Expert JavaScript Engineer (Web3)

TL;DR

Expert JavaScript Engineer (Fullstack/Web3): Designing and implementing rich frontend experiences and scalable backend services for wallet infrastructure with an accent on security, reliability, and scalability. Focus on building secure-by-default systems and developer tooling for the next generation of financial applications.

Location: Remote (Bulgaria)

Company

A custom product engineering company that supports multinational organizations and scaling startups in solving complex business challenges.

What you will do

• Design and implement frontend experiences and scalable backend services for wallet infrastructure.
• Own features across the stack from technical design and architecture through deployment and optimization.
• Build backend services and APIs supporting authentication, wallets, and payments infrastructure.
• Develop user-facing features and frontend tooling for both end-users and developers.
• Collaborate with Product, Design, and other engineering teams to deliver high-impact features.
• Contribute to performance, reliability, and scalability improvements across the platform.

Requirements

• 3–5 years of experience building and shipping production-grade full-stack web applications.
• Experience building backend systems and APIs using Node.js and frameworks such as Express.
• Must be based in Bulgaria.
• Comfort working across frontend and backend systems in complex, evolving codebases.
• Strong appreciation for clean, maintainable code and system performance.

Nice to have

• Experience with blockchain technologies (EVM chains, wallets, on-chain integrations).
• Solidity experience including writing, deploying, and testing smart contracts.
• Experience with various state management solutions in production React applications.
• Experience with security products or other high-sensitivity domains.

Culture & Benefits

• Regular performance-based salary reviews.
• Tailored education paths including full access to Udemy and certifications.
• 25 paid days off (20 vacation days + 5 undocumented sick leave days).
• Additional health insurance and 100% company-covered Multisport card.
• Internal Mobility Program and regular corporate events, webinars, and meetups.