Loading balance requests between processes.Spawning multiple processes and/or threads of applications.Translating requests to application code.Listening for requests (HTTP, FastCGI, uWSGI, and more).Here’s what the common functionality of a gateway entails: Some call themselves process managers, some call themselves HTTP servers. The exact definition of a gateway is somewhat fluid. It accepts requests from a web server and translates them for a web application. The gateway sits between a web server (Nginx, Apache) and a web application. For your WordPress website, the web application is your WordPress installation which is coded in PHP. It typically has tools to handle HTTP requests. In the picture below you can see the PHP modern web application workflow.Ī web application is application software that can be coded in different programming languages and can use specific frameworks or libraries. Let’s first discuss how hosting a modern web application works.

What does 502 Bad Gateway mean?īefore we define what a 502 Bad Gateway error is, let’s deep-dive into server infrastructure and find out the meaning of some terms, like web server, proxy server or gateway, and upstream server. In this article, we’ll come to understand what a 502 Bad Gateway error is, talk about the reasons for a 502 Bad Gateway error, and explore some tips for troubleshooting this type of errors. In my previous article, we’ve already discussed the causes of a 504 Gateway Timeout error and possible solutions for it. HTTP 504 Gateway Timeout and HTTP 502 Bad Gateway errors are the most common server errors for WordPress website visitors and owners.

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