Senior Backend Engineer

As a Senior Backend Engineer at SunCrypto, you will own the core systems behind India's next-generation perpetual futures platform. You design, build and operate the backend services that power the order lifecycle, position and margin engine, real-time market data fan-out, liquidity and hedging integrations with global venues, and the ledger that ties it all together. This is a hands-on senior individual-contributor role with real architectural ownership: you write code most days, review others' work, participate in the on-call rotation, and make technical decisions that would otherwise fall to the CTO.

What you'll do

• Design and implement the order lifecycle for perpetual contracts: placement, matching hand-off, partial fills, cancels and amendments with strict sequencing and deterministic replay.
• Build the position, margin and PnL engine: mark price, funding rate application, maintenance margin checks, liquidation triggers and insurance-fund logic.
• Model order books and state in Redis using sorted sets, Streams and Lua-scripted atomic operations, then persist authoritative state in MySQL 8 with correct isolation and locking.
• Implement a double-entry ledger with decimal arithmetic end-to-end, ensuring no floating point anywhere near money.
• Guarantee idempotency and exactly-once semantics across order, fill, funding and transfer events, including crash-recovery and replay.
• Build reconciliation jobs that prove your books balance against external venues, wallets and internal accounts, every hour of every day.
• Scale your WebSocket layer (ws / uWebSockets.js) to tens of thousands of concurrent connections: sharding, heartbeats, reconnect semantics, message batching and per-client backpressure.
• Own REST and WebSocket integrations with Binance, Bybit and OKX futures APIs: signed requests, rate-limit budgets, failover and staleness detection for pricing, liquidity and hedging.
• Run what you build on Linux with Docker, Nginx, PM2, Prometheus and Grafana dashboards, alerting and structured logs that make 3 a.m. incidents debuggable.
• Write load tests and chaos scenarios for the hot path; define SLOs for latency and availability and hold the system to them.
• Raise the engineering bar through design reviews, code reviews, runbooks and mentoring of mid-level engineers.

What you bring

• 4-8 years of professional backend engineering, with at least 2 years on systems where correctness under concurrency was a hard requirement such as payments, trading, ledgers, inventory or booking.
• Expert-level Node.js 20+ in production: you can explain the event loop, libuv thread pool, worker threads and clustering from first principles, and know when each is the wrong tool.
• Strong MySQL 8: you have chosen isolation levels deliberately, debugged a deadlock from the InnoDB status output, and tuned a query plan that mattered.
• Production Redis beyond caching: Lua scripts, Streams or Pub/Sub, and a clear view of AOF / RDB persistence trade-offs.
• Experience building or scaling a real-time WebSocket service and dealing with failure modes: slow consumers, reconnect storms and message ordering.
• Fluency with financial-grade correctness: decimal libraries, idempotency keys, double-entry accounting and exactly-once processing.
• Comfort on Linux with Docker, Nginx, PM2, Git and a monitoring stack; you have been on call and improved the thing that paged you.
• Clear written and verbal communication: design docs, incident write-ups and pull-request descriptions that others can act on.
• Based in, or willing to relocate to, Jaipur.

Nice to have

• Rust or Go: the ability to read and contribute to a Rust/Go matching engine or risk service.
• Prior work at a crypto exchange, broker, prop desk, or a stock-broking / derivatives firm.
• Event pipelines: Kafka, NATS or RabbitMQ for trade, fill and ledger event streams.
• Analytical stores: ClickHouse or TimescaleDB for trade, candle and PnL analytics.
• Infrastructure as code: Kubernetes and Terraform.
• Quant exposure: market making, delta-neutral hedging or options pricing.
• Open-source contributions or public writing on distributed systems, databases or trading infrastructure.

What we offer

• Competitive compensation benchmarked to senior fintech roles.
• Jaipur-based role (on-site / hybrid), full-time.

About SunCrypto

SunCrypto (Angelic Infotech Pvt. Ltd.) is an FIU-IND registered Indian cryptocurrency exchange headquartered in Jaipur, serving Indian retail and institutional customers. It operates under the Prevention of Money Laundering Act and India's VDA tax regime. The company is expanding into derivatives, starting with perpetual futures built in-house by a small, senior engineering team that reports directly to the CTO.