HTTP 401 Unauthorized
Client failed to provide valid credentials (e.g. missing, expired, or corrupted Bearer JWT token).
4xx Client Errors
RFC 9110 Section 15.5.2
Test endpoint:
curl -i -X GET https://httpbin.org/status/401 ⚠️ Common Causes
- • Missing Authorization header in request
- • Expired or revoked JWT access token
🛠️ How to Fix / Developer Actions
- ✓ Refresh session credentials using a refresh token or re-login
- ✓ Inspect JWT payload in a decoder to verify expiration claims
Open the full tool: Convert cURL to Fetch, Python, or Go →
Status Reference & Causes
4xx Client Errors Status Codes Table
| Код | Название | RFC |
|---|---|---|
| 400 | Bad Request | RFC 9110 Section 15.5.1 |
| 401 | Unauthorized | RFC 9110 Section 15.5.2 |
| 403 | Forbidden | RFC 9110 Section 15.5.4 |
| 404 | Not Found | RFC 9110 Section 15.5.5 |
| 405 | Method Not Allowed | RFC 9110 Section 15.5.6 |
| 408 | Request Timeout | RFC 9110 Section 15.5.9 |
| 409 | Conflict | RFC 9110 Section 15.5.10 |
| 410 | Gone | RFC 9110 Section 15.5.11 |
| 418 | I'm a teapot | RFC 2324 / RFC 9110 Section 15.5.19 |
| 422 | Unprocessable Content | RFC 9110 Section 15.5.21 |
| 429 | Too Many Requests | RFC 6585 Section 4 |
FAQ
What does HTTP 401 Unauthorized mean?
Client failed to provide valid credentials (e.g. missing, expired, or corrupted Bearer JWT token). It is defined in RFC 9110 Section 15.5.2 as a 4xx Client Errors status code.
Is HTTP 401 an error on client or server side?
HTTP 401 is a client-side error (4xx), meaning the request itself was invalid, unauthorized, or malformed.
How can I test an HTTP 401 response in terminal?
You can use cURL with the -I flag to fetch headers only: curl -I https://httpbin.org/status/401