Open-Source ERP: A Practical Guide for Buyers

"Open source" means the source code is published and you're allowed to use, study, change and share it under the terms of its licence. For ERP, that has some very practical consequences, both good and less good.

What you get

No licence fees. You can run open-source ERP for five users or five hundred without paying per seat.

Control over hosting and data. You decide where the database lives. That matters for data residency, for integration work and for leaving a vendor if you ever need to.

The ability to change anything. If a workflow doesn't fit, a developer can change it. That's a superpower, but use it carefully. See the section on customisation below.

No vendor lock-in on the core. If your implementation partner disappears, another one can pick up the code.

What you take on

Responsibility for operations. Backups, security updates and performance are your problem, or your hosting provider's.

Upgrades. Moving between major versions is more work without a vendor-run upgrade service.

Picking modules. Open-source ecosystems have thousands of add-ons of mixed quality. Choosing well takes some experience.

Open core vs fully open

Not every open-source ERP is open in the same way.

• Open core. A free community edition with a paid edition on top. Odoo is the best-known example: Odoo Community is LGPLv3, while Odoo Enterprise adds proprietary apps.
• Fully open. Everything is in the open-source version, and the company earns from hosting and support. ERPNext works roughly this way.

Neither is better by default. Open core often means a larger, better-funded product. Fully open means fewer features behind a paywall.

Licences in one paragraph

Odoo Community uses LGPLv3. ERPNext uses GPLv3. Dolibarr uses GPLv3. iDempiere uses GPLv2. For a business running the software internally, these are almost interchangeable. The differences matter if you distribute modified versions or sell modules, in which case get proper legal advice.

The customisation trap

Because you can change anything, it's tempting to change everything. Don't. Each modification is code that has to be carried forward through every upgrade.

The rule we follow:

1. Use standard configuration first.
2. Change the process before changing the software, where that's reasonable.
3. Use well-maintained community modules (for Odoo, the OCA repositories are a good first stop).
4. Write your own module only when the first three don't work, and keep it small.
5. Never edit core files directly.

Is open-source ERP right for you?

It's usually a good fit if you:

• Have standard trading, distribution, light manufacturing or service operations
• Want to own your data and hosting
• Have, or can hire, some technical capability
• Prefer spending on implementation over licences

It's usually a poor fit if you:

• Have no technical support and don't want a partner
• Need certified compliance features that only a commercial vendor provides
• Expect the software to work fully without any setup

Where to go next

Compare the main options in best open-source ERP systems compared. If you're leaning towards Odoo, read Odoo Community vs Enterprise. And if you'd like help deciding, our ERP consulting service is built for exactly this question.