Backend Developer (TypeScript/Node.js)

AYA Group is hiring a Middle Backend Developer (TypeScript/Node.js) with 3-6 years of experience, full-time, remote. Develop services for cards, accounts, operations, subscriptions, referral system and commissions.

Develop services for cards, accounts, operations, subscriptions, referral system and commissions — from data schema to API and background handlers. Work with monetary logic in PostgreSQL: understand functions and triggers, maintain balance invariants, design transactions, locks, indexes and safe migrations. Develop Kafka and Pub/Sub handlers: ensure idempotency, deduplication, correct retries and recovery after partial failures. Maintain common Kafka controller and application event streams. Develop GraphQL and REST APIs, as well as WebSocket events. Maintain backward compatibility with independently released client applications. Integrate with card, KYC, crypto and email providers, handle webhooks and correctly handle cases when the result of an external call is unknown. Manage the subsystem end-to-end: clarify business rules, design a solution, release it, verify the result and document important scenarios. Plan schema and data changes without stopping critical production scenarios. Investigate application-level incidents along the API → DB → queue → provider chain and safely restore incomplete operations. Participate in code review and technical decisions; together with QA improve checks, agree contracts with frontend and mobile.

At least 4 years of commercial backend development in TypeScript/Node.js. Experience with Bun is useful, but not required. Strong PostgreSQL: manual SQL, query plans, indexes, transactions, locks and isolation levels; ability to understand a large existing schema. Experience with PL/pgSQL, triggers and stored functions, or willingness to quickly master this layer. The database here not only stores data: part of the monetary rules are implemented in it. Understanding of systems with monetary state: postings and double entry, holds, operation statuses, multicurrency, conversions, rounding precision, reconciliation and compensation. Experience with Kafka, Pub/Sub or RabbitMQ: at-least-once delivery, reprocessing, deduplication, and understanding of boundaries between queue, DB and external service. Experience with GraphQL and/or REST. Schema-first approach and type codegen will be a plus. Ability to safely change a live system: maintain backward compatibility, plan migration and deployment order, limit rollout and verify result after release. Autonomy: ability to take a task in business terms, clarify missing rules, design a solution and bring it to production. Engineering neatness: strict typing, static analysis, tests in the most risky places, clear verification scenarios and up-to-date documentation. Ability to investigate failures by specific identifiers and data, separate facts from hypotheses, and not repeat a monetary or external operation without verifying the result. Nice to have: ClickHouse, GCP Cloud Run, Pub/Sub and Cloud Functions, Docker, GitLab CI, Redis, WebSocket, Sentry, experience in fintech or crypto products.

Full-time employment. Schedule 5/2. Remote work.