claude api stream interrupted error

When streaming responses from Claude using Server-Sent Events (SSE), you may find that the connection abruptly drops midway through a completion. This issue is typically caused by aggressive network timeouts, proxy configurations, or unhandled exceptions in your chunk parsing loop. Below is a step-by-step troubleshooting guide to stabilise your API streams.

Check your client-side read timeout limits

By default, many HTTP client libraries (such as requests in Python or axios in Node.js) have short default read timeouts. Because Claude can take a few seconds to begin streaming the first chunk under heavy load, your client might terminate the connection prematurely. Increase your read timeout to at least 60 seconds to allow the stream buffer to establish successfully.

Implement automatic reconnection logic for SSE

Streams can drop due to minor network fluctuations. If you are consuming raw Server-Sent Events, ensure your subscriber loop catches disconnection exceptions and handles them. Always log the last received event ID. If you need to restart the request, you can resume gracefully rather than leaving your user with an incomplete block of text.

Validate JSON chunk parsing in custom implementations

If you are not using the official Anthropic SDK, you must manually parse the stream lines starting with data:. A common mistake is assuming every line contains a complete JSON payload. If the stream splits a single JSON message across two network packets, your parser will crash. Use a dedicated SSE parser library or buffer the incoming stream lines properly before passing them to your JSON decoder.

Check the Claude status for service outages

Sometimes the problem does not lie with your code but with Anthropic's regional gateway servers. If the system is overloaded, streams are frequently terminated early by the server. If you suspect an outage, read our guide on how to diagnose an Anthropic API 529 overloaded error to see if backend congestion is causing your stream interruptions.

Adjust keep-alive headers on reverse proxies

If your application sits behind a reverse proxy like Nginx, Cloudflare, or AWS ALB, the proxy may be closing idle connections. Configure your proxy to support long-lived HTTP connections by raising the keep-alive timeout. Ensure that buffering is disabled so that chunks are delivered to the client immediately instead of waiting for a full buffer load.