DevArbor
4xx Client Error

405 Method Not Allowed

What it means

The request method (GET, POST, PUT, DELETE, etc.) is known by the server but not allowed for the requested URL. The server must include an Allow header listing the permitted methods for the resource.

Site Visitor

What can I do?

  • If using a form, ensure it's set to the correct method (GET vs POST).
  • If the problem persists after retrying, contact the site owner.
Developer

How to debug & fix

  1. Include Allow header in 405 responses: Allow: GET, POST, OPTIONS
  2. Double-check your route definitions match the HTTP methods clients will use
  3. Add OPTIONS handler for CORS preflight if needed
  4. Include Allow: GET, POST, OPTIONS in every 405 response as required by RFC 9110.

Code Example

Node.js / Express
app.all('/read-only', (req, res, next) => {
  if (req.method !== 'GET') {
    return res.status(405)
      .set('Allow', 'GET')
      .json({ error: 'Method Not Allowed' });
  }
  next();
});

Related Status Codes

400 Bad Request 501 Not Implemented

How HTTP Status Codes Work

Every HTTP response carries a three-digit status code that tells the client — browser, API consumer, or search-engine crawler — exactly what happened. The first digit defines the class: 1xx informational (request in progress), 2xx success, 3xx redirection, 4xx client error (bad request, missing auth, not found), and 5xx server failure.

Status codes are standardised in RFC 9110 (HTTP Semantics, 2022). Extensions like WebDAV (RFC 4918) and rate-limit headers (RFC 6585) added codes beyond the core set. When a client receives an unrecognised code, the rule is to treat it as the generic x00 of its class.

Why the Right Code Matters

Semantically correct codes help search engines index accurately (301 passes link equity; 410 removes pages faster than 404), allow API clients to implement correct retry logic (429 + Retry-After, 503 + Retry-After), and let monitoring systems distinguish bugs (500) from load issues (503) from auth failures (401/403).

Looking up a different status code? The full reference covers all HTTP codes with causes, fix guides, and copyable code examples for Node.js and Python.

Browse the full HTTP Status Code reference →

Frequently Asked Questions

What does HTTP 405 Method Not Allowed mean?
The request method (GET, POST, PUT, DELETE, etc.) is known by the server but not allowed for the requested URL. The server must include an Allow header listing the permitted methods for the resource.
Is HTTP 405 the visitor's fault?
HTTP 405 Method Not Allowed is generally a client-side error, meaning the request itself has an issue. However, many causes — such as a broken link on the site or a misconfigured redirect — are the website owner's responsibility, not the visitor's.
How do I fix HTTP 405 Method Not Allowed?
As a visitor: check the URL for typos, go to the homepage, or search for the content. As a developer: include Allow header in 405 responses: Allow: GET, POST, OPTIONS.