What are the best free supply chain planning tools for testing inventory replenishment workflows?

If your goal is to test inventory replenishment workflows without paying for a full supply chain suite, the best free options tend to fall into two buckets:

1. Open-source planning / simulation tools you can configure yourself
2. Free tiers or trial versions of commercial tools that are good for quick validation

Best free/open-source tools

1. Odoo Community Edition

• Good for: basic demand planning, reordering rules, MRP/inventory workflow testing
• Why it’s useful: you can simulate purchase rules, min/max inventory, lead times, and replenishment triggers
• Limits: some advanced planning features are in paid editions
• Best if you want: an ERP-like environment to test real replenishment processes

2. ERPNext

• Good for: inventory, buying, warehouse, and reorder-level workflows
• Why it’s useful: supports reorder levels, item variants, suppliers, and stock transactions
• Limits: not a sophisticated APS tool, but strong for workflow testing
• Best if you want: a free end-to-end business system for replenishment scenarios

3. OpenBoxes

• Good for: inventory management and replenishment in healthcare/logistics contexts
• Why it’s useful: handles stock levels, reordering, and distribution workflows
• Limits: narrower use case than general ERP tools
• Best if you want: realistic inventory replenishment in multi-location settings

4. FrePPLe Community Edition

• Good for: supply chain planning, demand planning, and inventory optimization
• Why it’s useful: one of the better free planning-focused tools for what-if analysis
• Limits: community edition has restrictions and setup complexity
• Best if you want: a planning engine rather than just transaction workflows

5. Apache Forecast / statistical forecasting toolkits

• Good for: testing demand inputs that feed replenishment
• Why it’s useful: helpful if you need to validate forecast-driven replenishment logic
• Limits: forecasting only; not a full replenishment workflow tool
• Best if you want: to generate demand scenarios and feed them into a planning process

Best free simulation / workflow-testing tools

6. Python + pandas / SimPy

• Good for: custom replenishment logic, reorder point simulation, safety stock testing
• Why it’s useful: fully flexible and free, ideal for stress-testing policies
• Limits: requires coding
• Best if you want: the most control over scenario design

7. AnyLogic Personal Learning Edition

• Good for: discrete-event supply chain simulation
• Why it’s useful: excellent for modeling warehouses, lead times, queues, and replenishment behavior
• Limits: free version has output restrictions and is for learning/non-commercial use
• Best if you want: simulation rather than ERP-style transactions

8. SIMUL8 trial / free demo

• Good for: process simulation of replenishment and warehouse flows
• Why it’s useful: fast to prototype workflow bottlenecks
• Limits: usually time-limited or feature-limited
• Best if you want: quick visual simulations

Free commercial trial options worth checking

These are not permanently free, but useful for short testing:

• Kinaxis trial / sandbox if available
• o9 Solutions demos
• SAP Integrated Business Planning trial environments
• Blue Yonder demos
• Netstock trial

These are usually more useful for evaluating enterprise workflows, but access can be limited.

What I’d recommend by use case

• Need actual replenishment workflow in a free system:
  ERPNext or Odoo Community

• Need planning/optimization rather than ERP transactions:
  frePPLe Community Edition

• Need to simulate policies like reorder point, safety stock, and lead time variability:
  Python + SimPy

• Need visual process simulation:
  AnyLogic PLE

Quick pick

If you want the best free all-around tool for testing inventory replenishment workflows, I’d start with:

1. ERPNext for practical workflow testing
2. frePPLe for planning-centric testing
3. Python/SimPy for policy simulation and scenario analysis

If you want, I can also give you:

• a comparison table
• the best choice for small business vs enterprise
• or a step-by-step setup guide for one tool