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Pay-As-You-Go Billing Override (API)

This override forces a request to be treated as paid (pay-as-you-go), even when the user has an active subscription and the model is subscription-included. It is intended for API documentation and support.

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What It Does

  • Forces a request to be treated as paid (pay-as-you-go).
  • Bypasses subscription coverage for that request.
  • Allows provider selection on subscription-included models when the model supports provider selection.
  • Applies provider selection markup when a provider is explicitly chosen.
  • Does not change which models support provider selection.

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When to Use It

Use billing_mode: "paygo" when:
  • A subscriber wants to select a specific upstream provider for a model.
  • A subscriber wants to pay per-request even if the model is normally covered by subscription.

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Supported Inputs

Header
  • X-Billing-Mode: paygo (header name is case-insensitive)
  • x-billing-mode is also accepted
Body (all endpoints)
  • "billing_mode": "paygo"
  • Alias: "billingMode": "paygo"
Accepted values (case-insensitive)
  • paygo
  • pay-as-you-go
  • pay_as_you_go
  • paid
  • payg
Precedence: Body value wins if both body and header are present.

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API Examples

Chat Completions: 
POST /api/v1/chat/completions
X-Billing-Mode: paygo
X-Provider: chutes

{
  "model": "zai-org/GLM-4.6",
  "messages": [
    { "role": "user", "content": "Hello" }
  ]
}
Completions: 
POST /api/v1/completions
X-Billing-Mode: paygo
X-Provider: deepinfra

{
  "model": "zai-org/GLM-4.6",
  "prompt": "Hello"
}
Responses: 
POST /api/v1/responses
X-Billing-Mode: paygo

{
  "model": "gpt-4o-mini",
  "input": "Hello"
}

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Provider Selection Notes

  • Provider selection only works for models that support it.
  • If a model does not support provider selection, X-Provider is ignored.
  • For provider-selectable models, the request is treated as paid and provider selection markup applies when a provider is explicitly chosen.

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Subscription and Limits Behavior

When billing_mode: "paygo" is set:
  • The request is not eligible for subscription coverage.
  • Subscription quota is not consumed.
  • Pay-as-you-go balance checks apply as normal.
If subscription.enablePaidModelsApi is false, the request is rejected (same as any other paid API request).

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FAQ

Does this affect which models are available? No. It only changes billing eligibility. Model availability is unchanged. Does it force a provider for non-selectable models? No. It only affects billing, not routing, unless the model supports provider selection. Can I combine this with BYOK? Yes. BYOK still works; paygo override only changes subscription eligibility.