fullstack-software-engineer

name

fullstack-software-engineer

description

Guides full-stack software engineering—end-to-end product features across web frontends (React/Next.js or similar), backend APIs (Node/TypeScript or Python), databases, auth, testing, and production debugging for maintainable application code. Use when building or fixing user-facing features, designing REST/GraphQL/tRPC contracts, implementing forms and API routes, writing migrations, adding tests, or reviewing application PRs—not for CI/CD platforms (devops), cloud VPC/IaC (infrastructure-engineer), data warehouse modeling (data-warehouse-engineer), LLM/RAG features (ai-engineer), or org security/compliance programs (cybersecurity, compliance-engineer). For browser web-app patterns (sessions, CSRF, CORS, CSP, SSR/SPA routing), use web-application-developer. For senior-level system design and mentorship-style review, also use senior-fullstack-developer. UI-only from design: ui-software-engineer. Ticket repro without code: support-engineer.

Full Stack Software Engineer

When to Use

• Implement a vertical feature (UI + API + persistence)
• Design or change an API consumed by the frontend
• Fix bugs spanning client and server
• Add auth, validation, pagination, or file upload flows
• Write or extend unit, integration, and critical-path e2e tests

When NOT to Use

• Pipeline, GitOps, or cluster operations → devops or platform-engineer
• Terraform, networking, or K8s cluster design → infrastructure-engineer
• Security program, audit evidence, or SOC work → cybersecurity, compliance-engineer
• Deep service architecture RFCs across many teams → senior-software-engineer
• Explicit senior full-stack leadership scope → senior-fullstack-developer

Related skills

Need	Skill
Senior slice delivery and deeper review bar	senior-fullstack-developer
RFCs and cross-service design	senior-software-engineer
Deploy and observability plumbing	devops
Requirements and acceptance criteria	business-analyst
User-facing docs	tech-writer-researcher
Front-end-only architecture and a11y	senior-frontend-software-engineer
Web sessions, CSRF, CORS, hybrid rendering	web-application-developer
Customer ticket repro and escalation	support-engineer

Core Workflows

1. Vertical feature delivery

1. Confirm acceptance criteria and edge cases (empty, error, permissions)
2. Define API contract and UI states
3. Implement server: validation, authz, persistence, migrations
4. Implement client against typed contract
5. Test: unit (logic), integration (API), e2e (happy path)
6. Add logging/metrics on new paths; feature flag if risky

See references/feature_delivery.md for checklist.

2. API and database

Concern	Default
Validation	Schema at boundary (Zod, Pydantic)
Auth	Session or JWT; check authz per resource
Queries	Avoid N+1; index for access patterns
Mutations	Transactions where needed; idempotency keys for payments-like flows
Errors	Stable codes; no internal details to clients

See references/api_and_database.md for pagination and migrations.

3. Frontend integration

• Match loading/error/empty states to design
• Prefer server fetch for read-heavy pages when using Next.js App Router
• Client components only for interactivity
• Accessible forms (labels, focus, keyboard)

See references/frontend_integration.md for forms and caching.

4. Testing and PR hygiene

• Lint and typecheck clean
• Tests cover changed behavior, not only happy path
• No secrets in repo; env via configuration
• Small PRs; describe rollout and rollback

See references/testing_debugging.md for test pyramid.

5. Production debugging

1. Reproduce with correlation ID or request ID
2. Check deploys, flags, and recent config changes
3. Trace: logs → metrics → DB slow queries
4. Fix with regression test; hotfix or rollback per severity

See references/testing_debugging.md for common failures.

When to load references

• Feature flow → references/feature_delivery.md
• APIs and DB → references/api_and_database.md
• UI integration → references/frontend_integration.md
• Tests and prod issues → references/testing_debugging.md