Lead Full-Stack Engineer (Mobile-first) — FinTech

Finland / Sweden only | Remote-first | Team in Vaasa, Finland | Lead from day 1

The main thing

We’re hiring a Lead Engineer with real ownership: set direction, ship product, and keep production stable.

The product is already live (soft-launched in Q4 2025 on the App Store and Google Play in Finland and Sweden). Next, we’ll strengthen the core experience, ship key integrations, and later launch  to support expansion into additional EU markets.

You’ll lead by building: making pragmatic technical decisions, raising the quality bar, and helping us scale the engineering function over time.

About Rensa

Rensa Ab Oy is building next-generation personal finance for European markets. The next phase is execution: stabilizing production, improving core flows, and building integrations that unlock the product’s next steps.

What you’ll do

• Build and lead the engineering function (hands-on)
• Own the product end-to-end: mobile app → backend → cloud → releases
• Make pragmatic technical decisions and keep delivery moving (lean team, fast iteration)
• Improve stability: monitoring, error handling, performance, and clean releases
• Build and maintain integrations (banking, payments, auth providers, messaging, etc.)
• Work closely with management on what to build next and how

Stack

• Mobile: Expo / React Native / TypeScript
• Backend: .NET 8 ( Core), SQL Server
• Cloud: Azure
• Auth: JWT, Google/Apple OAuth, biometrics
• Integrations: banking + payments (current providers), RevenueCat
• Observability/analytics: PostHog/Sentry (and/or Firebase depending on pipeline)

You don’t need to love every tool above — but you should be comfortable owning a real production app.

What we’re looking for

Must-have

• At least 5 years of experience in software development
• Fluent in Finnish or Swedish
• You’ve shipped and operated real production software (mobile and/or full-stack)
• Comfortable using AI coding tools (e.g., Claude Code, GitHub Copilot, Codex CLI, Cursor) to speed up development
• You can lead execution: decide, implement, unblock, deliver
• Solid API + integration skills (working with external services, auth flows, REST/JSON)
• Comfort with production ownership (deployments, incidents, debugging)

Nice-to-have

• Experience leading a software development team
• Experience with mobile measurement / attribution tooling (e.g., Firebase, Adjust, AppsFlyer, Branch)
• Fintech / payments / banking integrations
• Strong UX instincts (mobile polish, clarity, reducing friction)

Work model

Remote-first within Finland or Sweden. The team is in Vaasa, Finland. Occasional in-person sessions if you’re nearby.

What success looks like (first ~90 days)

• You can ship independently across mobile + backend + cloud
• Production is more stable and releases are smoother
• At least one meaningful integration or core feature shipped end-to-end
• Basic product measurement is “good enough to trust” for decisions (not perfection)

Compensation

Typically €5,500–€7,500 / month (gross, Finland employment) depending on scope/experience. Equity/options might be possible, case-by-case.

How to apply

Apply by email:

• Email:
• Include: short intro + links (GitHub/portfolio) + 1 project you shipped end-to-end (what was hard + how you solved it)
• Optional: any integration/payments/measurement work you’ve done

Subject line suggestion: Lead Full-Stack Engineer

• Your Name

We fill the role as soon as we find the right person.