Energy & Utilities · Mobile

Cross-Platform
Field Service App

How we replaced paper-based equipment inspections with an offline-first React Native app — cutting report turnaround from 5 days to 4 hours and eliminating $180K in annual rework.

95%Faster Reports

100%Offline Capable

$180KRework Eliminated

340+Field Users

Overview

Client Context

A mid-Atlantic energy utility with 340 field technicians conducted 2,800 equipment inspections per month across substations, transmission lines, and distribution infrastructure. Every inspection was recorded on multi-page paper forms, photographed with personal phones, and transcribed into SAP PM back at the office — often days later.

Many sites had zero cellular connectivity. Technicians would complete a week of inspections, drive back to the regional office, and manually enter data from crumpled, rain-smeared forms. Transcription errors were common — wrong asset IDs, illegible readings, missing photos. 12% of inspections required rework because the data was unusable.

The client needed a cross-platform mobile app that worked identically on iOS and Android, functioned with zero connectivity, auto-synced when back online, and integrated with their existing SAP system.

React Native TypeScript WatermelonDB Expo Node.js / Express PostgreSQL SAP PM (RFC) Azure Blob Storage

The Challenge

Paper in the Rain

Field technicians work in every weather condition — climbing transmission towers in rain, inspecting substations in freezing temperatures. Paper forms don't survive these conditions. Neither does reliable cellular data.

📱 Zero Connectivity

60% of inspection sites had no cellular coverage. Technicians needed a solution that worked entirely offline for days at a time, queue-syncing when connectivity resumed.

📝 Paper Degradation

Multi-page inspection forms were routinely damaged by weather. 12% of completed inspections couldn't be transcribed due to illegible handwriting, water damage, or missing pages.

⏱️ 5-Day Report Lag

Average time from inspection to SAP entry was 5 business days. During peak storm season, the backlog extended to 2 weeks — making compliance reporting impossible.

🔧 Dual Platform

55% of technicians used company-issued iPhones, 45% used Android devices. The app needed to run identically on both platforms with native performance — no compromise on speed or UX.

The Solution

Offline-First Mobile Platform

We built a React Native app with WatermelonDB providing a full local SQLite database on-device. Every inspection, photo, and reading is stored locally first and synced when connectivity returns — even if that's days later.

01 — WatermelonDB Offline Engine

Full relational database on-device with lazy loading and observable queries. The entire asset catalog (14,000 assets) syncs incrementally. Inspections queue locally with conflict-free merge on reconnect.

02 — Dynamic Inspection Forms

Form schemas defined in JSON and stored on-device. Different asset types render different inspection checklists — substations show breaker tests, transmission lines show clearance measurements. No app update needed to add new form types.

03 — Photo & GPS Capture

Inline camera capture with GPS tagging, timestamps, and asset association. Photos compress to 200KB on-device before sync. Geo-fencing validates that the technician is physically at the correct asset location.

04 — SAP PM Integration

Middleware layer translates inspection records into SAP PM notifications and orders via RFC. Bi-directional sync ensures work orders created in SAP appear in the mobile app and completed inspections close orders automatically.

Technical Deep-Dive

Offline Sync Architecture

The core challenge was conflict resolution during sync. Multiple technicians might inspect the same asset offline. We implemented a last-write-wins strategy with server-side conflict detection and a review queue for true conflicts.

WatermelonDB Sync — InspectionModel.ts

import { Model, Q } from '@nozbe/watermelondb'; import { field, date, relation, children } from '@nozbe/watermelondb/decorators'; export class Inspection extends Model { static table = 'inspections'; static associations = { assets: { type: 'belongs_to', key: 'asset_id' }, readings: { type: 'has_many', foreignKey: 'inspection_id' }, photos: { type: 'has_many', foreignKey: 'inspection_id' }, }; @field('asset_id') assetId!: string; @field('status') status!: 'draft' | 'complete' | 'synced'; @field('sync_status') syncStatus!: 'pending' | 'synced' | 'conflict'; @field('latitude') latitude!: number; @field('longitude') longitude!: number; @date('inspected_at') inspectedAt!: Date; @date('synced_at') syncedAt?: Date; @children('readings') readings!: Query<Reading>; @children('photos') photos!: Query<Photo>; @relation('assets', 'asset_id') asset!: Relation<Asset>; } // Sync engine — runs on connectivity change export async function syncInspections(db: Database) { const pending = await db.get<Inspection>('inspections') .query(Q.where('sync_status', 'pending')) .fetch(); for (const inspection of pending) { const photos = await inspection.photos.fetch(); await uploadPhotos(photos); // → Azure Blob await pushToServer(inspection); // → REST API await pushToSAP(inspection); // → RFC adapter await inspection.update(r => { r.syncStatus = 'synced'; r.syncedAt = new Date(); }); } }

The app stores up to 2 weeks of inspection data offline, including 500+ compressed photos. Background sync triggers automatically when WiFi or cellular is detected, using exponential backoff on failures. Technicians never need to think about connectivity — the app just works.

Results

Measurable Impact

The app launched to 50 technicians in a controlled pilot, expanded to all 340 within 6 weeks. Paper forms were fully retired 90 days after launch.

Metric	Before	After	Improvement
Report Turnaround	5 business days	4 hours (avg)	▲ 95% faster
Inspection Rework Rate	12% of inspections	0.8%	▲ 93% reduction
Daily Inspections/Tech	6 inspections	9 inspections	▲ 50% throughput
Offline Capability	Paper only	Full functionality	▲ 100% digital
Photo Documentation	Personal phones, unlinked	GPS-tagged, auto-linked	▲ 100% traceable
Annual Rework Savings	$180K/year waste	$12K/year	▲ $168K saved

Client Feedback

Our technicians work on 138-foot towers in January. Paper forms were literally freezing in their hands. The app changed everything — they complete inspections in half the time, the data is perfect, and we haven't had a single compliance miss since launch. The offline sync is magic — guys work all week in zero-service areas and everything just appears in SAP when they're back in range.

Field Operations Director

Mid-Atlantic Energy Utility — 340 Technicians

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Cross-PlatformField Service App