LLM-Rosetta open-source library lets developers switch between OpenAI, Anthropic, and Google AI APIs without rewriting code

A Python developer released LLM-Rosetta, a free, zero-dependency library that converts API requests and responses between OpenAI, Anthropic, Google GenAI, and compatible servers like Ollama. Instead of writing separate conversion code for every provider pair (a problem that grows exponentially as you add providers), LLM-Rosetta converts everything through a single shared format called an Intermediate Representation.

The library handles the full conversation flow — text messages, images, tool calls, and streaming responses all work across providers. A developer can start a conversation with OpenAI, switch mid-stream to Google, and the full chat history carries over without reformatting. This eliminates the manual work of learning and maintaining four different API specifications.

For teams building multi-LLM applications, this cuts deployment risk and lock-in. You can experiment with cheaper providers (like Ollama running locally) or swap to a different vendor if pricing changes, without touching your application code. Developers can install it with a single `pip install llm-rosetta` command and start converting between providers in minutes.