---
title: "422 Unprocessable Content — what it means and how to fix it"
description: "The request is well-formed and understood, but the data in it fails the rules. What causes an HTTP 422, what to try as a visitor, and what to check if it is your own site."
url: https://atoneplace.net/error/422/
site: "At One Place"
---

# HTTP 422 — Unprocessable Content

**HTTP 422: Unprocessable Content**

The request is well-formed and understood, but the data in it fails the rules.

## What 422 actually means

The syntax is fine — the JSON parsed, the fields are the right types — but the content does not make sense to the application. An end date before a start date, an email address that is not an address, a quantity of −3. This is the precise code for validation failures, where 400 says only "I could not parse this". It originated in WebDAV but is now the convention across most modern APIs.

## Common causes

- Field-level validation failed on otherwise valid JSON
- A required business rule violated, such as an end date before a start date
- A referenced ID that does not exist
- A value outside an allowed range or enumeration
- Semantic errors in a WebDAV XML request body

## If you're just trying to view the page

1. Check the form for a field-level error message — the site usually highlights what was wrong
2. Look for values that are individually plausible but inconsistent, like dates in the wrong order
3. Re-enter data that was pasted; invisible characters from other applications often cause this

## If it's your site

1. Return a structured list of which fields failed and why; a bare 422 is barely better than a 400
2. Use 422 for validation and keep 400 for genuinely unparseable requests — the distinction is the point
3. Do not use 422 for authorisation problems; that is 403
4. Make sure your validation errors are stable enough for clients to map to their own UI strings

## Reference

- **Status code:** 422
- **Reason phrase:** Unprocessable Content
- **Category:** 4xx — Client Error
- **Defined in:** RFC 9110 §15.5.21

## Common questions

### What does HTTP 422 mean?

The request is well-formed and understood, but the data in it fails the rules. The syntax is fine — the JSON parsed, the fields are the right types — but the content does not make sense to the application. An end date before a start date, an email address that is not an address, a quantity of −3.

### How do I fix a 422 error?

Check the form for a field-level error message — the site usually highlights what was wrong

### Is 422 a client error or a server error?

422 is in the 4xx range, which means client error. The request itself was the problem, so retrying it unchanged will usually return the same code.

## Related pages

- [404 Not Found](https://atoneplace.net/error/404/)
- [403 Forbidden](https://atoneplace.net/error/403/)
- [401 Unauthorized](https://atoneplace.net/error/401/)
- [429 Too Many Requests](https://atoneplace.net/error/429/)
- [400 Bad Request](https://atoneplace.net/error/400/)
- [413 Content Too Large](https://atoneplace.net/error/413/)
- [405 Method Not Allowed](https://atoneplace.net/error/405/)
- [409 Conflict](https://atoneplace.net/error/409/)
- [415 Unsupported Media Type](https://atoneplace.net/error/415/)
- [408 Request Timeout](https://atoneplace.net/error/408/)
- [410 Gone](https://atoneplace.net/error/410/)
- [451 Unavailable For Legal Reasons](https://atoneplace.net/error/451/)

## Sources

- Hypertext Transfer Protocol (HTTP) Status Code Registry — IANA (https://www.iana.org/assignments/http-status-codes/)
- RFC 9110: HTTP Semantics — IETF (https://www.rfc-editor.org/rfc/rfc9110.html)