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Format Conversion

Openference supports three wire formats:
  • OpenAI (chat/completions, responses, embeddings)
  • Anthropic (messages)
  • Gemini (via OpenAI compatibility layer on many routes)

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Passthrough vs conversion

When the model route is configured with the exact format you send, we pass the body through unchanged (best performance and fidelity). When formats differ, we convert:
  • OpenAI ↔ Anthropic (full messages, tool calls, system prompts, streaming events)
  • Gemini is usually reached via its OpenAI-compatible surface

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What is preserved

  • Roles and content
  • Tool / function calling roundtrips
  • System instructions (mapped to system for Claude)
  • Sampling parameters
  • Streaming event shapes (converted to the client-expected format)

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What to expect

You can use your preferred client SDK and model ID without caring which upstream serves it. If a capability (e.g. vision, specific tool schema) is supported by the upstream model, it will work. See the source of truth for any given model on the Models page.