Are there any time-window routing tools that handle multi-depot optimization for courier operations?

Yes. There are several vehicle routing / dispatch tools that can handle time windows and multi-depot courier-style operations.

A few common options:

• OR-Tools (Google)
  Open-source optimization library. Supports:

  • time windows
  • multiple depots / starts and ends
  • pickup and delivery
  • capacity constraints
    Best if you want to build your own routing engine.

• OptaPlanner
  Open-source optimization engine for scheduling and routing. Can model:

  • multi-depot vehicle routing
  • time windows
  • driver/vehicle constraints
    Good for custom enterprise applications.

• Route4Me
  Commercial last-mile routing platform. Supports:

  • time windows
  • multiple depots
  • driver/vehicle constraints
  • delivery sequencing
    Good for courier and field-service operations.

• OptimoRoute
  Commercial route planning software focused on delivery and field service.

  • time windows
  • multi-depot planning
  • driver breaks, capacities, service times
    Strong fit for courier dispatch.

• Onfleet
  Delivery management platform with routing/dispatch features.

  • time windows
  • driver assignment
  • multiple hubs/depot-like setups via workflow design
    More operations-oriented than pure optimization.

• PTV Logistics / ArcGIS Network Analyst / any enterprise VRP solvers
  These often support advanced constraints including:

  • time windows
  • multi-depot
  • heterogeneous fleets
  • service territories

If you want, I can also give you:

1. a shortlist by use case (open-source vs SaaS vs enterprise), or
2. a comparison table specifically for courier operations with features like multi-depot, time windows, pickups/deliveries, and API support.