Senior Backend Engineer (Node.js / Kotlin)

We're looking for a Senior Backend Engineer to join our backend team and take ownership of building, maintaining, and evolving our microservices. You'll work across both stacks - maintaining existing Node.js services and building new ones in Kotlin - contribute to architecture decisions, and help us maintain high standards of quality and reliability.

About the Project: Our backend is a set of microservices that power the Tangem wallet - providing APIs for wallet synchronization, push notifications, referral and promotional programs, crypto payments, DeFi and staking integrations, and analytics pipelines.

Responsibilities:

• Design, build, and maintain scalable backend services across Node.js and Kotlin stacks;

• Write clean, well-tested code - testing is a first-class concern;

• Own features end-to-end: decompose tasks and make technical decisions;

• Maintain and evolve existing NestJS services while building new services in Kotlin/Spring;

• Occasionally build internal tools and admin interfaces using React;

• Collaborate with product, DevOps, and engineering teams on cross-functional delivery;

• Participate in code reviews, architecture discussions, and continuous improvement of system reliability and observability.

Requirements:

• Strong production experience with Kotlin or Java, and Spring;

• Comfortable working with Node.js and NestJS for maintaining existing services;

• Strong testing practices;

• Deep understanding of software architecture, design patterns, and microservices;

• Experience with AWS services — Lambda, SQS, S3, and others;

• Experience with containerized environments and Kubernetes;

• Good communication and collaboration skills.

Nice to have:

• Experience in fintech, crypto, or payment systems is a plus.

Tech Stack:

• Current services: TypeScript, Node.js, NestJS, TypeORM;

• New services: Kotlin, Spring;

• Infrastructure: AWS, Kubernetes;

• Databases & Storage: PostgreSQL, Redis;

• Messaging: SQS, BullMQ;

• Admin tools: React.

Why Join Us:

• Work alongside a team of skilled engineers on a product used by millions;

• Build with a modern, thoughtfully chosen tech stack;

• Minimal bureaucracy and fast decision-making;

• Real ownership - influence the product, architecture, and business outcomes directly;

• Room to grow technically and shape the platform's future.

What We Offer:

• Stability, development, participation in the future unicorn's growth;

• Remote work from anywhere in the world;

• Competitive salary in EURO/USDT;

• Vacation 20 working days per year;

• Birthday presents;

• Compensation for the purchase of necessary technical devices for the work;

• Paid sick leaves.