Open Responses
lastmod 2026-01-19created 2026-01-191 edits
An open specification for interoperability between LLMs
About
- An open-source specification and ecosystem aiming for interoperability across multiple LLM providers, defining a common interface based on the OpenAI Responses API
- Describes requests and responses with a shared schema, so they can run the same way across multiple model providers with minimal conversion work
- Organizes common components such as messages, tool calls, streaming, and multimodal input into a consistent structure, making it well suited for implementing agent workflows
- A structure that allows provider-specific extensions on top of a stable core, pursuing both extensibility and non-fragmentation
- Run as a community with many participating builders, including OpenRouter, Vercel, Hugging Face, LM Studio, Ollama, OpenAI, and vLLM