Skills Matrix

Q: Frontend senior but Node junior?

Title may stay "Senior Engineer" with Node track = Junior in matrix. Dual tracks prevent false expectations on first API on-call shift.

Junior → senior Node competencies for backend TypeScript teams. Use for leveling, growth plans, and interview rubrics - not tenure alone.

How to Use

Self-assess quarterly with manager; attach PR/incident evidence.
Hiring: score candidates per column; no single trick question.
Onboarding: map Frontend → Node Path to junior column gaps.

Competency Table

Competency	Junior	Mid	Senior
Runtime	Explains event loop; avoids sync blocking	Diagnoses loop stall from logs/metrics	Sets team policy on `uncaughtException`, worker split
HTTP/API	CRUD routes, Zod, 4xx/5xx standards	Pagination, auth middleware, idempotency keys	ADR on Fastify vs Nest; versioning strategy
Data	Parameterized queries; simple migrations	Transactions, indexes, N+1 awareness	Migration expand-contract; pool sizing
Async jobs	Enqueues job; understands retry	BullMQ worker, DLQ, concurrency tuning	Queue vs event bus ADR; backpressure design
Config/secrets	Uses `.env.example`; typed env module	Secrets manager integration	Rotation runbooks; fail-fast boot policy
Testing	`node:test` or Jest unit + inject	Integration tests with test DB	Contract tests; load test interpretation
Observability	Reads JSON logs with `jq`	Structured fields, requestId, metrics	SLO definition; alert tuning
Security	No secrets in git; basic auth	OWASP API top 10 in review	Threat modeling for new surfaces
CI/CD	Green local = same scripts as CI	Writes GitHub Actions job	Release train; canary/rollback decision
Linux ops	curl health, lsof port	kubectl logs, top during incident	IC on SEV2; runbook authorship
Git	Feature branch + PR template	Cherry-pick to release	Hotfix lane ownership
Leadership	Asks for pairing	Mentors one junior	Sprint capacity for tech debt; ADR facilitation

Junior: Expected Evidence

Merged PR with route + Zod + test (Fastify Basics)
Fixed EADDRINUSE with lsof without senior rescue
Explained why await matters in one code review comment
Ran npm ci && npm test before every push

Study path: Node.js Basics → zod → Onboarding Basics

Mid: Expected Evidence

Owned feature spanning API + migration + worker
Debugged pool exhaustion or slow query with metrics
Added BullMQ consumer with DLQ (Queue Worker Skill)
Reviewed PR with auth and SQL injection checklist

Study path: bullmq / ioredis → API Design Basics → Pairing on API PRs

Senior: Expected Evidence

Authored ADR adopted by team (framework, ORM, queue)
Led incident to resolution with rollback decision documented
Improved onboarding doc from hire feedback loop
Negotiated non-feature sprint capacity for LTS upgrade

Study path: Technical Leadership Best Practices → Incident Triage Skill → DORA Metrics for Node Teams

Growth Plan Template

## Q3 growth - Alex (Junior → Mid)
Current gap: transactions + BullMQ
Sprint 1: Pair on order checkout transaction PR
Sprint 2: Own email worker with DLQ
Evidence: merged PRs + retro notes
Review date: 2026-09-30

One competency focus per sprint - not "become senior"
Evidence = merged work, not courses completed

Promotion Signals (Mid → Senior)

Signal	Weak	Strong
Incidents	Waits for instructions	Runs IC checklist; documents timeline
Design	Implements spec only	Proposes ADR with tradeoffs
Review	LGTM on style	Catches auth, pool, PII issues
Scope	Single service	Cross-service release coordination

FAQs

Frontend senior but Node junior?

Title may stay "Senior Engineer" with Node track = Junior in matrix. Dual tracks prevent false expectations on first API on-call shift.

How many juniors per senior mentor?

1 senior : 2 juniors max for meaningful weekly pairing. Overflow hires wait or use group office hours.

Onboarding Basics - day-one setup
Frontend → Node Path - learning ramp
Pairing on API PRs - review depth
Team & Onboarding Best Practices - team norms

Node.js Learn Guides - Official learning path.
Node.js Best Practices (GitHub) - Curated production best practices.
The Odin Project – Node.js Path - Project-based full-stack curriculum including Node.js.
Node.js the Right Way - Server-side JavaScript fundamentals.
Get Programming with Node.js - Introductory programming with Node.js.

Stack versions: This page was written for Node.js 24.18.0 (Active LTS), npm 10+, TypeScript 5.6+, Express 5, Fastify 5, and NestJS 11.

Competency Table

Competency	Junior	Mid	Senior
Runtime	Explains event loop; avoids sync blocking	Diagnoses loop stall from logs/metrics	Sets team policy on `uncaughtException`, worker split
HTTP/API	CRUD routes, Zod, 4xx/5xx standards	Pagination, auth middleware, idempotency keys	ADR on Fastify vs Nest; versioning strategy
Data	Parameterized queries; simple migrations	Transactions, indexes, N+1 awareness	Migration expand-contract; pool sizing
Async jobs	Enqueues job; understands retry	BullMQ worker, DLQ, concurrency tuning	Queue vs event bus ADR; backpressure design
Config/secrets	Uses `.env.example`; typed env module	Secrets manager integration	Rotation runbooks; fail-fast boot policy
Testing	`node:test` or Jest unit + inject	Integration tests with test DB	Contract tests; load test interpretation
Observability	Reads JSON logs with `jq`	Structured fields, requestId, metrics	SLO definition; alert tuning
Security	No secrets in git; basic auth	OWASP API top 10 in review	Threat modeling for new surfaces
CI/CD	Green local = same scripts as CI	Writes GitHub Actions job	Release train; canary/rollback decision
Linux ops	curl health, lsof port	kubectl logs, top during incident	IC on SEV2; runbook authorship
Git	Feature branch + PR template	Cherry-pick to release	Hotfix lane ownership
Leadership	Asks for pairing	Mentors one junior	Sprint capacity for tech debt; ADR facilitation

Senior: Expected Evidence

Authored ADR adopted by team (framework, ORM, queue)

Led incident to resolution with rollback decision documented

Improved onboarding doc from hire feedback loop

Negotiated non-feature sprint capacity for LTS upgrade

Growth Plan Template

## Q3 growth - Alex (Junior → Mid)
Current gap: transactions + BullMQ
Sprint 1: Pair on order checkout transaction PR
Sprint 2: Own email worker with DLQ
Evidence: merged PRs + retro notes
Review date: 2026-09-30

One competency focus per sprint - not "become senior"

Evidence = merged work, not courses completed

Signal

Weak

Strong

Incidents

Waits for instructions

Runs IC checklist; documents timeline

Design

Implements spec only

Proposes ADR with tradeoffs

Review

LGTM on style

Catches auth, pool, PII issues

Scope

Single service

Cross-service release coordination

FAQs

Frontend senior but Node junior?

Title may stay "Senior Engineer" with Node track = Junior in matrix. Dual tracks prevent false expectations on first API on-call shift.

How many juniors per senior mentor?

1 senior : 2 juniors max for meaningful weekly pairing. Overflow hires wait or use group office hours.

Node.js Learn Guides - Official learning path.

Node.js Best Practices (GitHub) - Curated production best practices.

The Odin Project – Node.js Path - Project-based full-stack curriculum including Node.js.

Node.js the Right Way - Server-side JavaScript fundamentals.

Get Programming with Node.js - Introductory programming with Node.js.

Stack versions: This page was written for Node.js 24.18.0 (Active LTS), npm 10+, TypeScript 5.6+, Express 5, Fastify 5, and NestJS 11.

Skills Matrix

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Skills Matrix