At Koinly, we’re looking for a Tech Lead (Ruby on Rails) to push our financial data platform to the next level. This role isroughly 80% coding, 20% technical leadership and is ideal for a senior engineer who thrives on solving performance bottlenecks, guiding peers, and shaping architecture without the management overload.
More about us is included at the end of this page.
🔑 Key details
- Report to: Engineering Manager
- Squad: Core
- Team size: 5 senior engineers (within a 10-person backend group)
- Location: Remote, preference for Europe-based candidates
- Salary: USD $100k–120k / year
- Type: Full-time (B2B contractor)
- Experience: 7+ years, prior leadership of senior peers
- Start date: ASAP
- Mission: Lead a small senior team while staying hands-on to solve performance bottlenecks and push technical excellence.
🚀 The challenge ahead
Koinly’s backend reconciles billions of crypto transactions across 900+ integrations. Every millisecond and data point must be accurate. As usage surges, the challenge is keeping our systems fast, reliable, and easy to evolve.
You’ll lead the effort to:
- Keep performance high as scale increases.
- Refactor and simplify complex Ruby systems.
- Mentor senior peers and shape the next generation of our backend architecture.
Clean code and clarity at massive scale, that’s the mission.
🛠️ What you’ll do
Performance and reliability
- Profile, tune, and reduce latency across high-volume ingestion and reconciliation systems.
- Optimize Postgres queries, caching, and background processing.
Architecture and refactoring
- Own and evolve our Ruby + Postgres backend.
- Lead major refactors to improve maintainability and scalability.
- Design data flows and pipelines that reconcile billions of records accurately.
Technical leadership
- Set coding standards, review designs and pull requests, and coach senior engineers through code review.
- Leadership through mentoring, reviews, and technical decision-making (without management overhead).
Collaboration
- Collaborate asynchronously with product, design, and leadership.
- We're light on meetings, heavy on ownership.
- Collaborate through lightweight RFCs and clear written communication
What success looks like?
You’ll make our systems faster, our codebase simpler, and our engineering culture stronger.
🧠 What you bring
- 7+ years’ experience and deep proficiency in Ruby on Rails.
- Proven results improving performance and reliability in production databases (Postgres preferred).
- Strong async communication and mentoring skills.
- Track record of solving performance issues through thoughtful design and clean code.
- Ability to analyze and simplify complex systems.
- Experience with data pipelines, ETL, or reconciliation systems.
Bonus points:
- You have experience working in an async-first, distributed team.
- You've tuned Postgres in production.
- Debugged concurrency issues (deadlocks, race conditions).
- Worked in fintech, taxtech, open banking, or other regulated data domains.
- Familiarity with blockchain or DeFi data structures.
- Understanding of observability practices (metrics, tracing, SLOs).
❎ Don’t meet every checkbox? That’s fine. We care about skill, drive, and how you think.
⚙️ Koinly engineering culture
- Engineering-led values: Maintainability, test coverage, and reliability come before shipping speed
- Craftsmanship mindset: We care deeply about clean, readable code that scales gracefully
- No heroics: Systems are built to be stable, observable, and easy to debug.
- Autonomy & accountability: Small squads, high ownership, minimal bureaucracy.
- Async-first & remote-first: We collaborate primarily through clear writing, not constant meetings
🤝 Ready to take on the challenge?
If scaling complex systems, raising code quality, and leading a senior team while staying hands-on excites you, we’d love to hear from you.
👉 Apply now via the “Apply” button and let’s start the conversation.
Due to regulatory requirements, background checks are part of our process.
