What Is a Release Candidate?
A release candidate is a build that is believed to be ready for release and is given final testing before it is declared the official release.
A release candidate, often abbreviated RC, is the "we think this is it" version. It is feature-complete and has passed the regular checks; the RC phase is the last opportunity to find blocking problems before it becomes the real release.
What it is
A release candidate is a specific build, often versioned like 2.0.0-rc.1, that a team intends to ship unless something serious is found. No new features are added at this point; only fixes for genuine release-blocking bugs. If the candidate survives validation, it is promoted to the final release.
How it is validated
The RC is deployed to a production-like environment and put through final testing: full regression suites, smoke tests, manual checks of high-risk areas, and sometimes a limited rollout to real users. The aim is to surface anything the normal pipeline missed before it affects everyone.
An example
A team tags v3.0.0-rc.1 and deploys it to staging for a final validation pass. Testers find a critical bug, so they fix it and cut rc.2. That one passes, and rc.2 is promoted, byte-for-byte, to become the official v3.0.0 release.
Why teams use it
The RC step provides a clean line between "probably ready" and "officially shipped." It gives a defined window for final, focused testing and a stable target to validate, instead of a moving one. If problems appear, you iterate on candidates rather than scrambling after a release.
Promote, do not rebuild
A key practice is that the final release is the exact same artifact as the validated candidate, just relabeled. Rebuilding for the release would discard the validation work, since you would be shipping something subtly different from what you tested.
Key takeaways
- A release candidate is a build believed ready, pending final testing.
- Only release-blocking fixes are made during the RC phase.
- The validated candidate is promoted unchanged to the final release.