Senior Backend Engineer
Location: Onsite (Lahore)
Experience: 3–6+ Years
Employment Type: Full-time
Stack: Node.js, NestJS, PostgreSQL, Redis, AWS
Job Overview
We are hiring a Senior Backend Engineer to design, build, and scale core backend systems for a mobile gaming platform. You will work on high-impact systems including wallet, rewards, transactions, fraud detection, payouts, and admin modules. The role requires strong ownership of backend systems from design to production, ensuring scalability, performance, and correctness at scale.
Responsibilities
- Design, develop, and maintain scalable backend systems using Node.js and NestJS with a strong focus on clean architecture and maintainability
- Build and manage wallet, reward, and transaction systems ensuring accurate balance handling and consistent user state
- Develop ledger-based financial systems ensuring every transaction is recorded, traceable, and concurrency-safe
- Implement payout workflows including debit processing, external payout handling, reconciliation, and failure recovery
- Design and implement fraud detection systems using behavioral rules, velocity checks, and device-based signals
- Ensure data consistency and correctness in high-concurrency environments with proper handling of race conditions
- Optimize PostgreSQL queries, indexing, schema design, and database performance under heavy load
- Implement Redis-based caching, idempotency mechanisms, and performance optimization strategies
- Work with message queues for background processing, retries, and reliable asynchronous workflows
- Participate in system design and contribute to improving modular backend architecture for scalability
- Monitor production systems, debug live issues, and ensure system reliability using AWS and logging tools
- Own production features post-deployment, including incident response and root-cause analysis
- Collaborate with mobile and product teams to define and integrate API contracts
- Write clean, testable code with proper unit and integration testing practices
- Follow strong engineering discipline including code reviews, small PRs, and proper documentation
Required Skills
- 5+ years of backend development experience
- Strong expertise in Node.js and TypeScript (strict mode)
- Experience with NestJS or similar backend frameworks
- Strong knowledge of PostgreSQL (transactions, indexing, migrations, query optimization)
- Strong experience with Redis (caching, idempotency, performance optimization)
- Experience with message queues (Bull, BullMQ, SQS, Kafka, etc.)
- Understanding of distributed systems (retries, backoff, at-least-once delivery)
- Hands-on experience with AWS (ECS, RDS, ElastiCache, ALB, Secrets Manager)
- Strong understanding of concurrency, race conditions, and data consistency
- Experience with financial systems, wallets, ledgers, or transaction-heavy applications
- Strong Git workflow and code review practices
- Experience with unit and integration testing (Jest or similar)
Nice to Have
- Experience in fraud detection or anti-abuse systems at scale
- Experience with ad networks (AdMob, AppLovin, ironSource)
- Mobile attestation systems (Play Integrity, DeviceCheck)
- Experience with payout providers (PayPal, Amazon Incentives, etc.)
- Observability tools (Prometheus, Grafana, OpenTelemetry, structured logging)
