Expert Full-Stack Developer for SaaS Platform - (PostGIS, React, IoT, Multi-Tenant)
Budget: $1,500 – $3,000 CAD
We are building a production-grade, multi-tenant SaaS platform for environmental project monitoring, reporting and verification. The platform serves organisations generating verified environmental credits across multiple project types — blue carbon, clean cooking, biochar, renewable energy storage, agriculture and biodiversity — and connects programmatically to international carbon credit registries.
We have a completed 100-page technical specification covering every database table, API endpoint, screen, build step and security requirement. You are executing a fully documented brief, not designing architecture from scratch.
What you will build:
PostgreSQL 15 + PostGIS — spatial data is central to everything on this platform
Multi-tenant white-label architecture — branded subdomain per client, zero cross-tenant data visibility, org-scoping middleware on every database query
40+ JWT-authenticated REST API endpoints with role-based access control across six user roles
Dynamic JSONB-driven measurement forms that adapt to project type without schema changes or redeployment
Offline-capable ranger PWA in English and Swahili with IndexedDB sync and Android home screen installation
IoT data ingestion — HMAC-authenticated webhooks, API polling, immutable cryptographically-hashed raw data store for validator audit trails
Automated report builder producing validator-ready PDFs, background job queue, email and SMS alert routing
Satellite change detection pipeline via Google Earth Engine
React Native native mobile upgrade for field rangers
Carbon accounting microservice (Python) implementing multiple accredited methodologies with Monte Carlo uncertainty quantification
Registry API integration with idempotency enforcement, HMAC webhook verification and two-phase commit ledger
This is one complete, continuous build. The developer works through a numbered 25-step build order from database setup to registry integration. There are no pauses, no handoffs, no separate contracts.
Required skills — all of these, not most:
PostGIS (mandatory — if you have never used it, do not apply), React + TypeScript, Node.js or FastAPI, Mapbox GL JS, Progressive Web App, S3 pre-signed uploads, BullMQ or Celery, pdfplumber, Google Earth Engine (Python), React Native.
Engagement: Fixed price per milestone, not hourly. NDA required before the specification is shared. Estimated 5–7 weeks full-time. Strong performance leads directly to ongoing platform development
To apply, answer both questions:
Describe a production multi-tenant SaaS system you built. How did you enforce tenant data isolation at the database query level?
Have you used PostGIS in production? Give one specific example of a spatial query you wrote and why it required PostGIS.
Generic proposals will not be reviewed.
We have a completed 100-page technical specification covering every database table, API endpoint, screen, build step and security requirement. You are executing a fully documented brief, not designing architecture from scratch.
What you will build:
PostgreSQL 15 + PostGIS — spatial data is central to everything on this platform
Multi-tenant white-label architecture — branded subdomain per client, zero cross-tenant data visibility, org-scoping middleware on every database query
40+ JWT-authenticated REST API endpoints with role-based access control across six user roles
Dynamic JSONB-driven measurement forms that adapt to project type without schema changes or redeployment
Offline-capable ranger PWA in English and Swahili with IndexedDB sync and Android home screen installation
IoT data ingestion — HMAC-authenticated webhooks, API polling, immutable cryptographically-hashed raw data store for validator audit trails
Automated report builder producing validator-ready PDFs, background job queue, email and SMS alert routing
Satellite change detection pipeline via Google Earth Engine
React Native native mobile upgrade for field rangers
Carbon accounting microservice (Python) implementing multiple accredited methodologies with Monte Carlo uncertainty quantification
Registry API integration with idempotency enforcement, HMAC webhook verification and two-phase commit ledger
This is one complete, continuous build. The developer works through a numbered 25-step build order from database setup to registry integration. There are no pauses, no handoffs, no separate contracts.
Required skills — all of these, not most:
PostGIS (mandatory — if you have never used it, do not apply), React + TypeScript, Node.js or FastAPI, Mapbox GL JS, Progressive Web App, S3 pre-signed uploads, BullMQ or Celery, pdfplumber, Google Earth Engine (Python), React Native.
Engagement: Fixed price per milestone, not hourly. NDA required before the specification is shared. Estimated 5–7 weeks full-time. Strong performance leads directly to ongoing platform development
To apply, answer both questions:
Describe a production multi-tenant SaaS system you built. How did you enforce tenant data isolation at the database query level?
Have you used PostGIS in production? Give one specific example of a spatial query you wrote and why it required PostGIS.
Generic proposals will not be reviewed.