Typescript / React / Node / PostgreSQL / WebSockets

Location: On-site in Copenhagen, Denmark (no full-remote option)

Level: Senior

Company: Francis

We’re building Francis: a collaborative spreadsheet for financial modeling that does the heavy lifting Excel users wish they didn’t have to. It’s fast, multiplayer, deeply expressive — and powered by a custom-built formula language under the hood.

This is not just another CRUD app. We’re building a product where performance, ergonomics, and product design all converge — in the browser, in real time, with no room for bloat.

We’re a small team of four, including two engineers. We’re looking to bring on a third engineer to help push the limits of what a browser-based spreadsheet can be.

We work in-person at our office in Copenhagen. We pair frequently, think out loud, and make technical and product decisions collaboratively. You’ll have a strong influence on everything we build.

We’re a very small team trying to be fast, deliver quality and have no bureaucracy. Despite our team size, we’re already serving hundreds of companies.

About the job

We’re looking for a full stack engineer who’s excited to:

• Dive deep into real user workflows to understand their mental models and pain points.

• Turn ambiguous product ideas into elegant, maintainable full-stack implementations.

• Push the limits of what can be done in the browser — squeezing every bit of performance from React and the DOM.

• Design APIs and backend systems that support fast, real-time collaboration.

• Shape the engineering culture, architecture, and product direction as an early team member.

• Solve difficult puzzles.

What you’ll do

• Help bring the most promising concepts into the hands of our users.

• Design and implement full-stack features across our entire codebase.

• Shape core infrastructure for our collaborative engine (WebSockets, conflict resolution, real-time sync).

• Contribute to the design of our formula language — the embedded language that powers the spreadsheet (tokenizer, parser, interpreter).

• Work closely with the team to deeply understand user workflows, and find elegant, product-driven technical solutions.

• Tackle performance challenges in the browser, like virtualized rendering, optimizing React re-renders, multi-layer caching and algorithmic time-complexity.

• Build AI-based features that actually improve the product.

• Build test infrastructure and property-based tests to ensure correctness in edge cases.

To give you an idea about the type of work you’ll encounter, here are some examples of work we have done recently.

• Prototyped a visual tree-based editor based on react-flow for end-user managed configuration of spreadsheets with templating/inheritance.

• Real-time collaboration over websockets, with automatic conflict resolution for edits in the spreadsheet.

• Commenting feature for collaboration with e-mail notifications sent to mentioned parties.

• Aggressive performance optimization of the cache invalidation in our calculation engine aided by browser performance profiling.

We’re co-located in our Copenhagen office. We believe working in the same space and on the same schedule boosts productivity, learning and fun.

Why this role is exciting

• You’ll be shaping a technically ambitious product used by real customers every day.

• You’ll work on performance-critical systems, real-time collaboration, and language design — all in the browser.

• You’ll be part of a tiny, high-trust team where your work has massive impact.

• You’ll be challenged and (almost surely) learn a lot.

Our stack

• TypeScript (across frontend and backend)

• React + Redux + Tailwind CSS

• Node.js + Express

• PostgreSQL + Redis

• WebSockets for real-time collaboration

• Custom formula language designed and implemented in-house

About you

• Have solid experience building performant applications + UIs using React and Tailwind.

• Love thinking in systems — performance, abstractions, tradeoffs.

• Enjoy pair programming, deep technical discussions, and co-owning product decisions.

• Are intrigued by the idea of building something that looks simple, but is technically ambitious under the hood.

• Have a solid grasp of computer science fundamentals — data structures, algorithms, and performance tradeoffs.

• Likely 5+ years of industry experience (or exceptionally motivated)

About us

The journey

We prioritize healthy growth

• We have 300+ companies using our platform

• We haven’t scaled prematurely, but taken time to get it right

• We're profitable

What we offer

• Interesting and challenging work

• Competitive salary + equity

• Office with great colleagues

• Flexible working hours

• 5 weeks of paid vacation

• Paid lunch

• Private health insurance

• Pension plan

• Parental leave

If you’re curious, capable, and up for a challenge, we’d love to hear from you.

The interview process

• Intro meeting: A short conversation to discuss vision, role expectations, and cultural fit.

• Meeting with two co-founders: A longer discussion with leadership on strategy, design philosophy, and collaboration.

• Meeting with the team: Conversation with the entire team to assess working dynamics and alignment.

• Final decision: A decision is made and communicated.