Mobile App — Offline & Sync | HousingSurvey Pro

Surveyors work in properties with poor or no signal, so the HousingSurvey Pro app is offline-first: the on-site capture a survey needs works without a connection (finalising, AI wording and online lookups still need one), and data syncs when you're back online. Tiered — Basics for how it feels, Deep dive for what happens offline, Technical for how sync and evidence integrity hold up.

Basics — it just keeps working

Open and complete surveys with no signal — readings, photos, notes, assessments and sign-off all work offline.
Your work is saved on the device as you go; nothing is lost if the app closes or the battery dies.
When a connection returns, completed evidence syncs automatically to the management dashboard.

The first time you sign in you need a connection. After that, day-to-day capture works offline.

Deep dive — what works offline

Capture: rooms, readings, photos (hashed on-device), the report sections, and sign-off.
On-device calculations: psychrometrics, HHSRS scoring, condensation and ventilation checks are computed on the device — no server round-trip.
What needs a connection: first sign-in, pulling newly assigned jobs, some lookups (weather/soil/EPC auto-fill), AI features, and the final sync of sealed evidence. Where a lookup can't run offline, you can enter the values and it's recorded as manually entered.

Technical — sync & integrity

Local-first storage: drafts are held in the app's local database and survive restarts; syncing is a background reconciliation, not a blocking save.
Sealing offline: a survey can be finalised offline — the SHA-256 hash and chain are computed on-device by the same canonicaliser the server uses, so the record is already tamper-evident before it syncs. On upload the server verifies the same hash (client/server twin parity), so nothing is trusted blindly. See Evidence integrity.
Conflict-free by design: each survey belongs to one surveyor's device session; sync appends sealed evidence rather than merging concurrent edits.
Photos: captured and fingerprinted locally with EXIF provenance, uploaded when connectivity allows; the hash anchors each image to its record.
Resilience: because field capture doesn't depend on the backend, an outage of the dashboard never stops a surveyor collecting evidence.

Back to the help index.