Senior Backend Developer / Tech Lead

Role: Senior Backend Developer / Tech Lead (TypeScript/Node.js). Product: Fintech (crypto wallet, on/off-ramp, crypto cards). Remote | Full-time. What you'll do: Own backend architecture across two large-scale platforms (30+ and 25+ microservices) — system design, API contracts, data flow, inter-service communication. Lead complex integrations with payment providers, card issuers, and blockchain networks — retries, circuit breakers, graceful degradation in production. Drive performance: profile slow services, design caching strategies, optimize queries, plan for scale. Shape technical direction and make architectural decisions. Build and extend AI-powered internal tools and automations — our team runs LLM-based systems across the full dev cycle, and you'll take it further. What you bring: 5+ years TypeScript/Node.js in production. NestJS for 2+ years — modules, guards, interceptors, microservice transports. Deep PostgreSQL: schema design, indexing, EXPLAIN ANALYZE, zero-downtime migrations, database-per-service pattern. Real microservices experience — RPC + pub/sub, message brokers, idempotency, eventual consistency, saga/outbox. Production blockchain (MUST-HAVE) — HD wallets (BIP32/BIP39), smart contracts, ABI, multichain, on-chain transactions with real user funds. ethers.js / viem / @solana/web3.js. AI-driven workflow (MUST-HAVE) — you use Claude, Copilot, or Cursor daily. You've built automations or LLM-powered tools, not just prompted ChatGPT for code snippets. System design skills — you can whiteboard a distributed system and defend every decision to engineers and stakeholders alike. English Upper-Intermediate. Russian — fluent. Nice to have: NATS JetStream (streams, consumers, delivery policies), observability stack (OpenTelemetry, Prometheus + Grafana, pino, distributed tracing), Kubernetes with Helm/Kustomize, fintech domain (PCI DSS, KYC/AML, payment systems), experience mentoring mid-level engineers, React basics for back-office UIs. What we offer: Fully remote — international team, async-friendly culture. Two career tracks: grow into Tech Lead or go deep as Staff/Principal IC. Real architectural ownership — not ticket execution. An engineering culture built around AI tools at every stage: analysis, implementation, code review. Competitive salary, transparent feedback, low bureaucracy.