Senior/Staff Backend Engineer, Identity Platform

Phantom; Poland; Remote; PLN 180,000 - 240,000; Full time

Job summary

A leading blockchain company in Poland is seeking an experienced backend engineer to lead the design and implementation of core authentication infrastructure. You will enhance security measures and manage user identity protocols. The ideal candidate has over 7 years of experience and a strong knowledge of backend systems. This role offers a competitive salary, flexible hours, and unlimited vacation.

Benefits

Competitive salary and equity

Comprehensive insurance

Flexible hours

Unlimited vacation

401(k) retirement plan

Qualifications

• 7+ years of backend experience with high-availability systems.
• Deep expertise in authentication protocols and key management services.
• Strong system design skills with a focus on performance.

Responsibilities

• Lead the design and implementation of authentication systems.
• Build and maintain secure secrets management solutions.
• Define and maintain stable authentication APIs.

Skills

Backend Experience

Authentication Protocols

Web3/Crypto Knowledge

System Design & Architecture

Leadership & Communication

Tools

Node.js

TypeScript

Rust

NestJS

Job description

Role Description

You will own and evolve the core authentication infrastructure that secures every Phantom account. Reporting to the Engineering Manager, you’ll lead the design, implementation, and operation of our hardened Auth stack, multi-factor authentication methods, and next-gen key-management services. Your work will directly reduce account-takeover risk and empower every product team with rock-solid identity foundations.

Responsibilities

• Authentication systems

  • Architect and ship production-grade improvements to Phantom’s Auth stack (e.g. secure enclaves, hardened token flows, threat modeling).

  • Passkey (WebAuthn) & MFA

• Secrets management

  • Design and build systems using modern secrets management technologies to push security and functionality to the next level

• APIs & Integration

  • Define and maintain stable, versioned auth APIs for downstream teams

  • Partner with cross-functional stakeholders to ensure seamless rollouts

Qualifications

• 7+ Years of Backend Experience: Demonstrated success in building large-scale, high-availability systems in Node.js, TypeScript, Rust, NestJS (or similar frameworks).

• Deep expertise in authentication protocols (OAuth2/OIDC, WebAuthn/Passkeys, OTP), Strong background in key management services (e.g. AWS KMS, Vault) and cryptography

• Web3/Crypto Knowledge: Familiarity with on-chain data, wallet integrations, or decentralized application patterns is strongly preferred.

• Strong System Design & Architecture Skills: Ability to translate product requirements into scalable, maintainable solutions, with a keen eye for performance trade-offs and fault tolerance.

• Leadership & Communication: Experience mentoring engineers, leading technical initiatives, and collaborating effectively with cross-functional teams.

Why Work with Us

We are a team of experienced builders in the blockchain and crypto industry. Our journey began from users seeking an easy, seamless path to accessing the crypto ecosystem. This passion fueled our exponential growth, allowing us to onboard over 16M+ active users in just over three years; with our user base growing weekly. Our dedication to a secure and seamless user experience has made us the leading wallet on Solana as well as our multi-chain approach enhances our platform\'s versatility, meeting the needs of a diverse and growing user base. By staying at the forefront of technology and user expectations, we continue to innovate and set industry standards on self-custodial crypto wallets.

There has never been a better time to work in crypto to help shape the future of innovation with a focus around the wallet experience!

• First impressions matter: Wallets are responsible for a users first impression with crypto and onboarding new users into crypto. By ensuring that a user has a great first-time experience with crypto, we can help supercharge the growth of the entire ecosystem.

• Make crypto easier to navigate: There is no easy way for a user to discover and navigate all that crypto has to offer. Wallets have a unique opportunity to help users not only onboard to crypto but also stay retained by exploring new things to do.

• We live in a multi-chain world: We currently support Solana, Ethereum, Polygon and Bitcoin with more networks to come in the new future. We are focused on creating a unified, multi-chain crypto experience for users.

Benefits

• Competitive salary and equity

• Comprehensive insurance (medical/dental/vision) — 100% covered

• Stipend for your ideal remote set-up

• Flexible hours and a supportive remote environment

• Unlimited vacation: Take time when you need it (and we really mean it!)

• 401(k) retirement plan

• Monthly wellness benefit

• Weekly meal benefit

• Global off-sites

We strongly encourage candidates of all different backgrounds to apply. We believe that our work is stronger with a variety of perspectives, and we’re eager to further diversify our company. If you have a background that you feel would make an impact at Phantom, please consider applying. We’re committed to building an inclusive, supportive place for you to do the best work of your career.

By submitting your resume and application materials, you acknowledge and agree that Phantom may use automated tools, including AI systems, and may engage trusted third-party service providers to process your application and ensure an efficient hiring process. Phantom does not sell your information and your materials will be handled securely and in accordance with applicable data protection laws.