Senior Backend Engineer Bucharest

Senior Backend Engineer
Bucureşti
Bucharest, Bucharest, Romania

Since we were established in 2012, headquartered in the United Kingdom, we have rapidly expanded to lead the way in technology partnerships, collaborating with numerous businesses worldwide.

The Opportunity

A
- 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 Postgre
SQL 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+) / Type
  Script - Express. js - Sequelize ORM

• Aurora Postgre
  SQL 15 primary, Redis/Elasti
  Cache for low‑latency cache

• AWS ECS Fargate - Docker - Git
  Hub 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/pg
  SQL where warranted.

• Evolve schema & data‑model: partitioning/ sharding, BRIN/Gi
  ST indexes, materialised views, retention/archive tables.

• Design & implement caching strategy (Redis key design, TTL, invalidation hooks).

• Protect throughput: connection pooling (Pg
  Bouncer), 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/Type
  Script.

• Deep Postgre
  SQL 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 (Git
  Hub 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 Graph
  QL, Open
  API/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
- rate (negotiable)