Senior Backend Engineer

We're looking for a Senior Backend Engineer to join our backend team at Zerion. This team builds and evolves the backend systems at the core of our products and customer-facing solutions. In this role, you'll design and operate distributed systems, work with Web3 infrastructure, and collaborate closely with product, support, and the clients building on our API to deliver reliable, scalable solutions. We value strong ownership, thoughtful system design, and a high bar for code quality. If you enjoy building solid systems, moving fast without cutting corners, and using AI as a core part of how you work, you'll feel right at home with us.

What You’ll Do

• Design, build, and maintain  scalable distributed backend systems powering platform and product capabilities.

• Own backend services end-to-end : from architecture and implementation to monitoring and long-term reliability.

• Work closely with  product and engineering peers to actively shape product decisions — not just execute specs.

• Scope solutions with the clients building on our API: turn a vague request into a concrete proposal, and the proposal into a plan the team can build.

• Build and evolve  Web3 platform backend components , including protocol integrations, support for newly emerging blockchain networks, and reliable interactions with smart contracts.

• Ensure  high standards of code quality , performance, security, and observability.

• Operate comfortably in a  fast-paced startup environment , balancing speed and correctness.

• Use AI as a core part of your engineering workflow — designing, reviewing, debugging and shipping with it. This is how the team works day to day, not an experiment we're running.

• Contribute to technical discussions , reviews, and mentorship within the engineering team.

What We’re Looking For

• 5+ years of experience designing and building distributed backend systems .

• Strong knowledge of algorithms, data structures, and software design patterns .

• Comfortable working in a fast-paced startup environment .

• Strong desire to actively contribute to product evolution , not just implementation.

• Comfortable working directly with customers — hearing a vague problem and coming back with a concrete proposal.

• Hands-on, daily use of AI in your engineering work . You should be able to talk concretely about where it has changed how you build, and where you've learned not to trust it.

• High standards for code quality, system reliability, and user experience — you care about getting it right, not just getting it done.

• Strong ownership mindset — you take responsibility for outcomes, not just tasks.

• Clear and proactive communication in a distributed team.

• Pragmatic decision-making: knowing when to move fast vs. go deep .

• Ability to learn quickly and adapt .

Technical Skill Set

• Excellent knowledge of Golang is a plus, not a blocker.

• Experience with containerized systems : Docker & Kubernetes.

• Experience with databases :

  • SQL: Postgres

  • NoSQL: MongoDB, Cassandra

• Experience with monitoring and observability tools : Sentry, Prometheus, Grafana.

• Hands-on experience with AWS (Amazon Web Services) .

• Experience with Python 3 .

• Comfort experimenting with and integrating AI-assisted workflows into daily engineering work.

Bonus Points

• Hands-on Web3 experience: Blockchain systems, dApps, Smart contracts.

• Prior experience in a startup environment that emphasizes trust and autonomy .

• Located in time zones close to Europe for smoother collaboration.

• Collaborative mindset and respect for different perspectives.

• Curiosity and willingness to challenge existing solutions when better ones exist.

Interview Process

• Screening Call – 30 minutes

• Hiring Manager Interview – 45 minutes

• Technical Interview – 90 minutes (includes a real-world challenge where you'll work with AI tools directly)

• System Design Interview – 90 minutes

• Team Interview – 60 minutes

• Founders Call – up to 60 minutes

• Reference Check

Why You Should Join

Company Overview

Zerion API

Trusted by 50+ top crypto and fintech brands

Powering 2k+ active clients monthly

Over 10B total requests processed

A lean, senior AI-native team shipping at outsized scale

Zerion Wallet

1.7M + active funded wallets

27.6M + transactions

2.5B + transaction volume

416K+ unique holders of Zerion DNA NFT

Culture : Our culture shines through in our strong team engagement and impressive retention, showing just how much we value creating a workplace where people truly want to stay and thrive.

People : Collaborate with some of the most driven and intelligent individuals in the crypto space.

Salary & Benefits: Receive a competitive salary, medical insurance, coworking membership, and additional benefits.

Unlimited Days Off and Flexible Work Schedule : Recharge and explore life outside the office with our flexible time-off policy and work schedule.

Remote Work Essentials : We provide all the necessary software and equipment to ensure you're fully equipped to work from home comfortably and efficiently.

Stock Option s: Contribute to Zerion's success and watch your stock options become valuable.

Travel: Connect with your teammates around the world at industry events and our annual team offsite.

Distributed Team: Zerion is a fully remote team with members worldwide. Embrace asynchronous collaboration, find your own work rhythm, and enjoy a healthy work-life balance.

To ALL recruitment agencies and individual recruiters : Zerion only accepts resumes from its partners, with whom Zerion has contractual relations. Zerion is not responsible for any fees or charges associated with unsolicited resumes.

We read every application in full before moving forward - as part of that, please include the word WATERMELON somewhere in your answer to the application question below