Responses batches are non-streaming, stateless, use direct OpenAI models, and run with store: false. Function and custom tools, structured text output, and remote or data-URL images are supported; video input remains unsupported in Responses Batch. Stateful features, provider-hosted tools, file references, and NanoGPT-only request extensions are not.

BYOK Encryption (Stored Responses)

If you set store: true, you can optionally encrypt the stored response at rest using your own key or passphrase. To encrypt a stored response, include one of these headers on POST /v1/responses:

x-encryption-key: YOUR_ENCRYPTION_KEY
x-encryption-passphrase: YOUR_PASSPHRASE

When retrieving or deleting an encrypted response, include the same header you used at creation time. Example:

# Create an encrypted, stored response
curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "x-encryption-key: YOUR_ENCRYPTION_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "Sensitive information",
    "store": true
  }'

# Retrieve it later (must include the same encryption header)
curl https://api.nano-gpt.com/api/v1/responses/resp_abc123 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "x-encryption-key: YOUR_ENCRYPTION_KEY"

Create Response

Request

POST /v1/responses
Content-Type: application/json
Authorization: Bearer YOUR_API_KEY

Request Body

Parameter	Type	Required	Description
`model`	string	Yes	Model ID to use for the response. Provider-selection-capable models may include routing preference suffixes such as `:fast`, `:speed`, `:cheap`, `:price`, `:latency`, `:throughput`, `:floor`, `:tools`, `:caching`, `:cache`, or `:cached`.
`input`	string or array	Yes	The input prompt or array of input items
`advisor`	object	No	NanoGPT extension that lets the executor consult one different, client-selected model. Initially limited to non-streaming, pay-as-you-go API-key requests. See Advisor.
`instructions`	string	No	System instructions for the model
`max_output_tokens`	integer	No	Maximum tokens in the response (minimum: 16)
`max_tool_calls`	integer	No	Maximum number of tool calls allowed
`temperature`	number	No	Sampling temperature (0-2). If omitted, NanoGPT does not force a value and the routed provider/model default applies (OpenAI defaults to 1.0). Not supported by reasoning-capable models
`top_p`	number	No	Nucleus sampling parameter. Not supported by reasoning-capable models
`presence_penalty`	number	No	Presence penalty for sampling (-2.0 to 2.0)
`frequency_penalty`	number	No	Frequency penalty for sampling (-2.0 to 2.0)
`top_logprobs`	integer	No	Number of top logprobs to return (0-20)
`tools`	array	No	Array of tools available to the model. Compatible models can use hosted tool search with deferred function definitions.
`tool_choice`	string or object	No	Tool use: `auto`, `none`, `required`, `{ type: "function", name: "..." }`, or `{ type: "allowed_tools", ... }`
`parallel_tool_calls`	boolean	No	Allow multiple tool calls in parallel
`stream`	boolean	No	Enable streaming responses (default: false)
`stream_options`	object	No	Streaming options: `{ include_obfuscation?: boolean }`
`store`	boolean	No	Store the response locally for later retrieval/threading/background processing. Set `false` to disable stored Responses API data for the request.
`retention_days`	integer or null	No	Per-request retention override in days (`0..365`). `null` means no request-level override
`retentionDays`	integer or null	No	Alias for `retention_days`. If both are sent, values must match
`previous_response_id`	string	No	Link to previous response for conversation threading
`reasoning`	object	No	Reasoning configuration. Setting `reasoning.effort` to any non-`none` value explicitly requests reasoning mode.
`text`	object	No	Text output configuration (format + verbosity)
`metadata`	object	No	Custom metadata (max 16 keys, 64 char keys, 512 char values)
`truncation`	string	No	Truncation strategy: `auto` or `disabled`
`user`	string	No	Unique user identifier
`seed`	integer	No	Optional integer forwarded on model/provider routes that support seeded sampling. This may improve reproducibility but does not guarantee identical output. Results can change if NanoGPT selects a different automatic or fallback route, or if the provider changes its backend.
`conversation`	object	No	Conversation context: `{ id?: string, messages?: InputItem[] }`
`include`	string[]	No	Additional fields to include in response
`safety_identifier`	string	No	Safety tracking identifier
`prompt_cache_key`	string	No	Key for prompt caching
`background`	boolean	No	Enable background/async processing
`service_tier`	string	No	Service tier: `"auto"`, `"default"`, `"flex"`, or `"priority"`. See Service tiers (flex and priority) near the end.

Reproducibility guidance

Seeded generation is best-effort. To reduce avoidable variation:

Keep the exact model, input, instructions, tools, and sampling settings unchanged.
Select a specific provider where possible.
Disable automatic fallbacks where supported when route consistency matters.
Use a low or zero temperature where supported.
Do not treat seeded output as byte-identical. Record provider, route, and system-fingerprint metadata when NanoGPT exposes reliable values.

NanoGPT will publish a seed-support matrix when reliable route-level capability data is available. Until then, do not infer seed support from endpoint compatibility alone.

Response Storage And Retention

NanoGPT supports local Responses API storage for features that need server-side state, including response retrieval, previous_response_id threading, and background processing. Set store: false to disable stored Responses API data for a request:

{
  "model": "gpt-5.2",
  "input": "Hello",
  "store": false
}

When response storage is enabled and no override applies, stored Responses API records are retained for up to 7 days. You can override retention per request with either retentionDays or retention_days:

{
  "model": "gpt-5.2",
  "input": "Hello",
  "store": true,
  "retentionDays": 3
}

or:

{
  "model": "gpt-5.2",
  "input": "Hello",
  "store": true,
  "retention_days": 3
}

A retention value of 0 means do not retain stored response data for that request:

{
  "model": "gpt-5.2",
  "input": "Hello",
  "store": true,
  "retentionDays": 0
}

Valid per-request retention values are integers from 0 to 365 days, or null to use the next configured default. If both retentionDays and retention_days are sent, they must match. Team and user defaults are configurable through API endpoints, not the main web Settings page today. Team owners/admins can set responses_retention_days with PATCH /api/teams/{teamUuid}/settings; users can set responsesRetentionDays with POST /api/user/responses-retention. See Teams: response retention defaults.

Retention Resolution

Effective retention for /v1/responses resolves in this order:

Request override (retention_days / retentionDays)
Team setting (responses_retention_days)
User setting (responsesRetentionDays)
Platform default (7 days)

Rules:

retention_days and retentionDays accept integer values 0..365, or null.
null means “no request override” and falls back to team/user/platform defaults.
If both request fields are provided, they must match.
Invalid retention values return 400 with invalid_request_error.
0 enables zero-retention behavior for that request.
Existing clients that omit retention fields keep default behavior (team/user/platform retention resolution).

With effective retention 0:

previous_response_id is rejected.
background is rejected.

API-key team context for retention defaults:

If x-team-id is present and the caller is a member, that team is used.
Otherwise, the API uses the caller session’s default team (default_team_uuid / default_team_id) when membership is valid.

Input Types

The input parameter accepts either a simple string or an array of input items.

Simple String Input

{
  "model": "openai/gpt-5.6-sol",
  "input": "What is the capital of France?"
}

Array Input

{
  "model": "openai/gpt-5.6-sol",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": "What is the capital of France?"
    }
  ]
}

Input Item Types

Type	Description
`message`	A message with role and content
`function_call`	A tool/function call made by the model
`function_call_output`	The result of a tool/function call

Message Item

{
  "type": "message",
  "role": "user",
  "content": "Hello, how are you?"
}

Supported roles: user, assistant, system, developer Content can be a string or an array of content parts:

{
  "type": "message",
  "role": "user",
  "content": [
    { "type": "input_text", "text": "What's in this image?" },
    { "type": "input_image", "image_url": "https://example.com/image.jpg" }
  ]
}

Content Part Types

Type	Description
`input_text`	Text input
`input_image`	Image input (via URL or file_id)
`input_video`	Video input (via HTTPS URL or video data URL)
`input_file`	File input
`output_text`	Text output (includes annotations/logprobs)
`refusal`	Model refusal

Image Input

{
  "type": "input_image",
  "image_url": "https://example.com/image.jpg",
  "detail": "auto"
}

The detail parameter can be: auto, low, or high.

Video Input

Use input_video for video understanding on a model that advertises video input:

{
  "model": "google/gemini-3.1-flash-lite",
  "input": [{
    "type": "message",
    "role": "user",
    "content": [
      { "type": "input_text", "text": "Summarize the action." },
      {
        "type": "input_video",
        "video_url": "data:video/mp4;base64,AAAA..."
      }
    ]
  }]
}

video_url may be a public HTTPS URL or a valid data:video/*;base64,... URL. Chat-style video_url content parts are accepted as a compatibility alias, but input_video is the canonical Responses shape. input_file is treated as video only when NanoGPT can safely identify it from a video/* MIME type, video data URL, or recognized video filename/URL extension. PDFs, audio files, and unknown or opaque files are not silently treated as video. An opaque file_id is not resolved for Responses video input; it returns video_file_id_not_supported. Video is currently rejected in Responses Batch. Segment offsets are validated but no current public text-model route can honor them; valid offsets return video_segment_not_supported.

Function Call Item

{
  "type": "function_call",
  "id": "fc_123",
  "call_id": "call_abc123",
  "name": "get_weather",
  "arguments": "{\"location\": \"Paris\"}"
}

Function Call Output Item

{
  "type": "function_call_output",
  "call_id": "call_abc123",
  "output": "{\"temperature\": 22, \"condition\": \"sunny\"}"
}

Tools

Provide function tools and built-in tools the model can use:

Function Tool

Define functions that the model can call:

{
  "model": "openai/gpt-5.6-sol",
  "input": "What's the weather in Paris?",
  "tools": [
    {
      "type": "function",
      "name": "get_weather",
      "description": "Get current weather for a location",
      "parameters": {
        "type": "object",
        "properties": {
          "location": {
            "type": "string",
            "description": "City name"
          }
        },
        "required": ["location"]
      },
      "strict": false
    }
  ],
  "tool_choice": "auto"
}

Hosted Tool Search

For large function catalogs, add one nanogpt:tool_search entry (or its tool_search alias) and mark discoverable functions with defer_loading: true:

{
  "model": "openai/gpt-5.5",
  "input": "Find the weather in Amsterdam",
  "tools": [
    { "type": "nanogpt:tool_search", "max_results": 5 },
    {
      "type": "function",
      "name": "weather_forecast",
      "description": "Get the weather forecast for a city",
      "parameters": {
        "type": "object",
        "properties": { "city": { "type": "string" } },
        "required": ["city"]
      },
      "defer_loading": true
    }
  ],
  "tool_choice": "auto"
}

The search activity is returned as tool_search_call. A selected function is still returned as a normal function_call; your client executes it and sends function_call_output. See Hosted tool search for limits, billing, authorization, and compatibility.

Web Search Tool

{
  "type": "web_search_preview",
  "search_context_size": "low",
  "user_location": {
    "type": "approximate",
    "country": "US",
    "city": "San Francisco",
    "region": "California"
  }
}

File Search Tool

{
  "type": "file_search",
  "vector_store_ids": ["vs_..."],
  "max_num_results": 10,
  "ranking_options": {
    "ranker": "auto",
    "score_threshold": 0.5
  }
}

Code Interpreter Tool

{
  "type": "code_interpreter",
  "container": { "type": "auto" }
}

MCP Tool

{
  "type": "mcp",
  "server_label": "my-server",
  "server_url": "https://...",
  "headers": { "Authorization": "Bearer ..." },
  "require_approval": "auto"
}

Image Generation Tool

{
  "type": "image_generation"
}

Tool Choice

Use allowed_tools to restrict which tools the model may choose from:

{
  "tool_choice": {
    "type": "allowed_tools",
    "tools": [{ "type": "function", "name": "get_weather" }],
    "mode": "auto"
  }
}

Function Tool Normalization

Function tools in responses always include nullable fields:

{
  "type": "function",
  "name": "get_weather",
  "description": null,
  "parameters": null,
  "strict": null
}

Reasoning Configuration

Use reasoning to control depth and visibility of reasoning output:

{
  "model": "anthropic/claude-opus-4.5",
  "input": "Solve this complex problem...",
  "reasoning": {
    "effort": "high",
    "summary": "auto"
  }
}

Parameter	Values	Description
`effort`	`none`, `minimal`, `low`, `medium`, `high`, `xhigh`	Reasoning depth. Any value other than `none` explicitly requests reasoning mode.
`summary`	`none`, `auto`, `detailed`, `concise`	Reasoning summary format
`exclude`	`true`, `false`	Controls output visibility (hides reasoning fields/blocks). It does not inherently disable reasoning compute.

Text/Format Configuration

Control response format and verbosity:

{
  "model": "openai/gpt-5.6-sol",
  "input": "List 3 colors",
  "text": {
    "format": { "type": "json_object" },
    "verbosity": "medium"
  }
}

Text Parameter Structure

{
  "format": { "type": "text" } | { "type": "json_object" } | { "type": "json_schema", "json_schema": { ... } },
  "verbosity": "low" | "medium" | "high"
}

Format Types

{ "type": "text" } - Plain text (default)
{ "type": "json_object" } - JSON object output
{ "type": "json_schema", "json_schema": { ... } } - Structured JSON with schema

Verbosity Values

low - Short, compact responses
medium - Balanced detail
high - Most detailed output

JSON Schema Format

{
  "text": {
    "format": {
      "type": "json_schema",
      "json_schema": {
        "name": "color_list",
        "schema": {
          "type": "object",
          "properties": {
            "colors": {
              "type": "array",
              "items": { "type": "string" }
            }
          }
        },
        "strict": true
      }
    }
  }
}

Response Format

Successful Response

{
  "id": "resp_abc123",
  "object": "response",
  "created_at": 1699000000,
  "completed_at": 1699000001,
  "model": "openai/gpt-5.6-sol",
  "status": "completed",
  "instructions": null,
  "previous_response_id": null,
  "tools": [],
  "tool_choice": "auto",
  "parallel_tool_calls": false,
  "truncation": "disabled",
  "text": {
    "format": { "type": "text" },
    "verbosity": "medium"
  },
  "reasoning": null,
  "temperature": 1,
  "top_p": 1,
  "presence_penalty": 0,
  "frequency_penalty": 0,
  "top_logprobs": 0,
  "max_output_tokens": null,
  "max_tool_calls": null,
  "user": null,
  "store": true,
  "background": false,
  "safety_identifier": null,
  "prompt_cache_key": null,
  "output": [
    {
      "type": "message",
      "id": "msg_xyz789",
      "role": "assistant",
      "status": "completed",
      "content": [
        {
          "type": "output_text",
          "text": "The capital of France is Paris.",
          "annotations": [],
          "logprobs": []
        }
      ]
    }
  ],
  "output_text": "The capital of France is Paris.",
  "usage": {
    "input_tokens": 15,
    "output_tokens": 10,
    "total_tokens": 25,
    "input_tokens_details": { "cached_tokens": 0 },
    "output_tokens_details": { "reasoning_tokens": 0 }
  },
  "metadata": {},
  "service_tier": "auto"
}

Response Fields

All fields below are always present; nullable values indicate an option was not set.

Field	Type	Description
`id`	string	Unique response identifier (format: `resp_*`)
`object`	string	Always `"response"`
`created_at`	integer	Unix timestamp of creation
`completed_at`	integer or null	Unix timestamp when response completed
`model`	string	Model used for the response
`status`	string	Response status
`instructions`	string or null	System instructions used
`previous_response_id`	string or null	ID of previous response in conversation
`tools`	array	Tools available (normalized with nullable fields)
`tool_choice`	string or object	Tool choice setting used
`parallel_tool_calls`	boolean	Whether parallel tool calls were enabled
`truncation`	string	Truncation strategy: `auto` or `disabled`
`text`	object	Resolved text configuration
`reasoning`	object or null	Reasoning configuration
`temperature`	number	Temperature used
`top_p`	number	Top-p value used
`presence_penalty`	number	Presence penalty used
`frequency_penalty`	number	Frequency penalty used
`top_logprobs`	number	Top logprobs setting
`max_output_tokens`	integer or null	Max output tokens setting
`max_tool_calls`	integer or null	Max tool calls setting
`user`	string or null	User identifier
`store`	boolean	Whether response was stored
`background`	boolean	Whether processed in background
`safety_identifier`	string or null	Safety identifier
`prompt_cache_key`	string or null	Prompt cache key
`output`	array	Array of output items
`output_text`	string	Convenience field with concatenated text output
`usage`	object	Token usage statistics
`error`	object	Error details (if status is `failed`)
`incomplete_details`	object	Details if status is `incomplete`
`metadata`	object	Custom metadata (if provided)
`service_tier`	string	Service tier used (echoed when provided)

Usage Object

The usage object always includes token details:

{
  "input_tokens": 100,
  "output_tokens": 50,
  "total_tokens": 150,
  "input_tokens_details": {
    "cached_tokens": 0
  },
  "output_tokens_details": {
    "reasoning_tokens": 0
  }
}

Response Status Values

Status	Description
`queued`	Background request is queued
`in_progress`	Request is being processed
`completed`	Request completed successfully
`incomplete`	Response was truncated
`failed`	Request failed with error
`cancelled`	Request was cancelled

`reasoning` Response Field

{
  "effort": "none" | "minimal" | "low" | "medium" | "high" | "xhigh" | null,
  "summary": "none" | "auto" | "detailed" | "concise" | null
}

`text` Response Field (Resolved)

{
  "format": { "type": "text" | "json_object" | "json_schema", "...": "..." },
  "verbosity": "low" | "medium" | "high" | undefined
}

Output Item Types

All output items include a status field.

Message Output

{
  "type": "message",
  "id": "msg_123",
  "role": "assistant",
  "status": "completed",
  "content": [
    {
      "type": "output_text",
      "text": "Response text here",
      "annotations": [],
      "logprobs": []
    }
  ]
}

Function Call Output

{
  "type": "function_call",
  "id": "fc_123",
  "call_id": "call_abc",
  "name": "get_weather",
  "arguments": "{\"location\": \"Paris\"}",
  "status": "completed"
}

Hosted Tool Search Call

{
  "type": "tool_search_call",
  "id": "ts_123",
  "status": "completed"
}

This item records discovery activity. It does not execute or approve a client function. A revealed function selected by the model appears separately as function_call.

Reasoning Output (reasoning-capable models)

{
  "type": "reasoning",
  "id": "reasoning_123",
  "status": "completed",
  "summary": [
    {
      "type": "summary_text",
      "text": "I analyzed the problem by..."
    }
  ],
  "content": [
    {
      "type": "reasoning_text",
      "text": "Detailed reasoning goes here."
    }
  ],
  "encrypted_content": null
}

Web Search Call Output

{
  "type": "web_search_call",
  "id": "ws_123",
  "status": "completed",
  "action": { "query": "search query" },
  "results": [{ "url": "...", "title": "...", "snippet": "..." }]
}

Image Generation Call Output

{
  "type": "image_generation_call",
  "id": "ig_123",
  "status": "completed",
  "result": {
    "b64_json": "...",
    "url": "...",
    "revised_prompt": "..."
  }
}

Computer Call Output

{
  "type": "computer_call",
  "id": "cc_123",
  "call_id": "call_abc123",
  "status": "completed",
  "action": { "type": "click" },
  "pending_safety_checks": [{ "id": "...", "code": "...", "message": "..." }]
}

Output Item Status Values

Status	Description
`completed`	Item finished successfully
`in_progress`	Item still being generated
`incomplete`	Item was truncated/interrupted

Output Text Parts

Output text parts include annotations and logprobs:

{
  "type": "output_text",
  "text": "Hello world",
  "annotations": [],
  "logprobs": [
    {
      "token": "Hello",
      "logprob": -0.5,
      "bytes": [72, 101, 108, 108, 111],
      "top_logprobs": [
        { "token": "Hello", "logprob": -0.5, "bytes": [72, 101, 108, 108, 111] },
        { "token": "Hi", "logprob": -1.2, "bytes": [72, 105] }
      ]
    }
  ]
}

Annotation Types

URL Citation

{
  "type": "url_citation",
  "start_index": 0,
  "end_index": 10,
  "url": "https://...",
  "title": "Page Title"
}

File Citation

{
  "type": "file_citation",
  "start_index": 0,
  "end_index": 10,
  "file_id": "file_..."
}

File Path

{
  "type": "file_path",
  "start_index": 0,
  "end_index": 10,
  "file_id": "file_..."
}

Streaming

See also: Streaming Protocol (SSE). Enable streaming to receive incremental response updates:

{
  "model": "openai/gpt-5.6-sol",
  "input": "Write a short story",
  "stream": true
}

Streaming Response

The response is delivered as Server-Sent Events (SSE):

data: {"type":"response.created","response":{...},"sequence_number":0}

data: {"type":"response.in_progress","response":{...},"sequence_number":1}

data: {"type":"response.output_item.added","output_index":0,"item":{...},"sequence_number":2}

data: {"type":"response.output_text.delta","item_id":"msg_...","output_index":0,"content_index":0,"delta":"The ","logprobs":[...],"sequence_number":3}

data: {"type":"response.output_text.delta","item_id":"msg_...","output_index":0,"content_index":0,"delta":"capital ","logprobs":[...],"sequence_number":4}

data: {"type":"response.output_text.done","item_id":"msg_...","output_index":0,"content_index":0,"text":"The capital of France is Paris.","logprobs":[...],"sequence_number":10}

data: {"type":"response.completed","response":{...},"sequence_number":11}

data: [DONE]

Streaming Event Types

Event	Description
`response.created`	Response object created
`response.in_progress`	Processing started
`response.output_item.added`	New output item started
`response.output_item.done`	Output item completed
`response.content_part.added`	Content part started
`response.content_part.done`	Content part completed
`response.output_text.delta`	Incremental text chunk
`response.output_text.done`	Text content completed
`response.reasoning.delta`	Incremental reasoning text
`response.reasoning.done`	Reasoning content completed
`response.function_call_arguments.delta`	Incremental function arguments
`response.function_call_arguments.done`	Function call completed
`response.completed`	Response completed successfully
`response.incomplete`	Response truncated
`response.failed`	Response failed

Updated Event Fields

All content/output events include item_id for the parent output item.
Text delta/done events include logprobs.

Example response.output_text.delta:

{
  "type": "response.output_text.delta",
  "item_id": "msg_...",
  "output_index": 0,
  "content_index": 0,
  "delta": "Hello",
  "logprobs": [...],
  "sequence_number": 5
}

Conversation Threading

Chain responses together for multi-turn conversations. You can use previous_response_id or the conversation object (id or messages) to manage context.

First Request

{
  "model": "openai/gpt-5.6-sol",
  "input": "My name is Alice."
}

Response includes id: "resp_abc123"

Follow-up Request

{
  "model": "openai/gpt-5.6-sol",
  "input": "What is my name?",
  "previous_response_id": "resp_abc123"
}

The model has access to the conversation history and responds: “Your name is Alice.” Note: previous_response_id requires authentication, store: true on previous responses, and effective retention greater than 0.

Background Mode

For long-running requests, use background mode to receive an immediate response and poll for results.

Initiate Background Request

{
  "model": "openai/gpt-5.6-sol",
  "input": "Write a detailed analysis...",
  "background": true
}

Immediate Response (202 Accepted)

{
  "id": "resp_abc123",
  "object": "response",
  "created_at": 1699000000,
  "model": "openai/gpt-5.6-sol",
  "status": "queued",
  "output": []
}

Poll for Completion

GET /v1/responses/resp_abc123
Authorization: Bearer YOUR_API_KEY

Keep polling until status is completed, failed, or incomplete. Constraints:

Cannot be combined with stream: true
Requires authentication
Effective retention must be greater than 0
Maximum processing time: approximately 800 seconds

Retrieve Response

GET /v1/responses/{id}
Authorization: Bearer YOUR_API_KEY

Response

Returns the full response object (same format as POST response).

Errors

404 - Response not found or belongs to different account
401 - Authentication required/invalid

Delete Response

DELETE /v1/responses/{id}
Authorization: Bearer YOUR_API_KEY

Response

{
  "id": "resp_abc123",
  "object": "response.deleted",
  "deleted": true
}

Error Handling

Error Response Format

{
  "error": {
    "code": "missing_required_parameter",
    "message": "model is required"
  }
}

HTTP Status Codes

HTTP Status	Description
`400`	Invalid request parameters
`401`	Missing or invalid API key
`403`	Insufficient permissions
`404`	Resource not found
`429`	Rate limit exceeded
`500`	Internal server error
`503`	Service unavailable

Common Error Codes

Code	Description
`missing_required_parameter`	Required parameter not provided
`model_not_found`	Specified model does not exist
`response_not_found`	Response ID not found
`invalid_response_id`	Invalid response ID format
`invalid_request_error`	Invalid request shape/value (for example retention out of range or mismatched alias fields)
`authentication_required`	No API key provided
`invalid_api_key`	API key is invalid or inactive

Complete Examples

Simple Text Completion

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "Explain quantum computing in one sentence."
  }'

Multi-turn Conversation

# First turn
curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "I want to learn Python programming."
  }'

# Second turn (using response ID from first request)
curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "Where should I start?",
    "previous_response_id": "resp_abc123"
  }'

Streaming Response

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "Write a haiku about programming",
    "stream": true
  }'

Per-request Retention Override

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gpt-4o",
    "input": "hello",
    "store": true,
    "retention_days": 3
  }'

Function Calling

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "What is the weather in Tokyo?",
    "tools": [
      {
        "type": "function",
        "name": "get_weather",
        "description": "Get current weather for a location",
        "parameters": {
          "type": "object",
          "properties": {
            "location": { "type": "string" }
          },
          "required": ["location"]
        }
      }
    ]
  }'

Submitting Tool Results

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": [
      {
        "type": "message",
        "role": "user",
        "content": "What is the weather in Tokyo?"
      },
      {
        "type": "function_call",
        "id": "fc_1",
        "call_id": "call_123",
        "name": "get_weather",
        "arguments": "{\"location\": \"Tokyo\"}"
      },
      {
        "type": "function_call_output",
        "call_id": "call_123",
        "output": "{\"temperature\": 18, \"condition\": \"cloudy\"}"
      }
    ]
  }'

Image Input (Vision)

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": [
      {
        "type": "message",
        "role": "user",
        "content": [
          { "type": "input_text", "text": "What is in this image?" },
          { "type": "input_image", "image_url": "https://example.com/photo.jpg", "detail": "auto" }
        ]
      }
    ]
  }'

Video Input (Understanding)

Video input is separate from video generation and is available only on models advertising video capability. See the Video Input guide for source rules, limits, YouTube behavior, and validation errors.

JSON Output

curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "List the planets in our solar system",
    "text": {
      "format": { "type": "json_object" }
    }
  }'

Background Processing

# Start background request
curl -X POST https://api.nano-gpt.com/api/v1/responses \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "openai/gpt-5.6-sol",
    "input": "Generate a comprehensive report...",
    "background": true
  }'

# Poll for results
curl https://api.nano-gpt.com/api/v1/responses/resp_abc123 \
  -H "Authorization: Bearer YOUR_API_KEY"

Limitations

Deep research models: Deep research variants are not supported.
GPU-TEE streaming: Streaming is not supported for GPU-TEE models. Use /v1/chat/completions for these models.
Background mode: Maximum duration is approximately 800 seconds.
Metadata limits: Maximum 16 keys, 64 character key names, 512 character values.
Hosted tool search: Available only on compatible models in foreground Responses requests. It cannot currently be combined with background mode or other hosted built-ins. See Hosted tool search.

Service tiers (flex and priority)

Set service_tier to request a non-default capacity tier on providers that support service tiers:

auto or omitted: use NanoGPT’s normal routing and the provider default.
default: request the provider’s standard tier where the provider accepts an explicit default value.
flex: request lower-cost, variable-capacity processing where supported.
priority: request higher-cost priority processing where supported.

Behavior notes:

Service tier availability is model- and provider-specific. Model pages show which tiers are supported.
Flex and priority tiers are only applied when the routed provider supports them.
Header provider overrides (like X-Provider) and explicit provider selection are honored for pricing and x402 estimates.
Provider-native web search can force routing; tier pricing follows that routing.
If you explicitly force a provider that does not support service tiers, the requested tier may be ignored by the upstream provider, or routing and pricing may differ from the default route.

Billing note:

Flex tier billing uses flex pricing where applicable.
Priority tier billing uses priority pricing where applicable.
High-context pricing may also apply for models and providers with separate high-context SKUs, such as es2k pricing for GPT-5.5/GPT-5.4 where available.

Example: flex tier

{
  "model": "openai/gpt-5.5",
  "input": "Say hi in one sentence.",
  "service_tier": "flex"
}

Example: priority tier

{
  "model": "openai/gpt-5.5",
  "input": "Say hi in one sentence.",
  "service_tier": "priority"
}

Response Headers

All responses include:

Header	Description
`X-Request-ID`	Unique request/response identifier
`Content-Type`	`application/json` or `text/event-stream`

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

X-Provider

string

Optional explicit provider override for supported open-source models (case-insensitive). Explicit provider selection is billed pay-as-you-go at the selected provider's price, including provider-selection markup; for subscription users it bypasses subscription coverage for that request.

X-Billing-Mode

string

Optional billing override to force pay-as-you-go without an explicit provider, or to apply saved provider preferences to subscription-included traffic (e.g., paygo). Header name is case-insensitive.

X-Team-Id

string

Optional team context override for API-key requests. If provided, it must reference a team the caller belongs to.

x-x402

enum<string>

Set to true on unauthenticated accountless x402 quote requests. Without this header, unauthenticated requests return 401 missing_api_key.

Available options:

true

Body

application/json

Parameters for the response request

model

string

required

Model ID to use for the response. Provider-selection-capable models may include routing preference suffixes such as ':fast', ':speed', ':cheap', ':price', ':latency', ':throughput', ':floor', ':tools', ':caching', ':cache', or ':cached'.

input

required

Prompt string or array of input items. Use an input_video content part with a video_url field for video understanding.

billing_mode

string

Billing override to force pay-as-you-go without an explicit provider, or to apply saved provider preferences to subscription-included traffic. Accepted values (case-insensitive): paygo, pay-as-you-go, pay_as_you_go, paid, payg.

billingMode

string

Alias for billing_mode.

instructions

string

System instructions for the model

max_output_tokens

integer

Maximum tokens in the response

Required range: x >= 16

temperature

number

Sampling temperature (not supported by reasoning models)

Required range: 0 <= x <= 2

top_p

number

Nucleus sampling parameter

Required range: 0 <= x <= 1

tools

object[]

Tools available to the model. The Responses-only hosted tool-search pilot accepts one nanogpt:tool_search or tool_search entry plus function tools marked defer_loading: true on compatible models.

Option 1
Option 2
Option 3

Show child attributes

tool_choice

How the model should use tools

parallel_tool_calls

boolean

Allow multiple tool calls in parallel

stream

boolean

default:false

Enable streaming responses

store

boolean

default:false

Store the response locally for later retrieval/threading/background processing. Set false to disable stored Responses API data for the request.

retention_days

integer | null

Per-request retention override in days (0..365). Use 0 to disable retention for the request; use null to fall back to configured defaults.

Required range: 0 <= x <= 365

retentionDays

integer | null

Alias for retention_days (0..365). If both are provided, values must match.

Required range: 0 <= x <= 365

previous_response_id

string

Link to previous response for conversation threading

reasoning

object

Reasoning configuration. Setting reasoning.effort to any non-none value explicitly requests reasoning mode.

text

object

Text/format configuration

metadata

object

Custom metadata

truncation

enum<string>

Truncation strategy

Available options:

auto,

disabled

user

string

Unique user identifier

seed

integer

Optional integer forwarded on model/provider routes that support seeded sampling. This may improve reproducibility but does not guarantee identical output. Results can change if NanoGPT selects a different automatic or fallback route, or if the provider changes its backend.

background

boolean

Enable background/async processing

service_tier

enum<string>

Optional service tier: "auto", "default", "flex", or "priority". Use "flex" for lower-cost variable-capacity processing or "priority" for higher-cost priority processing where supported by the routed model/provider.

Available options:

auto,

default,

flex,

priority

advisor

object

Allows the executor model to consult one different advisor model. Auto mode lets the executor decide whether to consult; required mode forces one consultation request. Advisor is non-streaming and available only for platform-billed pay-as-you-go API-key requests. Subscriptions, BYOK, accountless x402, Private Mode, inline moderation, client tools, structured outputs, memory, and server-side content enhancements are rejected before orchestration. Each completed executor, advisor, and continuation phase is billed separately.

Show child attributes

Response

Response created

Response object returned by the Responses API

string

object

string

created_at

integer

model

string

status

enum<string>

Available options:

queued,

in_progress,

completed,

incomplete,

failed,

cancelled

output

object[]

output_text

string

usage

object

error

object

incomplete_details

object

metadata

object

service_tier

string

advisor

object

Advisor orchestration status and per-phase usage. Present on responses to requests that use the Advisor extension.

Show child attributes

​Overview

​Authentication

​Endpoints

​Batch processing

​BYOK Encryption (Stored Responses)

​Create Response

​Request

​Request Body

​Reproducibility guidance

​Response Storage And Retention

​Retention Resolution

​Input Types

​Simple String Input

​Array Input

​Input Item Types

​Message Item

​Content Part Types

​Image Input

​Video Input

​Function Call Item

​Function Call Output Item

​Tools

​Function Tool

​Hosted Tool Search

​Web Search Tool

​File Search Tool

​Code Interpreter Tool

​MCP Tool

​Image Generation Tool

​Tool Choice

​Function Tool Normalization

​Reasoning Configuration

​Text/Format Configuration

​Text Parameter Structure

​Format Types

​Verbosity Values

​JSON Schema Format

​Response Format

​Successful Response

​Response Fields

​Usage Object

​Response Status Values

​reasoning Response Field

​text Response Field (Resolved)

​Output Item Types

​Message Output

​Function Call Output

​Hosted Tool Search Call

​Reasoning Output (reasoning-capable models)

​Web Search Call Output

​Image Generation Call Output

​Computer Call Output

​Output Item Status Values

​Output Text Parts

​Annotation Types

​URL Citation

​File Citation

​File Path

​Streaming

​Streaming Response

​Streaming Event Types

​Updated Event Fields

​Conversation Threading

​First Request

​Follow-up Request

​Background Mode

​Initiate Background Request

​Immediate Response (202 Accepted)

​Poll for Completion

​Retrieve Response

​Response

​Errors

​Delete Response

​Response

​Error Handling

​Error Response Format

​HTTP Status Codes

​Common Error Codes

​Complete Examples

​Simple Text Completion

Overview

Authentication

Endpoints

Batch processing

BYOK Encryption (Stored Responses)

Create Response

Request

Request Body

Reproducibility guidance

Response Storage And Retention

Retention Resolution

Input Types

Simple String Input

Array Input

Input Item Types

Message Item

Content Part Types

Image Input

Video Input

Function Call Item

Function Call Output Item

Tools

Function Tool

Hosted Tool Search

Web Search Tool

File Search Tool

Code Interpreter Tool

MCP Tool

Image Generation Tool

Tool Choice

Function Tool Normalization

Reasoning Configuration

Text/Format Configuration

Text Parameter Structure

Format Types

Verbosity Values

JSON Schema Format

Response Format

Successful Response

Response Fields

Usage Object

Response Status Values

`reasoning` Response Field

`text` Response Field (Resolved)

Output Item Types

Message Output

Function Call Output

Hosted Tool Search Call

Reasoning Output (reasoning-capable models)

Web Search Call Output

Image Generation Call Output

Computer Call Output

Output Item Status Values

Output Text Parts

Annotation Types

URL Citation

File Citation

File Path

Streaming

Streaming Response

Streaming Event Types

Updated Event Fields

Conversation Threading

First Request

Follow-up Request

Background Mode

Initiate Background Request

Immediate Response (202 Accepted)

Poll for Completion

Retrieve Response

Response

Errors

Delete Response

Response

Error Handling

Error Response Format

HTTP Status Codes

Common Error Codes

Complete Examples

Simple Text Completion