Part-time Senior Full-Stack Engineer – Code Reviewer & Release Owner (Next.js · Firebase · Cloud Run · Payments)

About us Storspay (StorsApp Inc., Calgary) is a B2B cross-border payments platform. Businesses in the US, Canada, UK and Europe use it to pay teams and suppliers in 26 countries across Africa, Asia and Latin America, by bank and mobile money, and to get paid back. We are FINTRAC-registered, backed by Techstars and 500 Global, and live with paying customers. Our code is written with AI coding tools (Claude Code), which open pull requests. We need an experienced engineer to be the human gate: review every change, own releases, and keep production safe. What you'll do 1. One-time setup (first 1–2 days, 10–15 hours): - Branches and auto-deploy: staging and main. Merging to staging auto-deploys to staging with Cloud Build; merging to main deploys to production after a manual approval. - Branch protection and automated tests on every pull request (fees, ledger, balances). - All secrets in Google Secret Manager; staging uses sandbox keys only. - A one-click rollback note (Cloud Run previous revision) a non-technical founder can follow. - Error alerts and budget alerts. 2. Ongoing review (5–8 h/week): - Review pull requests within 24 hours. - Approve every red-zone change before it reaches customers: fees, FX, balances, ledger, payment-partner API calls, KYC/KYB decisions, auth and permissions, Firestore rules, data migrations. - Test on staging against a written checklist, approve production deploys, roll back if needed. 3. On call for production incidents (best effort, agreed response time). Definition of done for the setup phase - No one can push directly to main; every change merges through a reviewed pull request. - Staging deploys automatically from staging; production deploys from main only after approval, via Cloud Build (no laptop deploys). - Zero secrets in the repo or build files; all in Secret Manager. - Tests run on every pull request and block merging when they fail. - A written rollback note tested once on staging. - Alerts configured and tested. Must have - 5+ years full-stack, with production Next.js 14 (App Router) + TypeScript. - Firebase / Firestore (security rules, indexes, transactions) and Firebase Auth. - Google Cloud Run + Cloud Build (CI/CD, revisions, rollbacks), Secret Manager, IAM (least privilege). - Payments or fintech: idempotency, signed webhooks, double-entry ledgers, money as integers/decimals (never floats), reconciliation. - Experience reviewing code you didn't write, including AI-generated code. You catch subtle money bugs, not just style. - Clear written English; you'll explain issues to a non-technical founder. Nice to have - Payment partner APIs (virtual accounts, bank and mobile-money payouts, collections, FX quotes); KYC/KYB providers and AML screening; security reviews (supply-chain/npm risks, secrets hygiene); Africa or emerging-markets payments. How we work - Every change is a pull request with a plain-English summary and a test checklist. - Nobody pushes directly to main. - You never hold production keys in files, notes or screen recordings. - Short written updates; no status meetings unless something is on fire. Paid trial: shortlisted candidates do a paid 2-hour review of a real pull request on our staging code before we agree terms.