· 2 min read

Open Source is free until it isn't.

Open source is not the opposite of paying for software. Four business models hide behind one label: foundation-run, open core, source-available, and support-funded. Buy a stack and you inherit all of them. What breaks on day two, and the four questions to ask before you sign.

Open Source is free until it isn't.
Open Source is free until it isn't. Whether a free edition stays free is decided by the business model, not just the licence.

Whether a free edition stays free is decided by the business model, not just the licence.

Open source is not the opposite of paying for software. That mistake will catch you off-guard down the road.

Most people file software into two boxes: proprietary, which you pay for, and open source, which you don't. Neither box is real. I have taken these apart for years, and the licence alone never settles it.

Start with what people picture: LibreOffice, the desktop office suite, run by a foundation with nothing to sell. Everything it has, everyone gets, permanently. Much of the internet runs on this, built by foundations and unpaid volunteers. But you cannot assume it of every product.

Things change when there is a company behind it. It needs revenue and cannot charge for code anyone may copy legally. So it sells what a copy does not give you. The three most common you will encounter:

Features. Some are held out of the free edition and sold back: open core. Odoo is an all-in-one business suite: sales, stock, invoicing, HR. Used by hundreds of thousands of companies. The licence is open source. The free edition sends invoices. Accounting is in the paid edition. A free edition isn't a smaller version; it is the product without the parts that make it work at scale.

Permission. Nothing is missing, but the licence changes. Pimcore, which stores a retailer's product data, is free until you pass five million euros in revenue. Then a commercial contract is mandatory, with no open-source path out. Licences like this are called source-available. Growth is the trigger.

Service. Zammad, a help desk platform, withholds nothing from its self-hosted version: every feature, unlimited users, single sign-on. The licence stays free. Support starts near three thousand euros a year.

All three assume one product from one company. What happens when it is not?

openDesk, Germany's state-owned answer to Microsoft 365, is not one single product. It is a stack of a dozen existing ones, most with their own vendor and model. openDesk's builders gated nothing, yet the free edition cannot add or remove accounts automatically as staff come and go. Those gates belong to the suppliers underneath. Buy a stack, inherit every model in it.

What hurts is not asking upfront. Rollouts often start as a pilot on the free edition. The constraint arrives on day two, at the scale you were aiming for, after you migrated, trained and spent. And a paid edition means one supplier, exactly the dependency you were trying to leave.

Against a proprietary suite they all still win. There you get no free edition, no source, no exit at any price. Four questions get you the rest:

The licence rarely gives you the full picture. The business model does. It is why I built OpenTechHub, to answer these while there is still a choice.

Some of what you already run might be one of these four. Which one, and when did you find out?

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