Anthropic API 504 timeout_error: what it means and how to fix it

What it means

The request timed out while processing.

Causes

• Long-running non-streaming requests, for example a large max_tokens without streaming
• Networks dropping idle connections

How to fix it

1. 1
   Fix 1.

   Use the streaming Messages API for long-running requests, or the Message Batches API to poll for results instead of holding an uninterrupted connection.

2. 2
   Fix 2.

   Avoid setting a large max_tokens value without streaming. The SDK can consume the stream and return the complete Message object.

   Snippet

   Copy

   with client.messages.stream(
       max_tokens=128000,
       messages=[{"role": "user", "content": "Write a detailed analysis..."}],
       model="claude-sonnet-5",
   ) as stream:
       message = stream.get_final_message()

3. 3
   Fix 3.

   For direct API integrations, set a TCP socket keep-alive to reduce the impact of idle connection timeouts.