Offline-first apps
Offline-first mobile apps that don’t lose your users’ work
Your users work where the signal doesn’t reach: on site, in the field, on the move. I build apps where the phone’s database is the source of truth and sync is designed up front, so work is never blocked by a missing connection and never lost when it comes back.
Opens Cal.com in a new tab.
- field users in 10+ countries on an offline-first app I led
- 20,000+
- data-loss incidents reported in 4.5 years of field use
- 0
- questions in a single inspection, filled in offline
- 500+
- photos per inspection, uploaded in the background
- 1,000+
Who it’s for
Sounds familiar?
- People lose work when the connection drops, or can’t start until it comes back.
- Photos and files upload unreliably, and nobody can tell what actually reached the server.
- A record edited on two devices ends up with one version silently overwriting the other.
- The app works in the office and fails in the field.
How I build it
What makes it hold up in the field
01
Contract before code
I agree the sync contract with your backend team first: payloads, upload semantics and what happens when something fails. Then both sides build against it.
02
The phone is the source of truth
Work is saved to a local database the moment it’s entered. A new record gets a local ID straight away and is remapped when the server assigns one, and retries reuse that ID, so a flaky connection never creates duplicates.
03
Uploads that can’t block each other
Photos go up in the background while people keep working, and a form is only submitted once its media is confirmed. A failed upload is marked, retried and, if it fails again, raised with the user. It never holds up the rest of the queue.
04
Sync people can see
The app shows what’s still uploading, so “I submitted it” and “the server has it” are never confused. When a record was changed on two devices, the user is warned and can keep their version instead of losing it silently.
05
No server at all, when that’s better
Some data shouldn’t leave the phone. HelperBook keeps household wage records on the device only, with user-owned export and restore, which keeps it outside data-fiduciary scope under India’s DPDP Act.
What you get
What’s included
- A data model with the device as the source of truth
- A sync contract agreed with your backend team
- Background upload queues for photos and files
- Conflict handling and sync status people can see
How we start
Paid discovery
A fixed fee of ₹60,000 (US$900) for about a week: audit or product scoping, ending in a plan and estimate.
FAQ
Questions clients ask
Do I need offline-first, or is caching enough?
Caching helps people read data they’ve already loaded. If they need to create or change data without a connection, and that work must not be lost, you need offline-first: a local database, a sync queue and a plan for conflicts.
Can you add offline support to an existing app?
Yes, usually one flow at a time: start with the screens where people create data, move them onto a local database, then add the upload queue and sync. A paid discovery sprint maps which flows matter and in what order.
Android only, or iOS too?
Both. The Pulse offline engine ran in native Android (Kotlin) and iOS (Swift) clients at feature parity, and later in one React Native codebase.
What about sensitive data?
If data doesn’t need to leave the phone, it shouldn’t. HelperBook keeps wage records on the device only, and its crash reports carry no names or amounts.
Tell me where your users lose signal
Tell me what exists today and what you need by when.