Senior Next.js / Supabase Developer to Maintain & Extend a Live SaaS (Ongoing)

We have a live, revenue-generating SaaS and need an experienced full-stack developer to take over its ongoing maintenance and feature development. The original developer built it end-to-end and is handing over a fully documented codebase — you'd become the sole engineer on the product. It is a marketing-attribution platform. It captures form submissions from clients' WordPress sites, tracks which marketing channel produced each lead, and matches Xero invoices back to those leads to report real revenue per channel and campaign. It's in production with paying customers, and billing runs on live Stripe — so this is real, careful work, not a prototype. WHAT THE WORK INVOLVES - Keeping production healthy across Vercel, Supabase, Stripe, and Xero. - Fixing bugs and shipping small-to-medium features against a clean, well-tested codebase. - Maintaining the integrations (Stripe billing, Xero OAuth + invoice sync, Resend email) as those APIs change. - Writing and applying database migrations safely (forward-only, CI-gated). - A documented backlog of enhancements to pick up once you're settled in. TECH STACK (you should be strong in most of these) - Next.js 16 (App Router) + React 19 + TypeScript - Supabase (PostgreSQL + Auth) - Stripe billing (subscriptions, webhooks, trials) - Xero API / OAuth integration (a big plus) - Vercel hosting + GitHub Actions CI - Vitest and test-driven development - Tailwind CSS + shadcn/ui YOU'RE A GREAT FIT IF - You can own a live production app solo and debug it calmly under pressure. - You have real, hands-on Stripe billing experience (or a very close equivalent). - You have a security mindset — this is a multi-tenant app handling payments and customers' financial data. - You write tests as you go and keep CI green. - You communicate clearly, flag risks early, and don't need hand-holding. ENGAGEMENT - Ongoing / long-term, hourly. - Roughly [5-10 hours/week to begin with], flexible. - Remote — please have some overlap with Australian business hours (our product and customers are AU-based). TO APPLY — please include in your proposal (generic copy-paste proposals will be skipped): 1. A production app you've maintained or built solo — a link or a couple of sentences. 2. Your experience with Stripe billing and/or the Xero API. 3. Your availability and hourly rate. Thank you!!