Property Inspection Platform

Field inspectors operate in environments where cellular connectivity is unreliable — basement mechanical rooms, rural property sites, and multi-story buildings with poor signal penetration. The mobile application was designed offline-first from the ground up, meaning every inspection workflow functions completely without network access and treats connectivity as an optimization rather than a requirement. When an inspector opens their daily assignment list, property details, compliance templates, and previously synced reference data are served from local storage via Redux Persist backed by AsyncStorage on iOS and SQLite on Android.

The offline queue architecture captures every mutation — checklist item completions, photo captures, text notes, severity ratings, and inspection status changes — as immutable action records appended to a local queue. Each action carries a client-generated UUID, timestamp, device identifier, and the full payload required for server reconciliation. When connectivity is detected through a network state listener, a background sync service processes the queue in chronological order, posting each action to the NestJS API with retry logic and exponential backoff. Failed actions after maximum retries surface in a sync status panel where inspectors can review errors and manually trigger re-submission.

Conflict resolution handles the edge cases where an inspector modifies an inspection that was simultaneously updated by a manager on the web dashboard. The server applies a last-write-wins strategy for simple field updates but escalates structural conflicts — such as an inspection reassigned to a different inspector while the original inspector was offline — to a conflict resolution queue visible to operations managers. Photo uploads use a resumable chunked upload protocol: images are compressed to 80% JPEG quality on-device before entering the upload queue, and each chunk is tracked independently so a dropped connection mid-upload resumes from the last confirmed byte rather than restarting the entire file transfer.

Compliance checklists are the operational core of the platform, and they needed to be flexible enough to accommodate different property types, state regulations, and client-specific requirements without custom development per account. We built a template engine where operations managers define checklist structures through the web dashboard — sections, items, response types (pass/fail, numeric measurement, text note, photo required), and conditional visibility rules that show or hide items based on previous answers. Templates are versioned so that inspections in progress retain their original checklist structure while new inspections pick up the latest regulatory updates.

Photo documentation goes beyond simple image capture. Inspectors use an integrated annotation tool to draw arrows pointing to defects, place text labels identifying specific building components, and apply severity color coding (green, yellow, red) that carries through to generated reports. Each photo is automatically geotagged and timestamped, linked to the specific checklist item it evidences, and organized into property-level galleries accessible from both mobile and web interfaces. EXIF metadata is stripped before cloud upload to protect inspector privacy while retaining the platform-generated location and timestamp attributes for audit purposes.

Geofencing verification adds a trust layer to inspection data integrity. When an inspector attempts to begin an inspection, the application verifies their GPS coordinates fall within a configurable radius of the property's registered location. If the inspector is outside the geofence, the app displays a warning with the distance to the property and requires a supervisor override code for remote inspections such as drive-by exterior assessments. This feature reduced fraudulent check-ins — where inspectors marked properties as visited without being on-site — and provided property managers with confidence that inspection data corresponded to actual site visits.

The web dashboard serves operations managers, property managers, and client stakeholders who need aggregate visibility across inspection portfolios. The real-time layer uses WebSocket connections managed by a NestJS gateway, pushing events for inspection status changes, photo uploads, sync completions, and overdue task alerts to connected dashboard clients. When WebSocket connections fail — common on corporate networks with aggressive proxy configurations — the dashboard falls back to polling with adaptive intervals that increase frequency during active business hours and decrease overnight to reduce server load.

Route optimization integrates the Google Maps Directions API with a custom scheduling engine that assigns daily inspection routes across inspector territories. Managers define inspector home bases, working hours, and skill certifications (some inspections require licensed specialists), and the system generates optimized routes minimizing drive time while respecting appointment windows for tenant-accompanied inspections. Inspectors receive their route as an ordered task list on mobile with turn-by-turn navigation deep links, and managers can reassign tasks mid-day with push notifications to affected inspectors whose devices update their local queue on next sync.

Report generation runs asynchronously through Bull queue workers to avoid blocking API requests during PDF compilation. When an inspection is marked complete and passes validation — all required checklist items answered, mandatory photos attached, supervisor sign-off if configured — a job enters the report queue. The worker renders an HTML template with Handlebars populated by inspection data, property details, annotated photo galleries, and compliance summary tables, then converts to PDF using Puppeteer with print-optimized CSS. Generated reports are stored in S3 with access controlled by role-based permissions, and distribution rules automatically email PDFs to configured stakeholder lists within minutes of inspection completion.