Best Open Source Purchase Order Software for Small Business (2026): 6 Tools Compared

Purchase order (PO) software helps you order from suppliers, receive goods and match bills. Small businesses use POs to avoid duplicate orders and to control spending. These open source tools include purchasing as part of a wider system.

We write for small businesses, freelancers and growing teams, not large enterprises. Every tool below was checked on GitHub for license, archive status and recent activity, and prices are never quoted because they change. Our picks are based on each project's documentation and repository data, not on hands-on benchmarks, so always try a tool with sample data first. This is general information, not tax, legal or accounting advice.

Top picks at a glance

• ERPNext: Buying module with purchase orders.
• Odoo Community: Purchase app in Community.
• Dolibarr ERP CRM: Supplier orders for small teams.

What to look for in purchase order software for a small business

• Order to receipt to bill. Look for three-way matching so orders, receipts and bills agree.
• Approvals. Set limits so large orders need approval.
• Supplier price history. Seeing past prices helps you negotiate.
• Stock link. Receiving goods should update stock automatically.
• Project health and license. Choose a project that is not archived, has recent releases and a real open source license. Check the LICENSE file, not just the website.

Comparison table: best open source purchase order software

Stars and update dates are a snapshot from 16 October 2026 and change daily. They show activity, not quality.

The 6 best open source purchase order tools, reviewed

1. ERPNext

Best for: Buying module with purchase orders
License: GPL-3.0 · Stack: Python (Frappe), MariaDB · GitHub: 40,232 stars, repo updated Oct 2026

Create purchase orders, receive goods and match supplier invoices inside a complete ERP.

Read our full guide to ERPNext · Source on GitHub · Official website

2. Odoo Community

Best for: Purchase app in Community
License: LGPL-3.0 (Community edition) · Stack: Python, PostgreSQL · GitHub: 55,072 stars, repo updated Oct 2026

Odoo Community includes a Purchase app for requests, orders and vendor bills.

Read our full guide to Odoo Community · Source on GitHub · Official website

3. Dolibarr ERP CRM

Best for: Supplier orders for small teams
License: GPL-3.0 · Stack: PHP, MySQL/MariaDB/PostgreSQL · GitHub: 7,732 stars, repo updated Oct 2026

Dolibarr manages supplier orders alongside stock and invoices.

Read our full guide to Dolibarr ERP CRM · Source on GitHub · Official website

4. InvenTree

Best for: Purchase orders for parts and stock
License: MIT · Stack: Python (Django), React · GitHub: 7,717 stars, repo updated Oct 2026

InvenTree supports suppliers and purchase orders tied to parts and stock locations.

Source on GitHub · Official website

5. LedgerSMB

Best for: Purchasing in double-entry accounting
License: GPL-2.0 · Stack: Perl, PostgreSQL · GitHub: 570 stars, repo updated Oct 2026

LedgerSMB handles purchase orders as part of its accounting and inventory features.

Source on GitHub · Official website

6. AureusERP

Best for: Newer ERP with purchasing
License: MIT · Stack: PHP (Laravel, Filament) · GitHub: 12,073 stars, repo updated Oct 2026

AureusERP lists purchasing among its modules. Evaluate maturity before relying on it.

Source on GitHub · Official website

Open source vs paid purchase order software

Paid cloud products usually win on polish, mobile apps, automatic bank connections and support. Open source wins on running cost as you grow, data ownership and the freedom to customize. The real cost of open source is hosting, backups, updates and your own time, so count those honestly. Several of these projects also sell hosting or support if you would rather not run a server yourself.

How to choose the best purchase order software

• You want purchasing, stock and accounting together: ERPNext.
• You make products from parts: InvenTree.
• You already use Odoo: Odoo Community Purchase app.
• You want a light suite: Dolibarr.

Mistakes to avoid

Set up supplier records, tax and approval limits before you start. Without a clear process, purchase order software only adds paperwork.

Where to host it

All of these tools can be self-hosted. A small VPS or a web hosting plan from a provider such as Hostinger is enough to get started with most of them. Check each project's requirements first, and read our security and backup checklist before you add real data.

Related comparisons

• Best Open Source Vendor Management Software (2026)
• Best Open Source Accounts Payable Software (2026)
• Best Open Source Inventory Management Software (2026)
• Best Open Source ERP Software for Small Business

All open source business software comparisons

• Accounting
• Bookkeeping
• Billing
• Invoicing
• Payroll
• Inventory Management
• Warehouse Management
• Expense Tracking
• Spend Management
• Accounts Payable
• Accounts Receivable
• Cash Flow Management
• Bank Reconciliation
• Purchase Order
• Vendor Management
• Point of Sale (POS)
• Time Tracking
• Quotation & Estimates
• Revenue Recognition
• Financial Reporting
• Asset Management
• Lead Management
• Sales Pipeline
• ERP

Also see our directory of 50 open source CRMs.