Your prompt will be processed by a meta-model and routed to one of dozens of models (see below), optimizing for the best possible output. To see which model was used, visit Activity, or read the `model` attribute of the response. Your response will be priced at the same rate as the routed model. Learn more, including how to customize the models for routing, in our docs. Requests will be routed to the following models: - anthropic/claude-haiku-4.5 - anthropic/claude-opus-4.6 - anthropic/claude-sonnet-4.5 - anthropic/claude-sonnet-4.6 - deepseek/deepseek-r1 - google/gemini-2.5-flash-lite - google/gemini-3-flash-preview - google/gemini-3-pro-preview - google/gemini-3.1-pro-preview - meta-llama/llama-3.3-70b-instruct - minimax/minimax-m2.5 - mistralai/codestral-2508 - mistralai/mistral-7b-instruct-v0.1 - mistralai/mistral-large - mistralai/mistral-medium-3.1 - mistralai/mistral-small-3.2-24b-instruct-2506 - moonshotai/kimi-k2-thinking - moonshotai/kimi-k2.5 - openai/gpt-5 - openai/gpt-5-mini - openai/gpt-5-nano - openai/gpt-5.1 - openai/gpt-5.2 - openai/gpt-5.2-pro - openai/gpt-5.3-chat - openai/gpt-oss-120b - perplexity/sonar - qwen/qwen3-235b-a22b - x-ai/grok-3 - x-ai/grok-3-mini - x-ai/grok-4 - x-ai/grok-4.1-fast - z-ai/glm-5

Transform your natural language requests into structured OpenRouter API request objects. Describe what you want to accomplish with AI models, and Body Builder will construct the appropriate API calls. Example: "count to 10 using gemini and opus." This is useful for creating multi-model requests, custom model routers, or programmatic generation of API calls from human descriptions. BETA NOTICE: Body Builder is in beta, and currently free. Pricing and functionality may change in the future.

The simplest way to get free inference. openrouter/free is a router that selects free models at random from the models available on OpenRouter. The router smartly filters for models that support features needed for your request such as image understanding, tool calling, structured outputs and more.