422 Unprocessable Content

What 422 means

Formerly "Unprocessable Entity" (from WebDAV). The server parsed the request fine but the content fails validation: an end date before a start date, a negative quantity, a reference to an id that does not exist.

Rails, Django REST Framework and many API styles return 422 for validation errors with a body listing each field problem.

Common causes

• Business-rule validation failures.
• Well-formed JSON with wrong types or missing required fields, depending on API convention.

How to fix it

• Return a structured error body with field paths and messages.
• Clients should show the messages to the user rather than retrying.

What it looks like

A typical response:

HTTP/1.1 422 Unprocessable Content
Content-Type: application/json

{"errors":[{"field":"end_date","message":"must be after start_date"}]}

The same event in an nginx access log (the status is the number after the request line):

203.0.113.7 - - [10/Sep/2026:10:12:01 +0000] "POST /api/orders HTTP/1.1" 422 153 "-" "Mozilla/5.0"

Check it with curl

-i prints the status line and headers, and -w '%{http_code}' prints only the number, which is handy in scripts and health checks. Replace the URL with yours:

curl -i -X POST -H 'Content-Type: application/json' -d '{"a":1}' https://example.com/api/orders

Compare what curl sees with what the browser sees. A different status from the same URL usually means a cache, a CDN edge or a cookie is in the way.

Investigating a run of 422s? Paste the log excerpt into Log Share to get line numbers, highlighting and an expiring link for whoever is on call with you.

Related status codes

• 400Bad Request: The server could not understand the request because it is malformed.
• 409Conflict: The request conflicts with the current state of the resource.
• 415Unsupported Media Type: The request body is in a format the server does not accept.

FAQ