Staff Software Engineer

✨ Featured
Remote - EU Remote - Europe Remote - UK Contract Staff
US$ 100K - US$ 115K Yearly

Published on November 07, 2025

At Koinly, we are building software to help crypto investors stay compliant with their tax obligations and keep track of their investments. We launched the first version of our platform in 2019 and have since grown to over 1.5M users by solving a highly technical problem and saving our users countless hours of work. All of this with a small team of super intelligent and dedicated individuals!

At Koinly, we’re on a mission to simplify crypto taxes and asset tracking. Our platform helps investors stay compliant, track assets across hundreds of wallets, exchanges, and DeFi platforms and save hours of time. Most users finish their crypto taxes in 20 minutes instead of days or weeks, giving them the confidence to grow their portfolios long term.

Behind that simplicity lies a deeply technical product: large-scale data processing, billions of rows, and integrations with 1000+ platforms. Our stack is pure Ruby and Ruby on Rails, with high test coverage and uncompromising standards on code quality and system performance.

More about us
  • We are one of the fastest-growing crypto tax calculators in the world with solid product–market fit.
  • Trusted and loved: don’t take our word for it, see what our customers say 
  • Used by hundreds of thousands of investors and accountants, and a partner to major crypto exchanges.

Our culture is async, engineering-driven, and free from unnecessary processes. We pride ourselves on having very high test coverage and rarely having any prod issues. We’re a fully remote-first, successful startup with product-market fit in a niche (and booming) domain: crypto taxes. If you value autonomy, technical excellence, and clear communication over meetings and process complexity, Koinly is the place for you.

💎 About the role

As a Staff IC you will simplify complex Ruby systems, increase throughput, and shape the architecture behind fast, precise financial data.

Quick facts
  • Location: Remote, Europe TZ overlap preferred
  • Role-Type: Full-Time
  • Employment type: B2B
  • Reports To: Engineering Manager
  • Compensation: $100,000 to $115,000 per year 
  • Perks:
    • 32 days of PTO.
    • Async culture.
    • Flexible work-schedule.
    • A culture of high autonomy and ownership.
  • Experience level: 7+ years.
  • Start date: ASAP.
  • Team size: 10 person engineering team.
  • Main responsibility: Engineer and optimize high-performance Ruby systems that handle billions of financial transactions, solving deep scaling, data, and code-quality challenges.

What you'll do
  • Design and develop scalable backend systems that process billions of financial transactions.
  • Provide technical direction across projects and collaborate with product and engineering leads to define priorities and architecture.
  • Own project delivery: from design and implementation to performance and reliability in production.
  • Refactor and modernize core Ruby systems to improve maintainability, readability, and speed.
  • Mentor other engineers through technical reviews, design discussions, and clear documentation.

💼 What you bring:

  • 7+ years of backend experience with Ruby on Rails at scale, with at least 2 years as a senior engineer, influencing cross-team initiatives.
  • Proven record improving system performance and code quality.
  • Strong understanding of data flows and software design principles.
  • Experience working cross-functionally in async, remote environments.
  • Clear communication and ownership mindset.

Bonus:
  • Experience tuning Postgres in production.
  • Built or optimized data ingestion or reconciliation pipelines.
  • Open-source contributions to Ruby, Rails, or performance tooling.
  • Background in fintech, taxtech, open banking, or blockchain systems.


👥 Koinly's engineering culture

⚙️ Craftsmanship matters: we value deep thinking, well-structured systems, and clean code.
💬 Async-first collaboration: clarity and autonomy come through written communication.
🚀 Impact through ownership: engineers drive projects end to end.
🌍 Remote: we trust people to work flexibly and deliver excellence from anywhere.


How to apply

Here’s what you can expect from the rest of our hiring process:
  1. A phone screen with our People Operations team
  2. Take-home assignment
  3. A technical interview based on your assignment

We’ll keep you informed through every step. To get started, click on "apply for this job" and you'll be redirected to the main job ad. Go through the application form on that page and you're set! We read every single application, and your resume and responses help put your experience into context.
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