Helio Energy
Offline-first field service app for 900 installation engineers
A React Native app for solar installers working in basements and rural sites with no signal. Local-first data model, durable job queue and photo evidence capture that syncs whenever the phone finds a network again.
Results
- Job completion time
- -42%Job completion time
- Crash-free sessions
- 99.6%Crash-free sessions
- Jobs lost since launch, from ~40/month
- 0Jobs lost since launch, from ~40/month
- Invoicing lag, from 48 hours
- 15 minInvoicing lag, from 48 hours
The challenge
What we walked into.
Helio's 900 installation engineers spend their days in basements, roof spaces and rural sites. Connectivity is not intermittent so much as absent for hours at a time.
The app they had was a web view in a native shell. It lost job data whenever a connection dropped mid-save, so engineers kept paper backups and re-keyed everything in the evening, unpaid and error-prone. Photo evidence for warranty claims frequently never arrived at all.
Because completion data reached Dynamics up to 48 hours late, invoicing lagged the work by two days across the whole field organisation.
The approach
What we actually did.
- 01
Local-first, not offline-tolerant
SQLite on the device became the source of truth rather than a cache. The app is fully functional with the radio off; synchronisation is a background concern the engineer never has to think about.
- 02
A queue that survives a force-quit
Every mutation is appended to a durable outbound journal before it executes. If the OS kills the app mid-upload, the queue resumes from the last known good entry on next launch.
- 03
Conflict rules decided up front
Server wins on pricing and scheduling, device wins on field observations, and anything else lands in an exception queue a human reviews. Agreeing this before build removed weeks of ambiguity.
- 04
Evidence capture that completes
Photos are compressed on device and uploaded in resumable chunks, so a warranty pack finishes even over a single bar of 2G.
- 05
Release engineering
Fastlane pipelines, staged rollout and kill switches, plus a device matrix weighted to the low-end Android handsets the field team actually carries.
Stack
- React Native
- SQLite
- TypeScript
- Azure
- Dynamics 365
- Fastlane
Our engineers work in basements with no signal. Blocify was the first team that treated that as an architecture problem instead of an excuse.
Tomas R.
Head of Field Operations, Helio Energy
Practices used
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