SENIOR BACKEND DEVELOPER

REMOTE GLOBAL | WEB3

Senior Backend Developer (Remote, full-time)

We are looking for a strong Senior Backend Developer (.NET) who is ready to take on the architecture and development of a high-load payment system. To design complex distributed scenarios, work with TON and external APIs, ensure reliability at the 99.99% level, and influence the product's technical strategy.

What you will be doing: In this role, you will be designing and developing .NET microservices that process thousands of requests per second. Your responsibilities will include payment flows, orchestration, integrations with Fragment/TON, and complex business logic. You will independently make decisions regarding database architecture, search, caching, and fault tolerance.

Key responsibilities: • Ensuring idempotency, retries, and failure handling in a distributed system • Integrating with external APIs with correct handling of headers, cookies, and formats • Designing PostgreSQL schemas and optimizing queries for high loads • Configuring Elasticsearch for fast search and analytics • Reducing p95/p99, profiling, implementing caching and rate limiting • Building observability through Prometheus, Grafana, and OpenTelemetry • Ensuring security at all levels: from secret storage to access control

Tech Stack: .NET (C#) · PostgreSQL · Elasticsearch · gRPC/REST · RabbitMQ/Kafka · Docker · Prometheus/Grafana · OpenTelemetry · cryptography (Ed25519/SHA-256)

What we expect from the candidate: • .NET development experience of 5+ years • Deep knowledge of web integrations: HTTP/2, CORS, cookies, multipart/x-www-form-urlencoded • Experience with cryptography: Ed25519, SHA-256, binary protocols • Strong experience with PostgreSQL (schemas, indexes, transactions, EF Core migrations) • Microservices and brokers: gRPC/Protobuf, RabbitMQ/Kafka, Outbox pattern, idempotency • Elasticsearch: indexes, mappings, DSL, aggregations, DB synchronization • Reliability under load: retries, timeouts, circuit-breaker, rate limiters • Observability: Prometheus/Grafana, structured logging, OpenTelemetry • CI/CD and Docker – practical experience • Clean Architecture, SOLID, unit/integration tests, code reviews

Will be a plus: • Experience with TON (TonSDK, Cell/BOC, ton-proof, Telegram Stars) • Skills in bypassing anti-bot mechanisms (Cloudflare, headers, sessions) • DDD/Event-driven architecture, Saga pattern/orchestrators, distributed transactions • Anti-fraud and payment security, KMS • Skills in writing benchmarks and property-based tests

Work format: remote Time zone: MSK