Full-Stack Web Developer (TypeScript)

Feenko is a mobile personal finance app with 100k+ users, backed by Visa. They are looking for a Full-Stack Web Developer to own the web funnel, admin panel, and support site, implementing A/B experiments and integrating payment services.

• Implement and launch A/B experiments across the funnel (landings, quiz, paywall, checkout) from specs and Figma layouts — correct bucketing, clean tracking, zero regressions.
• Own our Stripe and Solidgate integrations (checkout, subscriptions, webhooks, upsells) and integrate new services as we test them.
• Develop the internal admin panel; maintain the support site on the same stack (forms, CSAT surveys, upcoming knowledge base).
• Test before production, keep the revenue path relible, and when something breaks — find the root cause yourself via Amplitude, Sentry, logs, and the database.
• Proactively improve code quality, performance, and delivery speed.

• 3+ years of commercial full-stack development with TypeScript.
• Strong experience with a modern SSR framework — Astro or Next.js.
• Production experience with payment systems (Stripe, Solidgate, or comparable): checkout, subscriptions, webhooks, idempotency, edge cases.
• Web2app / quiz funnels / subscription products: paywalls, upsells, trials.
• Experience with serverless deployments (Vercel or similar) and PostgreSQL.
• Understanding of the technical side of A/B testing: consistent bucketing, no flickering, clean event data.
• Independent full-stack debugging and a habit of testing before shipping.
• English at Intermediate+ level.