HTTP 422 Unprocessable Content (previously Unprocessable Entity) means the server understands the request body format but cannot process the contained instructions. The syntax is correct but the content is semantically invalid — for example, validation errors on form fields.
Status
422 Unprocessable ContentExample
POST /contact HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0
Accept: text/html
Content-Type: application/x-www-form-urlencoded
name=&email=not-an-email&message=hiHTTP/1.1 422 Unprocessable Content
Content-Type: text/html; charset=utf-8
<!doctype html>
<html>
<body>
<h1>422 Unprocessable Content</h1>
<p>The form could not be submitted. Please check your entries and try again.</p>
</body>
</html>How to Troubleshoot
Check the response body for errors
The 422 response typically includes a list of specific validation errors.
Fix the request data
Correct the invalid fields based on the error messages and retry.
Validate against the API schema
Compare your request payload against the API's JSON Schema or documentation.
Common Causes
Validation errors
highThe request data fails server-side validation — required fields missing, values out of range, or invalid formats.
Business logic violation
mediumThe request violates business rules (e.g., transferring more money than the account balance).
Related Status Codes
References
| Specification | Section |
|---|---|
| HTTP Semantics | RFC 9110 §15.5.21 |
Frequently Asked Questions
This reference was compiled from official RFCs, protocol specifications, and hands-on troubleshooting experience. AI tools were used primarily for formatting and organizing the content on the page.