Code Review & Testing Checklist for SaaS & Startups

Target under 400 lines changed and split large refactors into sequenced PRs. Use GitHub size labels and WIP drafts to maintain reviewer focus and speed up cycle time.

Assign auto-reviewers for billing, authentication, and export/reporting paths. This routes changes to subject matter experts and avoids security or revenue-impacting mistakes.

Require linked issue, user impact, rollout plan, and a test checklist. For UI changes, include before/after screenshots or a short clip to cut review time.

Use patterns like feature/PROJ-123-short-slug and validate in CI. Clear naming improves traceability in audits and makes cross-team coordination easier.

Wrap non-trivial behavior behind flags via LaunchDarkly, Unleash, or ConfigCat and default to off. Add a kill switch and plan the cleanup task at merge.

Spin up ephemeral environments on Vercel/Netlify for frontends and Heroku Review Apps or k8s namespaces for services. Seed with synthetic tenant data to enable end-to-end validation.

Run ESLint, TypeScript strict mode, Pylint, or RuboCop on changed files with max warnings set to 0. This prevents tech debt from creeping into high-velocity codebases.

Gate merges on patch coverage (e.g., Codecov patch, Jest diff-coverage) rather than global metrics. This keeps new code well-tested without blocking on legacy gaps.

Use matrix builds across Node/Python versions and auto-cancel older pipelines on new commits. Faster feedback reduces context switching for small teams.

Leverage pnpm/npm/pip caches and Testcontainers reuse to trim minutes off every run. Savings compound for growth teams iterating dozens of times per day.

Run StrykerJS, mutmut, or PIT on billing, permissions, and pricing modules to reveal weak tests. Schedule weekly in CI to avoid slowing day-to-day PRs.

Use Prettier, Black, or gofmt with Husky or pre-commit to keep diffs clean. Clean diffs make reviews faster and reduce nitpicking.

Keep unit tests pure and under 200ms each with no network or database calls. This ensures quick feedback and easy debugging for product teams.

Use Testcontainers or Docker Compose for DBs, queues, and caches. Reset state between tests to prevent cross-test pollution and flakiness.

Adopt Pact or Pactflow to lock API expectations across microservices and third-party providers like Stripe. Break builds on incompatible changes before staging.

Use nock (JS), VCR (Ruby), or responses (Python) to avoid rate limits and random failures. Only allow real calls in a nightly suite if needed.

Generate tenants, users, roles, and subscriptions with seeded Faker data and fixed clocks. Avoid PII and lock user IDs to reduce flaky tests.

Auto-retry failed tests once, then quarantine and label persistently flaky cases. Report weekly flaky rate to drive root-cause fixes.

Run Semgrep or CodeQL tuned to your languages and frameworks and block on high severity findings. Startup teams catch critical issues without manual review overhead.

Use Dependabot or Renovate with Snyk or OSV-Scanner policy gates. Auto-merge safe upgrades and block vulnerable transitive dependencies.

Enable GitHub Advanced Security, Gitleaks, or TruffleHog pre-commit and in CI. Auto-revoke and rotate any exposed keys to contain blast radius.

Scan images with Trivy and Terraform with tfsec or Checkov, failing on CVEs above a set threshold. This keeps previews and staging safer by default.

Run OWASP ZAP baseline scans against ephemeral environments to catch obvious issues. Configure auth and exclude noisy paths to keep runs fast.

Statically check for PII logging and enforce structured logging filters and retention policies. Helps with GDPR and SOC 2 controls during audits.

Use online strategies (gh-ost, pt-online-schema-change) and expand-contract patterns. Plan roll-forward and verify long-running locks won’t degrade SLAs.

Run k6 or Locust smoke tests against hot endpoints with P95 latency limits. Fail the build when regressions exceed agreed budgets.

Set budgets for LCP, CLS, and color contrast and post reports on the PR. This keeps conversion-critical flows fast as the app grows.

Canary or blue-green deploys in staging with health checks and auto-rollback rules. Implement via Argo Rollouts or Spinnaker for predictable releases.

Require structured logs, metrics, and tracing spans via OpenTelemetry for new endpoints. Update dashboards and alerts before shipping to production.

Verify a runbook, on-call handoff, rate limits, and tested kill switches. Do not merge until all items are confirmed to reduce incident risk.