Middleware

Middleware functions run before route handlers on every request. They can modify the request, add context, or return early responses.

├── server/
│   └── middleware/
│       └── auth.ts
├── nitro.config.ts
├── package.json
├── README.md
├── server.ts
├── tsconfig.json
└── vite.config.ts

Defining Middleware

Create files in server/middleware/. They run in alphabetical order:

import { defineMiddleware } from "nitro/h3";

export default defineMiddleware((event) => {
  event.context.auth = { name: "User " + Math.round(Math.random() * 100) };
});

Middleware can:

• Add data to event.context for use in handlers
• Return a response early to short-circuit the request
• Modify request headers or other properties

Accessing Context in Handlers

Data added to event.context in middleware is available in all subsequent handlers:

import { defineHandler } from "nitro/h3";

export default defineHandler((event) => ({
  auth: event.context.auth,
}));

Learn More

• Routing