App Development

Title: Senior React Native Engineer to Stabilize and Own an Existing Field Mapping App (Mapbox + Supabase) About the project I have a tree-mapping and field survey app in beta on both iOS and Android, with a web admin panel. It is built in React Native with Mapbox, backed by Supabase, with the admin web app on Vercel. The app is feature-complete and in active beta use. I am looking for one senior engineer to take ownership of the existing codebase, fix a set of persistent reliability issues, and carry it to a stable production release. This is a takeover and stabilization role, not a build-from-scratch role. What you'll inherit and own An existing React Native + Mapbox mobile app (iOS and Android) and a Supabase backend with RPCs, row-level security, soft-delete, and database triggers A web admin panel on Vercel for reviewing and exporting field data The work, in priority order Data integrity: surveys must save and stay saved. Right now species and measurement edits sometimes revert after save. Sync and conflict handling: mobile and web fall out of sync. Deletes on one client do not always reflect on the other. I need reliable reconciliation between offline field capture and the server. Soft-delete and cascade logic: tree and observation lifecycle (including imported trees and empty-tree pruning) needs to behave consistently. Data hygiene: purge test and dev data from production views and lock down how it can reappear. Map performance and correctness: clustering, viewport queries, and pin accuracy, including fixing incorrect counts and misplaced pins. Hold the fixes. I have had the same bugs come back after being reported fixed. I need someone who works with tests and does not regress. Required experience (address these directly when you apply) Taking over and stabilizing an existing React Native production codebase, not just building new ones Mapbox in React Native (@rnmapbox/maps), including clustering and performance with large pin counts Supabase or deep Postgres: RLS, RPCs, triggers, and migrations Offline-first data capture with real sync and conflict resolution Debugging persistent, hard-to-reproduce data and sync bugs in shipped apps TypeScript end to end, and App Store plus Play Store release experience Bonus ArcGIS or GIS experience (there is an existing ArcGIS dashboard with raster layers I may want to bring into the app) Scientific or ecological data work (Darwin Core, GBIF, taxonomic data models) How to apply Skip the generic pitch. I want: A field or mapping app you have shipped, with link or screenshots, and what you built on it, and a showcase of your GIS experience A specific case where you inherited a messy or unstable codebase and made it reliable, and how How you have handled offline capture and sync conflicts in a real app Your depth with Supabase or Postgres RLS, RPCs, and triggers Applications that do not address the sync, data-integrity, and inherited-codebase questions will not be considered. Engagement: This starts as 10-20 hours per week for 1-3 weeks with ongoing management and stabilization at roughly 1 to 5 hours per week through the rest of this year, with strong potential to expand to 15 to 20 hours per week in 2027 as the next phase of the project begins. I am looking for someone who wants a stable, long-term working relationship, not a one-off fix.