04 / Field-Service Ops — Case Study

Enforcement‑First Field‑Service OS

An operations platform for an electrical, security, AV & telecom group — dispatch, workforce, assets, procurement and dual-sided billing behind one decision engine.

RoleSole Architect / Full-Stack
TimelineMay 2026 — Present
ClientAustralian multi-entity trade group
Shape16-workspace Turborepo · 3 apps
ETG admin dashboard and technician app
The Brief

Stop margin leakage before it ships.

Unbilled supplier costs and scheduled-vs-actual billing gaps were leaking an estimated $5k a week. ETG puts one pure, unit-testable decision gate between the API and every workflow — every dispatch, closeout and invoice transition is evaluated, and every block or manager override lands in an audit trail.

Dispatch board — 8-check enforcement gate + manager overrides
Workforce — timesheets, closeouts, licences, AU award engine
Supplier billing + scored two-hop bank reconciliation, with golden-rule gates so a job can't reach ready-to-invoice until its costs are accounted for
Asset / inventory register, quoting, service tickets — one 106+-model schema
Architecture & Stack

One enforcement gate behind every workflow.

Next.js UIWeb app
Fastify · tRPCType-safe API
evaluateDecisionEnforcement gate
Prisma · PostgresData
BullMQ WorkerAsync jobs
Stack
Frontend
Next.js 16React 19
Backend
Fastify 5tRPC 11Prisma 7
Data
PostgreSQLBullMQRedis
Infra
Better AuthAirwallexDockerRailway
Key Decisions
01One shared enforcement gate (evaluateDecision) across dispatch, closeout & billing — structured failure codes, audited overrides
02Money modelled as BigInt integer cents (ex-GST)
03Event-driven workers with dead-letter queues
Walkthrough

Across admin & field.

Technician App · Mobile
ETG technician job acceptance
Accept job & site brief
ETG technician working view
On the clock & evidence
ETG technician schedule
Upcoming schedule
Admin & Field · Web
ETG scheduling command centre
Admin — scheduling command centre
ETG admin dashboard
Admin dashboard — live operations
ETG invoicing
Invoicing — dual-sided billing
ETG technician web portal
Technician web portal — job view
$300K+Yearly leakage stopped
400+tRPC procedures
1.5K+Automated tests

Stops an estimated $300K+ of annual margin leakage by blocking unbillable or non-compliant work before it ships — backed by 1,200+ unit and 300+ Playwright tests across one audited decision gate.

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