Middle+ Back-End Developer (Slots)

Middle+ Back-End Developer (Slots)

Employment: Full-time

Salary: $2,800–3,500 net (depending on interview results and experience)

Probation Period: 1 month

Tech Stack

Node.js · TypeScript · Fastify · PostgreSQL · WebSocket/Socket.IO · Firebase Auth · Provably Fair (HMAC-SHA256) · BigInt · Docker

Responsibilities

Design and develop the game engine using Node.js, TypeScript, and Fastify, including round state machines, outcome taxonomy, autoplay, and bet cancellation.

Implement Provably Fair mechanics (HMAC-SHA256) with server-side generation and verification, as well as precise financial calculations using BigInt.

Develop and maintain the wallet and transaction system, including multi-currency support, deposits, withdrawals, idempotency, and balance consistency.

Build platform features such as KYC, VIP levels, affiliate programs, leaderboards, and notifications.

Integrate external betting APIs, implement real-time communication using WebSocket/Socket.IO, and maintain authentication via Firebase.

Design and optimize PostgreSQL databases, work with Docker/Docker Compose, and ensure critical business logic is covered by automated tests.

Participate in code reviews and contribute to maintaining high standards of code quality, performance, and security.

Requirements

3+ years of back-end development experience with Node.js and TypeScript.

Strong knowledge of Fastify or Express.

Experience designing transactional systems, including balances, payment processing, idempotency, and PostgreSQL.

Solid understanding of deterministic computations, state machines, and precise financial calculations using BigInt or decimal-based arithmetic.

Experience integrating third-party APIs and building real-time applications.

Ability to work independently, write tests, conduct code reviews, and follow secure development practices.

Experience in iGaming/casino development, including Provably Fair algorithms (HMAC-SHA256) and RNG mechanics.

Nice to Have

Experience with Firebase Authentication (including 2FA/TOTP).

Experience implementing KYC/AML processes.

Experience with VIP and affiliate systems.

Familiarity with regulated betting platforms.

Experience building high-load financial or transactional systems.

What We Offer

Full-time employment.

Competitive salary of $2,800–3,500 net, based on experience and interview results.

1-month probation period.