Senior Node.js Backend Engineer – DeFi Indexers, APIs & Liquidation Bots

Aether Protocol is a collateralized money market. Users supply assets, borrow against them and pay interest; unhealthy positions are liquidated to keep the protocol solvent. AETH is the protocol's incentive token. Our EVM version runs on zkSync, and we are building the Solana version now. You would join a small team of protocol, smart contract and backend engineers. What you'll do You will own the off-chain backend that the protocol, its users and its operators depend on. - Indexing: build services that ingest on-chain events from zkSync and Solana, handle reorgs and missed blocks or slots, and keep a reliable database of markets, positions and interest rates. - APIs: design and run the REST/GraphQL and WebSocket APIs behind our app, analytics and partner integrations. - Keepers and liquidations: build bots that monitor account health, trigger liquidations and refresh on-chain state, with safe transaction submission, retries, nonce/fee handling and key management. - Risk monitoring: track oracle prices, staleness, utilization and borrow caps, and alert the team before problems reach users. - Reliability: own observability, on-call runbooks and incident response for backend services. - Collaboration: work with smart contract and Solana engineers on events, account layouts and admin tooling; review code and raise the team's engineering bar. What we're looking for - 5+ years building production backend services, with at least 3 in Node.js and TypeScript. - Strong experience designing APIs and data models, with PostgreSQL or a similar relational database. - Hands-on blockchain backend work: reading contracts and events with viem, ethers.js or @solana/web3.js, and sending transactions reliably. - Experience with event-driven systems: queues, idempotent processing, retries and backfills. - You run what you build: logging, metrics, alerting, and debugging production incidents. - Good judgement about security: secrets and key handling, input validation, rate limiting. - Clear written communication in English, including design docs and code reviews. Nice to have - Experience with DeFi lending or trading systems: liquidations, health factors, interest-rate models. - Solana backend experience: account subscriptions, priority fees, Geyser or Yellowstone streams. - Oracle integrations such as Chainlink, Pyth or Switchboard. - Running MEV-aware or latency-sensitive bots. - Reading Solidity or Rust well enough to review contract events and account layouts. - Infrastructure as code (Terraform), Kubernetes, and cloud cost management.