Free resource
The Senior Frontend Engineer Checklist
20 things I learned building production React applications
A practical checklist for senior frontend engineers — architecture, components, state, testing, migrations, and team practices from real production work.
20 checkpoints
01.
Architecture & structure
- Define folder boundaries before adding new abstractions
- Keep feature code colocated; share only what is truly reusable
- Treat API and auth layers as platform concerns, not per-page logic
- Document where new code belongs so the team does not guess
02.
Components & design systems
- Build shared UI primitives in Storybook with documented states
- Separate presentational components from business logic
- Design components for accessibility from the first PR, not as a follow-up
- Version shared modules when multiple apps depend on them
03.
State & data
- Default to local state; escalate only when sharing is necessary
- Use dedicated server-state tooling for API data (not a global store)
- Avoid a single global store that becomes a catch-all
- Model permissions and roles explicitly in the UI layer
04.
Quality & delivery
- Test auth flows, permissions, and high-traffic user paths first
- Run static analysis (e.g. SonarQube) in CI for every merge
- Make code review about maintainability, not style preferences
- Measure cycle time and defects — not vanity coverage percentages
05.
Migrations & scale
- Migrate legacy screens incrementally with clear parity criteria
- Introduce TypeScript in strict islands before going wide
- Use AI tooling to accelerate review — not to skip architecture thinking
- Optimize for team velocity six months from now, not demo day