Founding-team engineer at Zellify

Stockholm/London. 6th engineer

Why Zellify?

Apple and Google control how the world discovers and pays for apps. They set the rules, take 30%, and decide who wins. For developers and publishers, that's not a distribution platform, it's a chokepoint. Zellify exists to break that dependency. We're building the infrastructure that lets app developers bypass the gatekeepers entirely.

This is a rare opportunity to help build a company at the exact moment the rules are changing. Regulators are forcing the app stores open. The duopoly's grip is loosening for the first time in a decade. Developers are ready to move. We're building what they move to.

We're AI-native in two directions. The platform: customers describe a funnel in English and the system generates the whole thing — quizzes, paywalls, copy, layouts, variants. AI is the substrate the rest of the product runs on, not a feature bolted on top. The team: Claude Code and Cursor as default tools, not occasional helpers, and a hiring bar that assumes you treat AI as leverage rather than threat.

Our team is small and unreasonably focused. No layers, no politics, no inherited playbook. Everyone ships, everyone owns outcomes, and everyone talks directly to the customers we're building for. If you're the kind of person who'd rather take on Apple and Google than optimize someone else's dashboard, you should join us.

The longer game

Mobile subscription apps are the wedge — they have the urgency, the budget, and the pain points that lets us land. The platform underneath is the durable thing: a cross-vertical web transaction network with a first-party identity graph. Telehealth, fintech, insurance, online education — they all need the same primitives. High-converting web funnels. Server-side attribution that survives iOS 14.5. Identity that's portable across acquirers.

Push the timeline further and it's an ad network. Once we sit in funnels across hundreds of subscription apps with portable first-party identity, every verified subscriber becomes high-intent audience for every other app on the network — at conversion rates the open web can't touch. The wedge sells funnels. The endgame sells distribution back to the apps that fled the gatekeepers in the first place.

What you'll own

The funnel-rendering platform. Next.js + edge runtime, what our customers' end-users actually see. Page load, payment-page conversion, A/B variant routing. A 1% conversion lift on a $2M/month customer funnel is $240K/year. Per customer.

Server-side attribution. The Meta CAPI pipeline. Sub-second event delivery, dedup between client pixels and server events, click-ID propagation, deterministic match-keys across web → checkout. This is the system iOS 14.5 broke for everyone else. We make it work.

The sequential A/B testing engine. Always-valid p-values, mSPRT-style peeking without inflating false-positive rates. v0 today. You take it to v1.

First-party identity primitives. The thing that makes Zellify a network, not a tool. You'll architect this with Nils and Marcus.

Engineering culture. TypeScript monorepo conventions, observability stack, code-review norms, AI-tooling defaults. We use Claude Code and Cursor heavily and have opinions — bring yours. The next 3–5 engineers inherit what you set.

Customers, directly. Shared Slack with growth leads at our customer apps. You'll fix things in production while they watch, and ship features they asked for in the same week.

You'll thrive here if

You've shipped something real 0→1 — a startup, a serious side project, an internal tool that became a product. You're fluent across the TypeScript stack (Next.js, Node, Postgres, edge) and unbothered by payments plumbing, webhook chaos, or third-party API edge cases. You have opinions about latency, Core Web Vitals, and where to leave tech debt deliberately. You write well — RFCs, customer messages, post-mortems. You treat AI tools as leverage.

You want to be one of the names on the company. Not engineer #6 with a roadmap handed down.

You won't thrive here if

You expect clean requirements and narrow ownership. The role spans the rendering platform, the attribution pipeline, the testing engine, customer Slacks, and culture-setting — sometimes in the same week. Big-company senior engineers often struggle with that surface area, and that's fine. We just want you to know.

You don't need a FAANG badge or ten years of experience. You do need taste, throughput, and the appetite to set direction.

Where, and how often

5-6 days a week in-office, minimum. We're at the stage where being in the room matters and we'd rather be honest about that than wave at "hybrid" and let it drift. Travel between offices is frequent and on us.

Compensation & perks

• Base: Senior IC market rate

• Founding-team equity. Real numbers on the first call.

• 30 days paid vacation

• ITP1 pension (Sweden) or equivalent UK arrangement

• Private health insurance (Sjukvårdsförsäkring)

• 5,000 SEK Friskvårdsbidrag

• Top-spec laptop, monitor, whatever equipment you need

• All AI tooling covered

• Conference and learning budget

• Quarterly team offsites

How to apply

Email [email protected] with:

• LinkedIn or CV

• A system you built and are still proud of — link, screenshots, or two paragraphs

• How AI tools currently fit into your daily workflow

• Why Zellify, in three sentences

We close fast on candidates we like.