[Hiring] Principal Backend / Performance / Database Engineer @iClosed

Role Description

iClosed.io is a SaaS platform for sales and marketing teams, scaling to millions of users. This role sits in our Performance Team and owns the performance and scalability of our Node.js/TypeScript backend services and data layer.

We believe the biggest gains come from design, not just tuning:

• Matching each store to its access pattern
• Moving work off the critical path
• Drawing service boundaries that scale cleanly

This is a senior individual contributor role with no direct reports, high autonomy and significant technical influence.

What you'll do

• Lead the design of high-traffic flows end to end, keeping them fast under load and resilient when dependencies fail.
• Diagnose latency across the full request path using traces, execution plans and metrics.
• Match each workload to the right data store, and document the reasoning.
• Scale reads and writes through caching, replicas, partitioning, sharding and queue-buffered writes.
• Build reliable background processing on SQS and EventBridge with idempotency, retries, dead letters and backpressure.
• Eliminate N+1 queries and chatty data access, including inefficient queries generated by ORMs such as Prisma and Mongoose.
• Own data-layer capacity planning and cost per request alongside latency.
• Set engineering standards: design and query review for hot paths, migration standards, CI regression gates, and load testing at production-realistic volumes.
• Review architecture proposals from feature teams, and write the design docs others build from.

Qualifications

• 5+ years building and operating production backend systems, with 3+ where performance and scale were a named part of your job.
• Performance ownership of a multi-tenant SaaS product under real load.
• Systems you designed yourself, including the alternatives you rejected and the tradeoffs you accepted.
• A concrete track record: a problem you diagnosed, its root cause, your fix, and the before-and-after numbers.
• Strong system design judgement across caching, sharding, CQRS, queues, real-time delivery (WebSockets/SSE), autoscaling, high availability and resilience patterns.
• Real depth in at least two of PostgreSQL/MySQL, MongoDB, DynamoDB and Redis, with working competence in the rest.
• Production ownership of Node.js/TypeScript services, and a solid understanding of how ORMs and ODMs such as Prisma and Mongoose generate queries.
• Hands-on Datadog APM and tracing experience (or equivalent), plus production experience on AWS (ECS/EKS), including the cost behaviour of managed data services.
• Clear writing: design docs a team can build from and an executive can follow.

Data layer depth

• Relational (PostgreSQL, MySQL): execution plans as routine, composite and partial indexes and their write cost, locking, isolation levels, connection pooling and replica lag.
• Document (MongoDB): embedding vs referencing, shard key selection, aggregation performance and working set sizing.
• Key-value: access-pattern-first modelling, partition keys, hot partition avoidance, secondary indexes and capacity cost.
• In-memory cache (Redis/Memcached): caching patterns, key design, eviction and TTL, and system behaviour when the cache is cold or unavailable.
• Across engines: consistency boundaries, dual-write problems, and recognising when a query problem is really an application design problem.

What success looks like

• Diagnosis: latency is attributed to real causes with evidence, and per-tenant investigations end with clear answers.
• Design: critical paths have documented designs others can reason about, store selection is deliberate and written down, and queues behave predictably under load.
• Measurable improvement: meaningful latency reduction on the highest-cost paths, with before-and-after numbers, and cost per request trending down.
• Prevention: design and query review is standard practice for hot paths, regressions are caught before merge, and migration standards are followed across teams.
• Partnership: feature teams bring you proposals early because you make them better, not slower.

Nice to have

• APM, error tracking and database performance tooling using tools like Datadog and Sentry
• Event streaming or messaging at scale
• Real-time delivery and fan-out at scale (Socket.IO)
• Third-party integrations where latency is outside your control
• Noisy-neighbour and tenant isolation
• Load testing tools and building that capability
• SLOs and error budgets
• Infrastructure as code

What this role is not

• Not a DBA role.
• Backups, patching and routine operations sit with DevOps. You set the performance requirements.
• Not feature work.
• Your output is latency removed and regressions prevented.
• Not a management role today.
• Leading the function as it grows is an open conversation.

Why join

• Shape the performance function and its priorities from day one.
• Have direct influence on architecture across every engineering team.
• Work on a polyglot stack at real scale.

Practicalities

• Location: Remote (Pakistan preferred)
• Type: Full-time, permanent
• Level: Senior individual contributor, no direct reports
• Compensation: Market competitive
• On-call: Part of the escalation rota