The Product

Exequtech OS is the field service management (FSM) platform my company builds for South African trade businesses — electricians, plumbers, HVAC and solar installers. Job cards flow into quotations and invoices; technicians clock time and log trips; stock and assets are tracked across sites. One Go API serves three clients: the operator web app, a marketing/auth console, and the Exequ-Jobs Android app.

The Interface is an Operating System

The operator app doesn't use the usual sidebar-and-tables SaaS layout. It is a desktop: draggable, resizable, snapping windows; a taskbar; a start-menu app grid — a pattern I first built for CogniFlight's ground station. Billing, Jobs, Assets, Contacts, Reports and Settings are "apps" you open side by side — because a dispatcher genuinely works that way, quoting in one window while checking a technician's clock-ins in another.

Under the hood it's React 19 + TypeScript (strict) with the React Compiler, Apollo Client with full codegen typing against the GraphQL schema, virtualized data grids for large tenants, in-browser PDF generation and barcode scanning. A Playwright-based profiling harness tracks heap, CPU and leak baselines so the window manager stays fast as the platform grows.

Tenant Isolation at the Database Layer

Multi-tenancy is enforced where it can't be forgotten: in PostgreSQL itself. This is Brian Felgate's design — he leads our Go backend — and living with it has permanently changed how I think about isolation. Every request opens a transaction and stamps it with the caller's identity via set_config; row-level-security policies and audit triggers then scope every query and record every change.

// Every transaction is stamped with the caller's tenant before any query // runs; RLS policies enforce isolation below the application layer. func setAuditContext(ctx context.Context, tx pgx.Tx, data *Ctx) error { if data.Tenant != nil { if _, err := tx.Exec(ctx, "SELECT set_config('audit.tenant_id', $1, true)", data.Tenant.ID.String()); err != nil { return fmt.Errorf("failed to set audit.tenant_id: %w", err) } } // member_id, request_id and reason follow the same pattern, // feeding the trigger-based audit trail. return nil }

A forgotten WHERE tenant_id = ? in application code therefore leaks nothing — the database refuses to return foreign rows. The same session variables drive an immutable, trigger-based audit log tied to request identity.

Other Pieces of What We've Built

• Schema-first GraphQL with two surfaces — a console API for account/tenant management and a tenant API for the business domain, both generated with gqlgen from 18 schema files.
• A server-side document engine that renders quotations, invoices and job-card reports to PDF through a themeable template system.
• An MCP server wrapping the API, so AI agents can operate the platform through the same permission model as humans.

My Role

I co-founded Exequtech and lead the product's web side: the operator app and the console are primarily my commits (561 on the web platform), and I built the Android client, AI-assisted. My co-founder Gerhard van Staden builds on the web platform with me — and with years of web development and client consulting behind him, he's also the one who mentors me in both. Hosting and deployment are Brian's domain — he manages the production environment hands-on and double-checks the security himself, which is deliberate: it's how we keep the risk managed while working with AI this heavily. We build Exequtech in our free time — a small crew testing our limits — but the users are real, so the standards are too. I work with Claude Code daily; the deal is simple: it types fast, I review, decide, and answer for what I ship.