KennebecEnergyNext

Energy delivery is a paperwork business that happens in places without signal. Drivers deliver fuel, the office needs invoices, and the network between them is unreliable by geography. KennebecEnergyNext is an Android app that a Kennebec-area energy-distribution company runs in daily field operations.

The design constraint that shapes everything is offline tolerance. The app has to accept a delivery and its invoice data with no connectivity and reconcile later without double-counting or losing work: local-first writes, sync that can be interrupted at any point, and conflict handling that assumes the same record may have moved on both sides.

Around that core: role-based staff access so drivers and office staff see different things, weather-aware planning because delivery routes in Maine are weather-dependent, and PDF paperwork export so the invoicing side still produces the documents the business actually files.

The honest summary of the engineering is that the interesting problems are all about state, not UI. What happens when the phone dies mid-entry. What happens when a record was edited on two devices. What happens when a sync finally succeeds three hours later against a record that changed in the meantime.

What I'd add first if I rebuilt it: instrumentation for sync failures. Offline-tolerant systems fail quietly by definition, and the only way to know your reconciliation logic is right is to count how often it actually runs and what it had to resolve.

No usage numbers are recorded here, so I am not quoting any. What is verifiable is the deployment: the company uses it in daily operations.