Why am I receiving 520 status codes from my app?

A 520 status code means your app returned an invalid or empty response. This can happen when an app crashes while trying to receive an upload or trying to return a response larger than it has been configured to manage.

For example, Next.js apps can return a 520 status code when the app crashes while trying to a return a response size larger than 4 MB or when receiving a file upload larger than 1 MB. The crash usually occurs before any logs can be generated, making it difficult to diagnose.

Before deploying your app to production, we recommend checking your framework’s resource management settings such as memory allocation, request timeouts, maximum payload sizes, and maximum response size, and also error handling for configurations that don’t meet your app’s needs.

Related Topics

Why does my app not restart when it fails a health check?

If an app’s health check fails, the app currently does not restart. This is because App Platform does not currently support liveness probes. An app only automatically restarts if the app crashes or if its disk or RAM usage exceeds the its limits.

Where can I find the client IP address of a request connecting to my app?

You can find the client IP address of a request connecting to your app in the do-connecting-ip HTTP header.

Why is my app's database connection timing out?

Timeouts can be caused by high CPU utilization, so check your app’s CPU utilization and consider scaling your app.