How do I set HTTP headers in an Express application?

How do I set HTTP headers in an Express application?

You can set HTTP headers in an Express app using the res.set() method. For example: res.set('Content-Type', 'application/json');

Can I set multiple headers at once?

Yes, you can set multiple headers by passing an object to res.set(). For example: res.set({ 'Content-Type': 'application/json', 'Authorization': 'Bearer token' });

What if I want to set headers for all responses?

You can use middleware to set headers for all responses. For example:

app.use((req, res, next) => {
  res.set('X-Powered-By', 'MyApp');
  next();
});

Are there any headers I should avoid setting?

Yes, avoid setting headers that could interfere with the default behavior of the server, like Content-Length or Transfer-Encoding.