Senior Full Stack Engineer

About the RoleWe’re looking for a Senior Full Stack Engineer to own the product surface of our end to end: our web app (Next.Js), our mobile app (Expo / React Native), and the TypeScript backend-for-frontend that serves both. You’ll be the most senior product engineer on the team. This is an ownership role. You’ll set the bar for product quality, decide how features are structured across web, mobile, and BFF, and be the person the team looks to when a flow is broken and nobody knows why. Over time we’d like you to become the owner of our mobile app - in addition to the rest of the stack, not instead of it. You’ll ship the user-facing side of things that don’t exist yet in Canada: a chequing account, a card we issue, instant payouts.
What You’ll Be Doing
Own the product surface across web, mobile, and the BFF - architecture, quality bar, observability, and roadmap
Lead the design of new product flows for chequing, card issuance, and instant payouts across every client
Own onboarding and activation end to end - the biggest lever in the company
Make the BFF the single reliable contract for web and mobile: strict schemas, versioning, and backward compatibility for app builds in the wild
Grow into owning mobile: release process, OTA updates, store submissions, and the health of the app
Set the technical bar: review architecture, write the patterns others follow, and push back when something isn’t right
Mentor product engineers through reviews and pairing
Work directly with the CTO and product on what we build next and in what order
What Senior Means Here
You make trade-off calls without waiting to be told, and you’re right most of the time
You surface problems early and specifically - before they hit users
You disagree openly, then commit fully
You multiply the team - patterns, reviews, mentoring - rather than only shipping your own work
You own outcomes, not tasks. If your domain is broken, that’s yours to fix, not someone else’s to notice
Who We’re Looking For
Substantial experience shipping production TypeScript across the stack - React/Next.Js at scale, plus a real backend (Node - Hono, NestJS, Express - with a proper data layer)
React Native / Expo in production, or a strong desire to own it and the judgment to get there fast
You’ve owned a product surface before - not "worked on," owned - through launches, incidents, and redesigns
You care about correctness in ways most product engineers don’t: schemas, auth boundaries, idempotent mutations, money shown right
You have taste, and you can explain it
You already build with AI coding tools every day and have strong opinions about where they fail
You’ve been early somewhere and liked it - you’re comfortable making decisions with 70% of the information and revisiting them when the picture changes
You communicate clearly in writing and don’t need a manager to tell you what matters
Bonus Points
Fintech or another domain where a wrong number is a real problem
Design-system ownership, accessibility, or i18n (we ship in English and French)
Datadog RUM or similar frontend observability
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