DeepSeek Chat Completions Require Full History Replay

What we verified on June 27, 2026

• DeepSeek's official multi-round conversation guide says /chat/completions is stateless: the server does not keep prior turn context for you.
• The official fix is explicit rather than implied: each later request must concatenate all previous conversation history and send it back to the API.
• DeepSeek's own example appends the assistant response from round one before sending round two, then adds the next user question after that.
• The published sample still uses the ordinary OpenAI-compatible route with base_url=https://api.deepseek.com and model=deepseek-v4-pro, which means this is not a special SDK-only edge case.
• The guide makes the support boundary clearer for production apps: if a follow-up answer looks forgetful, the first debugging target is usually the caller's messages replay, not a hidden DeepSeek memory failure.

Sources

• DeepSeek English homepage
• DeepSeek official multi-round conversation guide
• DeepSeek official JSON Output guide
• DeepSeek official change log
• DeepSeek official status page
• DeepSeek official GitHub organization
• DeepSeek official Hugging Face organization
• DeepSeek official X account surface