Code Review Process,
as a sequence diagram.
A sequence diagram template mapping the full PR lifecycle from open to merge, ideal for dev teams documenting code review workflows and onboarding engineers.
About this
specimen.
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.
Code Review Process, as another form.
- →FlowchartCode Review Process as a Flowchart
- →Class DiagramCode Review Process as a Class Diagram
- →State DiagramCode Review Process as a State Diagram
- →ER DiagramCode Review Process as a ER Diagram
- →User JourneyCode Review Process as a User Journey
- →Gantt ChartCode Review Process as a Gantt Chart
- →Mind MapCode Review Process as a Mind Map
- →TimelineCode Review Process as a Timeline
- →Git GraphCode Review Process as a Git Graph
- →Requirement DiagramCode Review Process as a Requirement Diagram
- →Node-based FlowCode Review Process as a Node-based Flow
- →Data ChartCode Review Process as a Data Chart
More sequence diagram
templates.
- Fig. 02┼Hiring PipelineA sequence diagram template mapping every hiring stage from sourcing to offer, ideal for HR teams, recruiters, and talent acquisition leads.
- Fig. 03┼Agile Sprint CycleA sequence diagram template mapping the Agile sprint cycle—planning, building, review, and retrospective—ideal for Scrum teams and Agile coaches.
- Fig. 04┼Change ManagementA sequence diagram template mapping the propose, review, schedule, and deploy stages of change management, ideal for IT teams and change managers.
- Fig. 05┼Employee OnboardingA sequence diagram template mapping day-one through 90-day onboarding milestones, ideal for HR teams and managers designing structured new-hire workflows.
- Fig. 06┼Customer Support TriageA sequence diagram template showing ticket intake to resolution flow, ideal for support teams, developers, and CX designers mapping triage workflows.
Common
questions.
- 01What actors should I include in a code review sequence diagram?
- At minimum, include the PR Author, one or more Reviewers, your CI/CD system (e.g., GitHub Actions or Jenkins), and the Version Control Platform (e.g., GitHub or GitLab). Add a Code Owner actor separately if your team enforces CODEOWNERS-based approvals.
- 02How do I show the change-request and revision loop in a sequence diagram?
- Use a combined fragment with the 'loop' or 'alt' operator to wrap the review-feedback and author-revision steps. This clearly signals that the cycle can repeat multiple times before an approval is granted.
- 03Can this sequence diagram replace written PR process documentation?
- It works best as a visual companion to written docs, not a replacement. The diagram communicates order and responsibility at a glance, while written documentation captures rationale, edge cases, and policy details that don't fit neatly into a sequence flow.
- 04How granular should each step in the PR sequence diagram be?
- Aim for steps that represent a distinct handoff or decision point — such as 'CI checks pass,' 'Reviewer requests changes,' or 'Author pushes fix.' Avoid logging every Git command or API call, which creates noise and makes the diagram hard to read.