HTTP 422 Unprocessable Entity
The request was well-formed (parsed fine) but failed semantic validation.
What it means
422 is what you return when the JSON parses, the types are right, but the business rules say no. A signup form where the email is already taken. A money transfer where the amount exceeds the balance. A scheduled job where the time is in the past.
Many APIs conflate 400 and 422. The cleaner convention: 400 = couldn't parse / wrong shape; 422 = parsed fine, but the request violates a business rule. The 422 response body typically includes per-field error messages.
Common causes
- Validation failed on a registered email / username
- State-machine violation (e.g. invoice already paid)
- Quota or rate-limit semantically failing
- Invariant violated (e.g. start time after end time)
How to fix it
- 1Inspect the response body — most APIs return field-level error messages
- 2Adjust the request payload to satisfy the business rules
How Uptimera reports 422
Uptimera flags 422 as down by default. For monitors that intentionally send the same payload (and thus would always 422 on a stateful endpoint), choose a stateless health endpoint instead.
Catch 422s before your customers do
Uptimera monitors your URLs from multiple regions and alerts the moment a 422 starts firing. Free plan included.