**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 *******×**.
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
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)