Code Review Process Sequence Diagram Template

A code review sequence diagram visualizes the ordered interactions between the key actors in a pull request workflow — typically the author, reviewers, CI/CD systems, and the version control platform. This template traces every step from the moment a developer opens a PR, through automated checks, reviewer feedback cycles, requested changes, approvals, and finally the merge event. By laying out these interactions chronologically across swimlanes, the diagram makes implicit team conventions explicit and gives everyone a shared mental model of how code moves from a feature branch into the main codebase.

## When to Use This Template

This template is especially valuable when onboarding new engineers who need to understand your team's review culture quickly, or when your team is standardizing a previously informal process. It's also useful during retrospectives when you want to identify bottlenecks — for example, spotting that review requests consistently stall at a particular step. Engineering managers, DevOps leads, and senior developers will find it practical for documenting review SLAs, defining required approvals, and aligning distributed teams across time zones on expected turnaround behavior.

## Common Mistakes to Avoid

One frequent mistake is modeling only the happy path — the straight line from PR open to merge — while omitting the change-request loop that represents the majority of real-world reviews. Make sure your diagram includes at least one cycle back to the author for revisions. Another pitfall is over-crowding the diagram with every possible edge case, such as draft PRs, force pushes, or rebase conflicts, in a single view; consider separate diagrams for exception flows. Finally, avoid labeling actors too generically. Using "Reviewer" instead of distinguishing between a required code owner and an optional peer reviewer obscures accountability. Precise actor naming makes the diagram actionable rather than decorative, and ensures it remains a reliable reference rather than a document that gets ignored after its first week.