Core C APIs

The core NGINX C APIs expose the internal types, structures, and functions that modules use to:

• Integrate with the master/worker process model
• Hook into the HTTP / mail / stream subsystems
• Allocate memory, log events, and schedule timers

This section is based on the historical Module API documentation from the original NGINX Wiki, restructured as Markdown for MkDocs.

It is organised as:

• Module API: high-level overview and table of contents
• Main module API: types and structures in the main module context
• Event handling API: working with the event loop
• HTTP API: HTTP-specific types, headers, requests, responses, and helpers
• Mail API: mail subsystem structures and hooks