**Senior Backend Developer **
Responsibilities:
- Design and development of .NET services: application business logic, payment and orchestration flows
- Ensuring reliability: idempotency, retries, deduplication, outbox/Saga, failure handling
- Integration of external APIs: correct handling of headers/cookies, formats (multipart/x-www-form-urlencoded, JSON), compliance with specifications
- DB design (PostgreSQL): schemas, indexes, migrations, query and lock optimization
- Performance and scalability optimization: profiling, reducing p95/p99, caching, rate limiting
- Security assurance: secrets storage/KMS, access control, secure configuration and deployment
Requirements:
- 5+ years of experience
- Deep knowledge of network protocols and web integrations: HTTP/2, CORS, cookies, multipart/x-www-form-urlencoded
- Cryptography and formats: Ed25519, SHA-256, working with binary protocols and byte prefixes
- Databases: PostgreSQL, schema design, indexes, transactions, migrations (EF Core)
- Microservices and integrations: gRPC/Protobuf, queues/brokers (RabbitMQ/Kafka), Outbox and idempotency patterns
- Reliability under load: retries, timeouts, polling, rate limiters, circuit breaker
- Observability: Prometheus/Grafana, structured logging, tracing (OpenTelemetry)
- Containerization and CI/CD: Docker, basic deployment and configuration practices
- Clean code and architecture: SOLID, unit and integration tests, code reviews, API design
Will be a plus:
- Experience with anti-bot mechanisms (e.g., Cloudflare: headers, sessions)
- Knowledge of DDD and event-driven approaches, Saga/orchestrators, managing transactional boundaries in distributed systems
- Experience in payment security and anti-fraud, KMS/Secret management
- Experience with property-based testing, load and performance testing, benchmarks
Send your resume to @katyacheresh
