01 / Field-Service Ops — Case Study

Enforcement‑First Field‑Service OS

An operations platform for an electrical, security, AV & telecom group — five portals over one decision gate, spanning quote-to-cash, procurement, workforce, assets and dual-sided billing.

RoleSoftware Engineer II · Slidey LLC
ScopeSole architect — greenfield build
TimelineMay 2026 — Present
ClientAustralian multi-entity trade group
Shape3 apps · 25 packages
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.

Five portals — ops, technician, client, subcontractor, and tokenised public links
Quote-to-cash — work requests, quotes, projects, field jobs, invoicing, receivables
Procurement — purchase orders, supplier invoices and credits, stock, scored bank reconciliation
Workforce — scheduling, timesheets, closeouts, licences and inductions, AU award rules
Assets & compliance — registers, site credentials, field checklists, document control
Governance — approvals, alerts, enforcement events, SLA targets, audit log
Architecture & Stack

One enforcement gate behind every workflow.

Clients
Web portalsNext.js 16 · React 19
Technician mobileAccept, clock on, close out
API
Fastify 5 · tRPC 11Type-safe API · Better Auth
Gate
evaluateDecision()One gate: dispatch, closeout, billing
Data & jobs
Prisma 7 · PostgreSQLBigInt cents, ex-GST
BullMQ worker · RedisReconciliation sweeps · DLQ
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

Five portals, one rulebook.

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
$5k/wkBilling leakage closed
1,000+tRPC procedures
30K+Automated tests

Stops an estimated $5k a week of margin leakage by blocking unbillable or non-compliant work before it ships. The same gate runs behind all five portals, so field, client and back office never disagree about a job’s state — backed by 30,000+ tests across 2,200+ files.

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