15. Sync inspections from offline field teams

The brief

Design an offline-capable field-inspection service. Inspectors edit a checklist and attach photos on mobile; supervisors can correct the same inspection in the web app. Define which conflicts are safe to merge and which need a human decision.

• 12,000 inspectors each complete up to 20 inspections/day with eight 3 MB photos per inspection.
• Devices can remain offline for 48 hours and may have unreliable clocks.
• After a supervisor accepts an inspection, historical signed-off content must remain auditable even if a correction is requested.

Constraints

Offline support≥ 48 hours

Declare the supported offline duration, including queued writes and retained sync history.

Accepted record history

Corrections must not silently replace accepted evidence.

Concurrent changes

Do not silently discard conflicting checklist values based only on device timestamps.

Resumable photos

An interrupted upload must not require replaying every photo or expose another inspection’s files.

What to cover

1. 01

   Sync protocol

   Define client operations, server acknowledgements, cursors, retries and tombstone retention.

2. 02

   Conflict examples

   Work through same-field edits, attachment additions and a correction after sign-off.

3. 03

   Data and access

   Describe revision history, authorization and staged/resumable photo attachment.

4. 04

   Capacity and recovery

   Calculate daily photo volume and an offline reconnect burst; state quotas and recovery behavior.

Worked designs

No worked design has been published for this brief yet. You can start an attempt and share your approach in the discussion.

Review rubric

AI feedback uses these criteria. Scores are practice feedback.