Frontend Staff Engineer

Koinly is a successful product used by crypto investors around the world, helping them make sense of complex portfolios and tax obligations across chains, wallets, exchanges, and Defi protocols. The bar is simple to describe and hard to deliver: a user should be able to reconcile thousands of transactions and file their taxes in under 20 minutes.

We're looking for a Frontend Staff Engineer to take deep ownership of our data platform - the engine behind products at the intersection of crypto, finance, and tax. You'll work across a modern React web application and a high-performance distributed data-processing backend, with a new React Native mobile app joining your scope in the future.

This is a senior, hands-on role for someone who combines exceptional architecture/engineering craft with complete ownership of the visual and UI layer. In our engineering-driven environment, we do not rely on dedicated UI designers. You are expected to lead by example: writing high-quality code, making sound architectural decisions, and taking personal pride in building intuitive, highly polished UI components that users interact with daily.

We’re a remote-first, async-first startup with deep product-market fit. If you value autonomy, technical excellence, and clear communication over meetings and process complexity, Koinly is the place for you.

Read on for responsibilities, requirements, and who we are. 👇

Role at a glance

• Mission: Own frontend features end-to-end ensuring a high-performance experience for complex crypto tax data.

• Location: Remote - Strictly Europe (EU / UK timezones)

  • Note, we won’t review job applications from outside Europe.

• Employment: B2B Contract.

• Compensation: USD $80k – $120k/y.

• Perks: 32 days PTO (incl. public holidays).

• Experience: 8+ years with a focus on complex, data-heavy web applications.

🚀 Work within one of the most rapidly growing industries in the world

What we're looking for

We're looking for someone who thrives on complex, business-critical financial web applications - systems with real architectural depth and high stakes. You’ll focus on optimizing, refactoring, and elevating our existing codebase while steadily delivering critical new features for a high-performance interface that handles massive datasets and complex DeFi reconciliations.

Above all, we value a high sense of product ownership, exceptional code quality, autonomy, and openness: you take responsibility for outcomes, not just tasks, and you work independently while staying transparent and collaborative.

We also expect:

• Deep understanding of modern, complex web application architecture and the design patterns that support it at scale.

• Work closely with product, serving as the primary frontend partner for Product. You’ll evaluate ideas from a technical perspective, propose creative solutions, and take real ownership of our frontend strategy.

• Visual & interface responsibility, because we don't pass off designs from a dedicated UI team, you naturally care about visual hierarchy, layout consistency, micro-interactions, and component design.

• Strong attention to detail and advanced frontend styling skills, including reliable cross-browser behavior and pixel-level precision.

• Fluency with the latest AI development tools such as Claude/Codex/Cursor, and the judgment to use them effectively in a professional workflow.

Tech stack

You should have deep, production-level experience across our core stack:

Frontend

• React 19 with the React Compiler, in strict, modern TypeScript

• TanStack ecosystem - Router, Query, and Table

• Radix UI and Mantine for components

• Tailwind CSS v4 (with class-variance-authority and tailwind-merge)

• Vite + Vitest (unit and browser/Playwright), Storybook with Chromatic for visual regression

• Highcharts for data visualization and Sentry for error monitoring

• Bun runtime with modern TS tooling (oxlint, Biome)

• Data parsing and wrangling: csv-parse, xlsx (SheetJS), node-html-parser

• Blockchain libraries

• RabbitMQ, and Redis (ioredis)

Infrastructure & tooling

• PostgreSQL, Heroku, GitHub, JIRA

Nice to have

• Experience building mobile applications with React Native (we plan to expand into mobile).

• Public portfolio of projects available on GitHub or similar platforms.

• Background working on financial products.

• Hands-on experience with blockchain and crypto technologies.

• Familiarity with Ruby (our services interoperate with a Ruby codebase).

• Understanding of DeFi protocols and how they work on-chain.

• Knows and understands our product.

✔️ Don’t tick all of the boxes? Neither do we 🤷

We're driven by hiring not only by experience and relevance but also by ambition. We celebrate anything ‘outside of the box’, so if you don’t meet every single listed criterion, please do still apply—we’d love to hear from you.

That said, there are two hard gates for this role:

1. Expert-level TypeScript. You should reach for strong typing instinctively, not as an afterthought. We deal with complex financial data where "mostly correct" isn't good enough; your TS skills should reflect that.

2. Deep React experience. This is a Staff level role. You should have a deep understanding of React’s internals, performance optimization, and modern tooling. We need someone who can hit the ground running with a complex, established codebase.

Why join Koinly as a frontend engineer?

• One of the fastest-growing Crypto Tax Calculators in the world with solid product-market fit.

• Trusted and loved: See what our customers say on Trustpilot.

• Direct impact: Our users rely on Koinly for their financial compliance. Every performance optimization and UX improvement you ship directly reduces the stress of hundreds of thousands of investors.

• True ownership: We don't believe in "ticket-flipping." You'll own features from the initial requirement through to the final interaction. You have the autonomy to make architectural decisions that stick.

• High-signal, low-noise: We're remote-first and async-first. We don't do unnecessary meetings or processes for the sake of process. You’ll have long blocks of deep work time to actually build.

🚀 Come and shape the future of crypto tax with us

We aren't just building a calculator; we're building a platform that empowers crypto investors to make the best decisions for their financial future. If you’re ready to own a piece of that journey and build a product people actually need, we want to hear from you.

Compliance and privacy

Due to our domain, background checks are required before joining. By applying, you consent to processing your data for recruitment purposes per our privacy policy.