HTTP

HTTP 302 Found vs 502 Bad Gateway

HTTP 302 (Found) is a 3xx Redirection response, while 502 (Bad Gateway) is a 5xx Server Error response. 302 indicates that the resource temporarily resides at a different URL. The client should continue using the original URL for future requests. In contrast, 502 means that the server, acting as a gateway or proxy, received an invalid response from the upstream server.

Description

The resource temporarily resides at a different URL. The client should continue using the original URL for future requests.

When You See It

During A/B testing, temporary maintenance pages, or geo-based redirects.

How to Fix

Follow the Location header. Note: browsers may change POST to GET on redirect.

Description

The server, acting as a gateway or proxy, received an invalid response from the upstream server.

When You See It

When Nginx/Apache can't reach the application server (e.g., Gunicorn is down, upstream timeout).

How to Fix

Check if the upstream server is running. Verify proxy configuration. Check for upstream timeouts.

Key Differences

1.

302 is a 3xx Redirection response, while 502 is a 5xx Server Error response.

2.

HTTP 302: The resource temporarily resides at a different URL. The client should continue using the original URL for future requests.

3.

HTTP 502: The server, acting as a gateway or proxy, received an invalid response from the upstream server.

4.

You encounter 302 when during A/B testing, temporary maintenance pages, or geo-based redirects.

5.

You encounter 502 when when Nginx/Apache can't reach the application server (e.g., Gunicorn is down, upstream timeout).

When to Use Which

For 302 (Found): Follow the Location header. Note: browsers may change POST to GET on redirect. For 502 (Bad Gateway): Check if the upstream server is running. Verify proxy configuration. Check for upstream timeouts.

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