Your site visit, even with no signal

For buyers visiting a project. Tick the checklist, take photos (each gets GPS and time), add notes. Every entry is fingerprinted and chained to the one before it on your phone, so nothing can be changed later without it showing. At the end, sign and export a JSON and a PDF. Nothing is uploaded, ever, unless you send the file yourself.

Open this page once with signal and it keeps working offline. On a phone, use "Add to Home Screen" to keep it as an app.

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Check an exported visit

Pick a .json export (yours or one you were sent). This page recomputes every fingerprint and the chain, then checks the signature. Nothing leaves your device.

How the record works

Each entry (a tick, a note or a photo) is written as a short canonical line with its time, GPS fix and the SHA-256 of the photo, plus the fingerprint of the entry before it. Its SHA-256 is the next link. Change, delete or reorder any entry and every later fingerprint stops matching.
The export is signed over the last fingerprint. With a passkey, your phone's secure chip signs after Face ID, a fingerprint or the screen lock. Without one, a signing key made on this device is used; its private half cannot be exported from the browser.
Time comes from your phone's clock and position from its GPS: we cannot prove either without a network. What the chain proves is that nothing was edited after it was recorded on this device.
Everything lives in this browser's storage on your device. Clearing site data deletes it, so export before you do.

Checklist items come from the checklist our agents use on site and the before-you-sign checklist. Want a professional to go instead? Book a Kolaboro agent.