Sync and offline work

An inspection rarely takes place under perfect Wi-Fi conditions. Basements, crawl spaces, attics, isolated properties: signal can drop without warning. Lumos is built so that this never slows you down.

This page explains how your data flows between Lumos Capture (on the field) and Lumos Web (at the office), what happens when you lose your connection, and how to verify at any time that nothing is lost.

How sync works

Your data is stored centrally in the Lumos cloud. Lumos Web reads and writes directly to that database. Lumos Capture keeps a local copy on your device, which syncs with the cloud automatically as soon as a connection is available.

Concretely:

Each photo or narrative captured on the field is saved locally on your device immediately.
As soon as an Internet connection is detected, Lumos Capture sends the new content to the cloud in the background.
Lumos Web receives this data right after. If your dashboard or project is open, refreshing the page is enough to see them appear.
Conversely, changes made on Lumos Web (for example a narrative added from your computer) flow down to Lumos Capture at the next sync.

Sync is automatic and silent. You do not need to trigger it manually.

Offline mode on Lumos Capture

Lumos Capture is the only one of the three surfaces that operates fully without a connection.

When your device loses signal:

You keep on taking photos, dictating narratives, navigating between building sections and subsections, annotating your photos.
Everything is saved locally, immediately.
No data is lost, even if you close the app or the battery dies.

Lumos Web, on the other hand, requires a connection to function. If you open Lumos Web without Internet, the app cannot load your data.

For an inspection in a no-coverage area (rural, deep basement, metal-frame building), make sure to open the project in Lumos Capture at least once while connected before arriving on site. The project is then downloaded locally and remains accessible with all its information even offline.

Checking sync status

On Lumos Capture, an indicator visible at all times tells you the sync status:

Synced — all your local data is up to date with the cloud. You can close the app safely.
Syncing — Lumos Capture is sending changes. Stay connected for a few moments.
Offline — no connection detected. Your data is saved locally and will sync as soon as possible.

On Lumos Web, you see cloud data live. If a new photo or narrative captured on the field does not appear, sync from Lumos Capture is probably still in progress. Refresh the page after a few seconds.

In case of a conflict

A conflict can happen when the same piece of information is edited in two places at once (for example, you edit a narrative on Lumos Web while a team member edits it on Lumos Capture without a connection).

Lumos applies the following rule: the last synced edit wins. The previous version remains in the project history, where you can consult it if needed.

In practice, conflicts are rare since you usually work alone on a project at a given moment. For co-inspection, plan not to edit the same section in parallel.

Best practices

To avoid surprises on the field:

Open the project in Lumos Capture at least once before the inspection, in a connected area. The project is then downloaded locally.
Check battery and storage on your device before leaving. About a hundred high-resolution photos can take 1 GB.
Connect to Wi-Fi before leaving the inspection to trigger the final sync. Otherwise, it will happen automatically when you regain 4G/5G or another Wi-Fi.
Do not uninstall Lumos Capture while the indicator shows “Syncing”. Wait for it to switch to “Synced”.

All your data remains encrypted in transit and at rest. It never leaves the Lumos ecosystem without your explicit consent. See Privacy and data for details.