Overview
CI (Continuous Integration) and CD (Continuous Delivery/Deployment) are two connected stages of the same pipeline, not synonyms. CI focuses on automated testing of every code change as it merges, while CD focuses on automated deployment of that validated code into staging or production. Teams that only automate the first half often assume they have full ‘CI/CD’ when they’ve really just automated build-and-test.
Comparison Diagram
Comparison Table
| Aspect | CI (Continuous Integration) | CD (Continuous Delivery/Deployment) |
|---|---|---|
| Trigger | Code commit or push to a shared repository | A successful CI run producing a new build artifact |
| Core process | Compile, run unit/integration tests, static analysis | Package the artifact, provision environments, run deployment scripts |
| Primary output | A verified, mergeable build artifact | A running release in staging and/or production |
| Environment scope | Build server or ephemeral test environment | Staging and/or production environments |
| Human gate | None — fully automated on every commit | Optional manual approval (Delivery) or none (Deployment) |
| Release cadence | N/A — runs per commit, not a release event | Can range from multiple times a day to once per commit |
| Failure consequence | Blocks the merge; breaks the build for the team | Blocks or rolls back the release; production stays on the last good version |
| Primary goal | Catch integration bugs early, keep the main branch releasable | Get every releasable build to users quickly and safely |
Key Differences
- CI’s output is a verified build artifact, not a live release
- CD adds environment provisioning and deployment steps that CI never performs
- A CI failure blocks the merge; a CD failure blocks the rollout instead
- Continuous Delivery keeps a manual approval gate before production, while Continuous Deployment removes it
- CI runs on every single commit; CD can be throttled by environment or business readiness
When to Use Each
CI (Continuous Integration)
- Fast feedback on commits: CI gives every developer immediate signal on whether their change broke the build or existing tests.
- Enforcing a releasable main branch: CI keeps the trunk always in a mergeable, working state by rejecting broken commits before they combine.
- Catching integration bugs early: Running the full test suite on every merge surfaces conflicts between parallel changes before they compound.
CD (Continuous Delivery/Deployment)
- Automating environment rollout: CD removes manual, error-prone steps like provisioning servers or running migration scripts on release day.
- Shipping features quickly: CD (as Continuous Deployment) lets validated changes reach users within minutes of merging, without a release queue.
- Staged rollouts with sign-off: CD (as Continuous Delivery) keeps a human approval step for regulated or high-risk production releases.