> ## Documentation Index > Fetch the complete documentation index at: https://docs.anyfast.ai/llms.txt > Use this file to discover all available pages before exploring further. # Chat Completions > Creates a model response for the given chat conversation. ## OpenAPI ````yaml api-reference/endpoints/openapi/openai/openapi.yaml POST /v1/chat/completions openapi: 3.1.0 info: title: OpenAI Compatible Endpoint description: >- OpenAI-compatible chat completions endpoint supporting all chat models via Anyfast version: 1.0.0 servers: - url: https://www.anyfast.ai security: - bearerAuth: [] paths: /v1/chat/completions: post: summary: Chat Completion description: Creates a model response for the given chat conversation. operationId: createChatCompletionCompatible requestBody: required: true content: application/json: schema: type: object required: - model - messages properties: model: type: string enum: - claude-sonnet-5 - claude-sonnet-4-6 - claude-sonnet-4-5-20250929 - claude-sonnet-4-20250514 - claude-opus-4-6 - claude-opus-4-5-20251101 - claude-opus-4-1-20250805 - claude-opus-4-20250514 - claude-haiku-4-5-20251001 - claude-3-7-sonnet-20250219 - claude-3-5-sonnet-20241022 - gpt-5-4 - gpt-5.4-mini - gpt-5-3-codex - gpt-5-2 - gpt-5-2-chat - gpt-5-2-chat-latest - gpt-5-2-codex - gpt-5-1 - gpt-5-1-chat - gpt-5-1-chat-latest - gpt-5-1-codex-mini - gpt-5 - gpt-5-chat-latest - gpt-5-pro - gpt-5-codex - gpt-5-codex-high - gpt-5-codex-low - gpt-5-mini - gpt-5-nano - gpt-4o - gpt-4o-mini - gpt-4-1 - gpt-4 - deepseek-v3-2-speciale - deepseek-v3-2 - deepseek-v3-2-exp - deepseek-v3-2-251201 - deepseek-v3-1-terminus - deepseek-v3-1 - deepseek-v3 - qwen3.5-397b-a17b - qwen3-coder-next - qwen3-coder - qwen3-235b-a22b - qwen3-32b - qwen3-14b - qwen2.5-72b-instruct - doubao-seed-2.0-pro - doubao-seed-2.0-code - doubao-seed-2.0-lite - doubao-seed-2.0-mini - doubao-seed-1-8-251228 - doubao-seed-1-6-flash-250828 - doubao-seed-1-6-251015 - doubao-seed-1-6-lite-251015 - doubao-seed-1-6-vision-250815 - minimax-m2.5 - minimax-m2.1 - kimi-k2.5 - grok-3 - grok-3-mini - grok-4-fast-reasoning - grok-4-fast-non-reasoning - grok-4-1-fast-reasoning - grok-4-1-fast-non-reasoning - gemini-3.1-pro-preview - gemini-3.1-flash-image - gemini-3-pro-preview - gemini-3-flash-preview - gemini-2.5-pro - gemini-2.5-flash - gemini-2.0-flash - glm-4.7 description: Model ID to use for completion. example: claude-sonnet-5 messages: type: array minItems: 1 description: A list of messages comprising the conversation so far. items: type: object required: - role - content properties: role: type: string enum: - system - user - assistant content: oneOf: - type: string - type: array items: type: object example: - role: user content: Hello! max_tokens: type: integer minimum: 1 description: >- The maximum number of tokens to generate in the chat completion. temperature: type: number minimum: 0 maximum: 2 default: 1 description: >- Sampling temperature between 0 and 2. Higher values make output more random, lower values more deterministic. example: 1 top_p: type: number minimum: 0 maximum: 1 description: Nucleus sampling threshold. An alternative to temperature. frequency_penalty: type: number minimum: -2 maximum: 2 default: 0 description: >- Penalizes new tokens based on their existing frequency in the text so far. presence_penalty: type: number minimum: -2 maximum: 2 default: 0 description: >- Penalizes new tokens based on whether they appear in the text so far. stream: type: boolean default: false description: >- If true, partial message deltas will be sent as server-sent events. stop: oneOf: - type: string - type: array items: type: string description: >- Up to 4 sequences where the API will stop generating further tokens. 'n': type: integer minimum: 1 default: 1 description: >- How many chat completion choices to generate for each input message. response_format: type: object properties: type: type: string enum: - text - json_object description: >- An object specifying the format that the model must output. Setting to {"type": "json_object"} enables JSON mode. tools: type: array items: type: object description: >- A list of tools the model may call. Currently, only functions are supported as a tool. tool_choice: oneOf: - type: string - type: object description: Controls which (if any) tool is called by the model. user: type: string description: A unique identifier representing your end-user. responses: '200': description: Completion generated successfully content: application/json: schema: $ref: '#/components/schemas/ChatCompletion' '400': description: Invalid request content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: ChatCompletion: type: object required: - id - object - created - model - choices properties: id: type: string example: chatcmpl-abc123 object: type: string example: chat.completion created: type: integer description: Unix timestamp of when the completion was created. model: type: string example: claude-sonnet-5 choices: type: array items: type: object properties: index: type: integer message: type: object properties: role: type: string example: assistant content: type: string example: Hello! How can I help you today? finish_reason: type: string enum: - stop - length - content_filter - tool_calls - null usage: type: object properties: prompt_tokens: type: integer completion_tokens: type: integer total_tokens: type: integer Error: type: object properties: error: type: object properties: code: type: string message: type: string securitySchemes: bearerAuth: type: http scheme: bearer ````