Nginx & PHP
Trace requests through server blocks, location matching, FastCGI parameters, and PHP-FPM pools. Complete configuration context matters more than a detached snippet. Use the documentation for the installed versions, test the configuration before reload, and preserve a known-good copy with a defined rollback path.
Nginx 502 Bad Gateway with PHP-FPM: 6 Causes and Fixes
A 502 Bad Gateway on Nginx with PHP-FPM means Nginx received the request but got no valid response from PHP-FPM.
FastCGI Cache, Varnish, or Application Cache: Which Layer for a PHP Site
Use Nginx FastCGI cache for shared PHP responses when Nginx already fronts the site and you can prove every personalized bypass.
Nginx Server Blocks: Host Multiple Sites on One Server
Nginx server blocks are configuration sections — each a server { } block — that let one Nginx instance host multiple websites on a single server.
PHP-FPM Tuning for Nginx: Pools and Worker Limits
PHP-FPM tuning starts with measurements, not a copied pm.max_children value.