> ## Documentation Index > Fetch the complete documentation index at: https://docs.infyrence.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a chat completion > Generate a model response for a conversation. ## OpenAPI ````yaml POST /v1/chat/completions openapi: 3.1.0 info: title: Infyrence API version: 1.0.0 summary: Unified, OpenAI-compatible AI gateway for 200+ models. description: > Infyrence is a unified, OpenAI-compatible inference gateway. Call 200+ models from every major provider through a single endpoint and one API key, with automatic failover and edge-fast routing. ## Authentication Authenticate every request with your Infyrence API key as a Bearer token: ``` Authorization: Bearer sk-... ``` Create and manage keys in your [dashboard](https://www.infyrence.com/dashboard/api-keys). ## OpenAI compatibility The API mirrors the OpenAI Chat Completions API. To migrate an existing integration, point the base URL at `https://api.infyrence.com/v1` and set the `model` to any model from `GET /v1/models`, no other changes required. ## Pricing Billing is usage-based, per model: you pay for input and output tokens at each model's published per-million-token rate. See [infyrence.com/pricing](https://www.infyrence.com/pricing). contact: name: Infyrence Support url: https://www.infyrence.com/contact email: support@infyrence.com license: name: Proprietary url: https://www.infyrence.com/terms termsOfService: https://www.infyrence.com/terms servers: - url: https://api.infyrence.com description: Production security: - bearerAuth: [] tags: - name: Chat description: Create model responses from a list of messages. - name: Models description: List the models available through the gateway. - name: Health description: Public liveness and status endpoints. paths: /v1/chat/completions: post: tags: - Chat summary: Create a chat completion description: | Generate a model response for the given conversation. Set `stream: true` to receive the response incrementally as Server-Sent Events (SSE). operationId: createChatCompletion requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ChatCompletionRequest' examples: basic: summary: A simple completion value: model: claude-sonnet-5 messages: - role: system content: You are a helpful assistant. - role: user content: Explain quantum entanglement in one sentence. streaming: summary: A streaming completion value: model: gpt-5.5 messages: - role: user content: Write a haiku about the edge. stream: true responses: '200': description: > The chat completion. When `stream` is `false` (default), the body is a single `ChatCompletionResponse` JSON object. When `stream` is `true`, the body is a `text/event-stream` of `ChatCompletionChunk` objects , each sent as a `data: {...}` line, terminated by a final `data: [DONE]`. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/ChatCompletionResponse' text/event-stream: schema: $ref: '#/components/schemas/ChatCompletionChunk' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/PaymentRequired' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' '503': $ref: '#/components/responses/UpstreamUnavailable' security: - bearerAuth: [] components: schemas: ChatCompletionRequest: type: object required: - model - messages properties: model: type: string description: The model to use. Any id returned by `GET /v1/models`. examples: - claude-sonnet-5 - gpt-5.5 - gemini-3.1-pro messages: type: array minItems: 1 description: The conversation so far, as a list of messages. items: $ref: '#/components/schemas/ChatMessage' temperature: type: number minimum: 0 maximum: 2 description: Sampling temperature. Higher is more random. top_p: type: number minimum: 0 maximum: 1 description: Nucleus sampling probability mass. max_tokens: type: integer minimum: 1 description: Maximum number of tokens to generate in the completion. stream: type: boolean default: false description: If true, stream the response as Server-Sent Events. stop: description: Up to a few sequences where generation stops. oneOf: - type: string - type: array items: type: string frequency_penalty: type: number minimum: -2 maximum: 2 description: Penalize new tokens by their existing frequency in the text so far. presence_penalty: type: number minimum: -2 maximum: 2 description: >- Penalize new tokens by whether they already appear in the text so far. 'n': type: integer minimum: 1 description: Number of completions to generate. seed: type: integer description: Best-effort deterministic sampling seed. additionalProperties: false ChatCompletionResponse: type: object required: - id - object - created - model - choices - usage properties: id: type: string object: type: string const: chat.completion created: type: integer description: Unix timestamp (seconds) of when the completion was created. model: type: string choices: type: array items: $ref: '#/components/schemas/ChatCompletionChoice' usage: $ref: '#/components/schemas/Usage' ChatCompletionChunk: type: object description: One streamed chunk of a chat completion, sent as an SSE `data:` line. required: - id - object - created - model - choices properties: id: type: string object: type: string const: chat.completion.chunk created: type: integer model: type: string choices: type: array items: $ref: '#/components/schemas/ChatCompletionChunkChoice' usage: $ref: '#/components/schemas/Usage' ChatMessage: type: object required: - role properties: role: type: string enum: - system - user - assistant - tool description: The role of the message author. content: type: - string - 'null' description: >- The text content of the message. May be null for an assistant message that only issues tool calls. name: type: string description: An optional name for the participant. tool_calls: type: array description: Tool calls issued by the assistant, if any. items: $ref: '#/components/schemas/ToolCall' tool_call_id: type: string description: >- For a `tool` message, the id of the tool call this message responds to. additionalProperties: false ChatCompletionChoice: type: object required: - index - message - finish_reason properties: index: type: integer message: $ref: '#/components/schemas/ChatMessage' finish_reason: type: - string - 'null' enum: - stop - length - tool_calls - null Usage: type: object required: - prompt_tokens - completion_tokens - total_tokens properties: prompt_tokens: type: integer completion_tokens: type: integer total_tokens: type: integer ChatCompletionChunkChoice: type: object required: - index - delta - finish_reason properties: index: type: integer delta: $ref: '#/components/schemas/ChatMessage' finish_reason: type: - string - 'null' enum: - stop - length - tool_calls - null Error: type: object required: - error properties: error: type: object required: - message - type properties: message: type: string description: A human-readable description of the error. type: type: string description: >- The category of error, e.g. `invalid_request_error`, `authentication_error`, `rate_limit_error`, `upstream_error`. code: type: - string - 'null' description: A stable, machine-readable error code, when available. request_id: type: string description: The id of the failed request, for tracing with support. additionalProperties: false ToolCall: type: object required: - id - type - function properties: id: type: string type: type: string enum: - function function: type: object required: - name - arguments properties: name: type: string arguments: type: string description: The function arguments as a JSON-encoded string. additionalProperties: false headers: X-Request-Id: description: >- A unique id for the request, echoed on every response and included in error bodies for tracing. schema: type: string responses: BadRequest: description: The request was malformed or failed validation. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: 'messages: Required' type: invalid_request_error code: null request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 Unauthorized: description: The API key is missing or invalid. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: Invalid API key. type: authentication_error code: invalid_api_key request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 PaymentRequired: description: >- The account has no remaining balance for platform models. Add funds, or use your own provider key (BYOK). headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: >- Insufficient balance. Add funds, or use your own provider key (BYOK) to continue. type: insufficient_credits code: null request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 NotFound: description: The requested model or resource was not found. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: The requested model was not found. type: not_found code: model_not_found request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 RateLimited: description: Too many requests. Retry after the interval in the `Retry-After` header. headers: Retry-After: description: Seconds to wait before retrying. schema: type: integer X-RateLimit-Limit: schema: type: integer X-RateLimit-Remaining: schema: type: integer X-RateLimit-Reset: schema: type: integer X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: Rate limit exceeded. Please slow down. type: rate_limit_error code: rate_limited request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 UpstreamUnavailable: description: The model is temporarily unavailable. Retry after a short delay. headers: X-Request-Id: $ref: '#/components/headers/X-Request-Id' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: >- The model is temporarily unavailable. Please try again in a few moments. type: upstream_error code: upstream_unavailable request_id: 4f0c2e1a-9b3d-4a2e-8c1f-77a0b2d5e6f1 securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: sk-... description: 'Your Infyrence API key, sent as `Authorization: Bearer sk-...`.' ````