PII Redaction

NanoGPT supports optional PII redaction for API and web chat requests. When redaction is enabled, NanoGPT routes the request through Grepture before it reaches the selected model. Grepture masks supported personal information before the model sees the prompt, then restores masked values in the model response when possible. This is useful when you want to reduce the amount of personal or sensitive data sent to model providers while still getting a useful final answer. PII redaction is opt-in and costs $0.0005 per redacted request.

How Redaction Works

When redaction is enabled:

The user sends a request to NanoGPT.
NanoGPT routes that request through Grepture.
Grepture detects supported personal information and replaces it with temporary placeholders before the request reaches the model.
The model processes the redacted prompt.
Grepture restores masked personal information in the response where possible.
NanoGPT returns the final response to the user.

Simple flow:

User -> NanoGPT -> Grepture -> Model -> Grepture -> NanoGPT -> User

Credential-like secrets are handled differently from normal PII. If the redaction layer detects API keys, tokens, private keys, webhooks, passwords, or similar secrets, those values are replaced with safe labels and are not restored into the response. This is intentional: a leaked credential should not be reinserted into model output.

Supported API Endpoints

PII redaction can be enabled on:

POST /v1/chat/completions
POST /v1/completions
POST /v1/responses

Enable With API Headers

Pass any one of these headers with a truthy value:

Header	Recommended
`redaction: true`	Yes
`redacted: true`	No
`piiredaction: true`	No
`piiredacted: true`	No

Truthy values accepted by the API:

true
1
yes
on

Recommended header:

redaction: true

Chat Completions Example

curl https://nano-gpt.com/api/v1/chat/completions \
  -H "Authorization: Bearer $NANOGPT_API_KEY" \
  -H "Content-Type: application/json" \
  -H "redaction: true" \
  -d '{
    "model": "openai/gpt-5.5",
    "messages": [
      {
        "role": "user",
        "content": "Email jane@example.com and tell her the appointment is tomorrow."
      }
    ]
  }'

Responses Example

curl https://nano-gpt.com/api/v1/responses \
  -H "Authorization: Bearer $NANOGPT_API_KEY" \
  -H "Content-Type: application/json" \
  -H "redaction: true" \
  -d '{
    "model": "openai/gpt-5.5",
    "input": "Summarize this customer note: John Smith called from 555-123-4567."
  }'

Disable For One Request

If redaction is enabled by an account-level or API-key default, a request can opt out with any supported redaction header set to a falsy value:

Header	Recommended
`redaction: false`	Yes
`redacted: false`	No
`piiredaction: false`	No
`piiredacted: false`	No

Falsy values accepted by the API:

false
0
no
off

Recommended opt-out header:

redaction: false

If the same request explicitly enables redaction with a model suffix such as :redaction, redaction remains enabled.

Enable With Model Suffixes

You can also enable redaction by appending a redaction suffix to the model name:

Suffix
`:redaction`
`:redacted`
`:piiredaction`
`:piiredacted`

Example:

{
  "model": "openai/gpt-5.5:redaction",
  "messages": [
    {
      "role": "user",
      "content": "My phone number is 555-123-4567. Write a short reminder text."
    }
  ]
}

NanoGPT strips the redaction suffix before sending the request onward, so the model is still resolved as the base model. The suffix is only used to turn redaction on for that request. Redaction suffixes can be combined with other supported NanoGPT model routing suffixes. For example:

{
  "model": "openai/gpt-5.5:redaction:online",
  "messages": [
    {
      "role": "user",
      "content": "Search for updates related to this customer domain: example.com"
    }
  ]
}

For general suffix composition rules, see Model Suffixes.

Enable In Web Chat

In the NanoGPT web app, users can enable PII redaction from:

Settings > Privacy > PII redaction for chats

When this setting is enabled, web chat requests are routed through the redaction layer automatically. The same $0.0005 per-request redaction charge applies.

API Default Settings

Users can enable redaction by default for API requests from:

Settings > Privacy > PII redaction for API requests

When this account-level API setting is enabled, supported API text requests are routed through the redaction layer by default. Users can still opt out per request with redaction: false. API keys can also be configured individually from the API key settings modal:

API key setting	Behavior
Inherit account	Use the account-level API default.
Always redact	Redact requests made with this API key unless the request opts out.
Never redact	Do not apply the account-level API redaction default to this API key.

Explicit per-request headers and model suffixes are still the clearest way to control redaction for a single request.

What Gets Redacted

The redaction layer is designed to detect and mask common personal information and sensitive credentials.

Personal Information

Supported PII categories:

Category	Description
Email	Email addresses
Phone	Phone numbers
SSN	US Social Security numbers
Credit card	Payment card numbers
IP address	IPv4 and IPv6-style network addresses
Address	Physical addresses
Name	Person names
Date of birth	Birth dates and DOB-style values

For these PII categories, values are temporarily replaced with placeholders before reaching the model. When the response comes back, Grepture restores placeholders to the original values where possible.

Secrets And Credentials

NanoGPT also replaces common credential-like values with safe labels. These values are not restored. Examples of secret categories:

Category	Behavior
API keys and access tokens	Replaced with a safe label
Cloud credentials and session tokens	Replaced with a safe label
Webhook URLs	Replaced with a safe label
Private key material	Replaced with a safe label
Password or secret assignments	Replaced with a safe label
Service account identifiers	Replaced with a safe label
FTP-style embedded credentials	Replaced with a safe label

PII such as names, emails, and phone numbers is masked and restored. Credentials such as API keys, private keys, webhooks, and passwords are replaced permanently and are not restored into the model response.

Pricing

PII redaction costs $0.0005 per redacted request. This charge is added only when redaction is enabled for the request. It is shown as a separate PII redaction add-on in usage details. The redaction charge is per request, not per token.

Failure Behavior

Redaction is fail-closed. If a request asks for redaction and the redaction layer cannot be used, NanoGPT does not silently retry the request without redaction. If redaction is enabled but the redaction service is unavailable, the request may fail rather than being sent without redaction. This prevents accidental unredacted fallback behavior.

Limitations

Redaction is a privacy and safety layer, not a compliance guarantee.
Detection is best-effort and may not catch every possible form of personal information or secret.
PII restoration depends on the placeholder appearing in the model response. If the model rewrites, omits, or transforms the placeholder, restoration may not occur exactly as expected.
Redaction applies to request content that can be processed as text. It should not be treated as pixel-level image redaction, file sanitization, malware scanning, or document de-identification.
Users should still avoid sending unnecessary personal data or credentials to AI systems.

FAQ

Does redaction change the model I selected?

No. Redaction changes the route the request takes before it reaches the model. It does not change the selected model.

Does redaction work with streaming?

Yes. Redaction is intended to work with streaming responses. The request is still routed through the redaction layer before the model sees it.

Are redacted values restored in the final answer?

For supported personal information categories, yes, where possible. For secrets and credentials, no. Secrets are replaced with safe labels and are not restored.

Can I enable redaction globally for API requests?

Yes. Users can enable an account-level API redaction default in Settings > Privacy. API keys can inherit that default, always redact, or opt out of the account default. Per-request headers and model suffixes are also supported.

Can I opt out if my account or API key has redaction enabled by default?

Yes. Send redaction: false on the request to opt out of account-level or API-key redaction defaults. Model suffixes such as :redaction explicitly enable redaction for that request.

What happens if I use both the header and the model suffix?

Redaction is enabled. There is still only one redaction charge for the request.

​PII Redaction

​How Redaction Works

​Supported API Endpoints

​Enable With API Headers

​Chat Completions Example

​Responses Example

​Disable For One Request

​Enable With Model Suffixes

​Enable In Web Chat

​API Default Settings

​What Gets Redacted

​Personal Information

​Secrets And Credentials

​Pricing

​Failure Behavior

​Limitations

​FAQ

​Does redaction change the model I selected?

​Does redaction work with streaming?

​Are redacted values restored in the final answer?

​Can I enable redaction globally for API requests?

​Can I opt out if my account or API key has redaction enabled by default?

​What happens if I use both the header and the model suffix?