Construction · United States
Schema-per-tenant Django architecture with PostGIS geofencing for automatic clock-ins, payroll and invoicing automation, a crew mobile app, and a Stripe webhook state machine for subscriptions and affiliate payouts.
A management platform for construction companies: projects, tasks, crews, timesheets, leave, payroll, invoicing and inventory in one system, with a mobile app for workers in the field. Each company signs up as its own tenant, pays per staff member, and can be referred in by affiliates who earn a commission.
Construction firms were running crews from spreadsheets and paper timesheets. The product needed strict separation between companies (payroll data for one firm must never be visible to another), a time clock that didn't rely on workers remembering to punch in, and billing that scaled with headcount. We built the backend and the APIs that the web and mobile apps run on, and have maintained it since.
How the system is layered, from the people using it down to the data and the services it depends on.
The choices that made the difference, and why we made them.
Each company lives in its own PostgreSQL schema. A query can't cross tenants because the connection's search path only contains one company's schema. JWTs are issued with the tenant baked in and verified against the resolved tenant on every request, so a token for one company can't be replayed against another.
The tenants backend and the PostGIS backend both wrap Django's Postgres backend, and you can only pick one engine. We wrote a small custom backend that inherits from both, which lets spatial fields work inside every tenant schema. Geofence matching is then a single database query: the nearest site whose radius contains the worker's location.
The mobile app reports significant location changes; the backend matches them against site geofences and opens or closes a punch automatically. Manual entry dropped and accountability rose by more than 40 percent, because the record reflects where people were, not what they remembered.
Stripe delivers events out of order, late and more than once. A webhook state machine reconciles six-plus event types into a single subscription state per tenant, with tiered per-staff pricing and automated affiliate commission payouts fired on activation.
Tell us what you're building. You'll get a straight answer on scope, timeline and cost, usually within one business day.