Direct JQL validation for custom JQL functions returns to Search REST APIs

We are reintroducing direct JQL query validation to the Search REST API (/rest/api/3/search/jql) specifically for queries that use custom JQL functions.

Previously, when the new Search REST API was introduced, JQL validation was moved exclusively to the parse endpoint (/rest/api/3/jql/parse). Based on developer feedback, we are bringing this capability back to the search endpoint for custom JQL functions.

If a JQL query containing custom JQL functions is invalid, malformed, or references unsupported functions or arguments, the search API will now return an immediate HTTP 400 Bad Request with detailed error messages. This change applies exclusively to custom JQL functions; native JQL queries and other general usages of the search endpoint remain unaffected and will continue to follow existing validation behaviors.

What you need to do

1. Simplify your integration: If your app uses custom JQL functions, you no longer need to make a separate pre-flight call to the JQL parse API (/rest/api/3/jql/parse) to validate these queries before searching.
2. Update error handling: Ensure your search API integrations are prepared to handle HTTP 400 Bad Request responses and can inspect the returned error messages when executing queries that include custom JQL functions.
3. Review documentation: For more information on constructing queries, refer to the Jira Search REST API documentation.