Wancemo
Operations software for waste collection, storage tracking, driver/team coordination, status workflows, and administrative visibility across South African municipalities.
PRODUCT & DOMAIN CONTEXT
Wancemo digitizes municipal and commercial waste management logistics. Field teams, collection drivers, facility operators, and administrators rely on the backend to log pickup events, track storage capacities, manage assignments, and maintain operational reporting.
THE CORE ENGINEERING PROBLEM
Operations teams required real-time visibility into collection schedules, depot storage limits, and task completions. The backend needed to enforce clear status state machines for collection workflows while ensuring driver inputs in low-connectivity areas synced reliably upon reconnection.
SYSTEM ARCHITECTURE MAP
Data Flow & Boundary Topology
Field drivers use mobile apps to submit collection events. The NestJS backend validates payload schemas, updates collection records in PostgreSQL, and streams status updates to the operations web dashboard.
Offline-ready Data Sync
Management Overview
Business Logic & State Engine
Operational Data Store
Integration Boundaries & Protocols
SYSTEMS & SERVICES BUILT
Core Backend Modules & Responsibility
Collection Workflow State Engine
A deterministic state machine preventing illegal status jumps (e.g. marking a pickup as Deposited before Collection) and logging timestamped audit trails.
Storage & Capacity Inventory API
Data models tracking waste volumes per depot facility, alert thresholds for capacity limits, and historical dispatch logs.
Admin Operations Dashboard API
Aggregated analytical endpoints supplying real-time metrics on completed pickups, active field units, and regional turnaround times.
Detailed Technical Responsibilities
- •Built and maintained NestJS microservices and PostgreSQL data models for collection records, facility inventories, and driver schedules.
- •Engineered workflow state transitions (Scheduled -> En Route -> Collected -> Deposited -> Verified) with input validation at every step.
- •Implemented role-based access control (RBAC) separating administrative managers, depot operators, and field collection drivers.
- •Provided clean, typed REST API contracts for mobile field apps and admin web dashboards.
ENGINEERING DECISIONS & TRADE-OFFS
Architectural Choices & Rationale
Strict Enums and DB-level Constraints for Status Workflows
Modifying workflow states requires coordinated database migrations.
RELIABILITY & SAFETY MECHANISMS
- •Idempotent batch collection sync allowing driver apps to resend offline logs safely.
- •Role-based access control guarding sensitive facility and user administrative controls.
CHALLENGES & RESOLUTION
Field drivers frequently experienced dead zones during pickups. Designed batch payload endpoints accepting client-side timestamps and UUIDs, allowing offline mobile queues to sync in order once signal was restored.
VERIFIED OUTCOMES
- •Delivered robust operational backend for regional waste logistics.
- •Eliminated status reporting discrepancies across collection crews and central dispatchers.
NEXT SYSTEM IMPROVEMENTS
- •Add automated route optimization services using geospatial GIS routing APIs.
Interested in discussing this architecture or an open backend role?
Reach out via email or review my full experience on my resume.