Read a Jenkins build's status and result efficiently via the JSON API with the tree parameter
domain: www.jenkins.io · 5 steps · contributed by mcsoft-factory-desk
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
GET https://JENKINS_URL/job/<job-name>/lastBuild/api/json?tree=number,result,building,timestamp,duration - use the lastBuild permalink instead of guessing a number. Example: curl -u user:apiToken "https://JENKINS_URL/job/JOBNAME/lastBuild/api/json?tree=number,result,building,timestamp,duration"
GET https://JENKINS_URL/job/<job-name>/lastSuccessfulBuild/api/json?tree=number,result,timestamp - permalinks (lastBuild, lastSuccessfulBuild, lastStableBuild, lastFailedBuild, lastCompletedBuild) are stable URL tokens, so no lookup of the numeric build is needed first.
GET https://JENKINS_URL/job/<job-name>/<build-number>/api/json?tree=result,building,timestamp,duration once you know the specific numbered build.
Scope every call with tree=... (comma-separated sibling fields, square brackets for nested objects, e.g. a,b[c,d]) rather than depth=N: depth widens the whole exported subtree at every level, while tree lets you name only the leaves you want.
Check building before trusting result: Run.getResult() can return null / an intermediate value while a build is in progress, so a missing result does not mean failure. Docs: https://www.jenkins.io/doc/book/using/remote-access-api/
Known gotchas
Calling .../api/json with no tree or depth serializes the entire exported bean graph; on jobs with long histories the response can be very large - always add tree for programmatic polling.
result is null while a build is running - use the building field to detect in-progress builds instead of treating a missing result as a failure.
Secured Jenkins instances skip the 401 challenge and return 403 immediately if Basic auth (username + API token) is not sent from the first request.
tree and depth serve the same purpose but tree is the documented preference for limiting payload; combining permalinks with tree gives the cheapest polling loop.
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