Offer summary

Qualifications:

At least 5 years of experience building production back-ends with Node.js and TypeScript., Deep expertise in PostgreSQL performance tuning and AWS Aurora/RDS operations., Hands-on experience with Redis for caching and rate limiting., Practical knowledge of CI/CD processes using GitHub Actions and Docker..

Key responsibilities:

Profile and optimize slow database queries to improve performance.

Refactor ORM hotspots by using raw SQL, CTEs, or PL/pgSQL as needed.

Design and implement caching strategies and schema evolutions for scalability.

Mentor junior developers and enforce code quality standards.

Job description

The Opportunity

A growth-stage B2B / Saas / Data Platform client of ours processes ~10 k req/s and ~3 TB of relational data today; customer onboarding this quarter will push volumes 5–100×. Hotspots already appear in Sequelize‑generated queries, throttling Aurora PostgreSQL and driving up AWS spend.

Why Is this role open?

Our client needs a senior engineer who lives and breathes SQL performance to get them ahead of that curve (I.e. prep & plan to scale up data volumes immensely!).

Current Stack

Node.js (v16+) / TypeScript · Express.js · Sequelize ORM
Aurora PostgreSQL 15 primary, Redis/ElastiCache for low‑latency cache
AWS ECS Fargate · Docker · GitHub Actions CI/CD
Observability: New Relic, pg_stat_statements, auto_explain
Auth: JWT today, migration to Stytch planned Q4
Tests: Jest (unit, integration with Testcontainers‑Postgres)

What You’ll Do (Key Outcomes)

Profile & eliminate the top 10 slow queries; target p95 < 150 ms and 50 % CPU drop on RDS.
Refactor ORM hot‑spots – fall back to raw SQL, CTEs, lateral joins, or PL/pgSQL where warranted.
Evolve schema & data‑model: partitioning/ sharding, BRIN/GiST indexes, materialised views, retention/archive tables.
Design & implement caching strategy (Redis key design, TTL, invalidation hooks).
Protect throughput: connection pooling (PgBouncer), read replicas, fail‑over drills.
Raise code quality: enforce ESLint rules, increase Jest coverage > 85 %, mentor two mid‑level devs.

Must‑Have Experience

5+ years building production back‑ends in Node.js/TypeScript.
Deep PostgreSQL performance tuning: EXPLAIN/ANALYSE, index strategy, lock contention, VACUUM/ANALYSE scheduling.
AWS Aurora/RDS operations (scaling, snapshots, parameter groups).
Hands‑on Redis for read caching and rate limiting.
Comfortable bypassing ORMs to craft, test, and ship raw SQL (incl. migrations).
Practical CI/CD knowledge (GitHub Actions, Docker multi‑stage builds).

Nice‑to‑Have

Experience integrating third‑party auth providers (Stytch/Auth0).
Cost‑optimisation mindset in lean start‑ups (right‑sizing RDS, spot instances).
New Relic or Datadog custom dashboards.
Exposure to GraphQL, OpenAPI/Swagger, or event‑driven patterns (SNS/SQS).

If this sounds like something you'd enjoy and be great at, then please apply! This is a remote freelance opportunity, paid via fixed day-rate (negotiable)

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