API Reference

// Definitions of subtypes are below
type Request = {
  // Either "messages" or "prompt" is required
  messages?: Message[];
  prompt?: string;

  // If "model" is unspecified, uses the user's default
  model?: string; // See "Supported Models" section

  // Allows to force the model to produce specific output format.
  // See "Structured Outputs" section below and models page for which models support it.
  response_format?: ResponseFormat;

  stop?: string | string[];
  stream?: boolean; // Enable streaming

  // Plugins to extend model capabilities (PDF parsing, response healing)
  // See "Plugins" section: openrouter.ai/docs/guides/features/plugins
  plugins?: Plugin[];

  // See LLM Parameters (openrouter.ai/docs/api_reference/parameters)
  max_tokens?: number; // Range: [1, context_length)
  temperature?: number; // Range: [0, 2]

  // Tool calling
  // Will be passed down as-is for providers implementing OpenAI's interface.
  // For providers with custom interfaces, we transform and map the properties.
  // Otherwise, we transform the tools into a YAML template. The model responds with an assistant message.
  // See models supporting tool calling: openrouter.ai/models?supported_parameters=tools
  tools?: Tool[];
  tool_choice?: ToolChoice;

  // Advanced optional parameters
  seed?: number; // Integer only
  top_p?: number; // Range: (0, 1]
  top_k?: number; // Range: [1, Infinity) Not available for OpenAI models
  frequency_penalty?: number; // Range: [-2, 2]
  presence_penalty?: number; // Range: [-2, 2]
  repetition_penalty?: number; // Range: (0, 2]
  logit_bias?: { [key: number]: number };
  top_logprobs: number; // Integer only
  min_p?: number; // Range: [0, 1]
  top_a?: number; // Range: [0, 1]

  // Reduce latency by providing the model with a predicted output
  // https://platform.openai.com/docs/guides/latency-optimization#use-predicted-outputs
  prediction?: { type: 'content'; content: string };

  // OpenRouter-only parameters
  // See "Model Routing" section: openrouter.ai/docs/guides/features/model-routing
  models?: string[];
  route?: 'fallback';
  // See "Provider Routing" section: openrouter.ai/docs/guides/routing/provider-selection
  provider?: ProviderPreferences;
  user?: string; // A stable identifier for your end-users. Used to help detect and prevent abuse.

  // Debug options (streaming only)
  debug?: {
    echo_upstream_body?: boolean; // If true, returns the transformed request body sent to the provider
  };
};

// Subtypes:

type TextContent = {
  type: 'text';
  text: string;
};

type ImageContentPart = {
  type: 'image_url';
  image_url: {
    url: string; // URL or base64 encoded image data
    detail?: string; // Optional, defaults to "auto"
  };
};

type ContentPart = TextContent | ImageContentPart;

type Message =
  | {
      role: 'user' | 'assistant' | 'system';
      // ContentParts are only for the "user" role:
      content: string | ContentPart[];
      // If "name" is included, it will be prepended like this
      // for non-OpenAI models: `{name}: {content}`
      name?: string;
    }
  | {
      role: 'tool';
      content: string;
      tool_call_id: string;
      name?: string;
    };

type FunctionDescription = {
  description?: string;
  name: string;
  parameters: object; // JSON Schema object
};

type Tool = {
  type: 'function';
  function: FunctionDescription;
};

type ToolChoice =
  | 'none'
  | 'auto'
  | {
      type: 'function';
      function: {
        name: string;
      };
    };

// Response format for structured outputs
type ResponseFormat =
  | { type: 'json_object' }
  | {
      type: 'json_schema';
      json_schema: {
        name: string;
        strict?: boolean;
        schema: object; // JSON Schema object
      };
    };

// Plugin configuration
type Plugin = {
  id: string; // 'web', 'file-parser', 'response-healing', 'context-compression'
  enabled?: boolean;
  // Additional plugin-specific options
  [key: string]: unknown;
};