Open Source Licence

Open source licences are the terms under which the world's most valuable software is given away — and 'free' has fine print. A handful of licence families determine whether you can use code in your product, whether you must share your own source, and what happens when a free licence changes its mind. Executives sign the consequences even when engineers did the clicking.

What It Is

An open source licence governs use, modification and redistribution of source code. The families that matter commercially: permissive licences (MIT, BSD, Apache) — use freely, including in commercial products, with minimal conditions such as attribution; copyleft licences (GPL family) — derivative works must be released under the same terms, which can obligate disclosure of your own source; and weak copyleft (LGPL, MPL) — copyleft within modified files, linking without obligation. Beyond these sit licence complexities: AGPL (copyleft triggered by network use — the SaaS trap), and dual-licensing models where the owner offers both free and commercial terms, with the free terms sometimes tightened over time to drive paid adoption.

Why It Matters to You

Three executive-relevant realities. First, licence risk is real but manageable with an inventory — organisations that know which components and which licences live in their products can comply cheaply; those that don't discover obligations during due diligence, at the worst possible valuation moment. Second, the ground can move: components you adopted under permissive terms can be re-licensed in ways that affect future versions — the governance answer is a software bill of materials (SBOM) and a policy for which licences your products may contain. Third, using open source well carries obligations of a different kind: dependency maintenance, security patching, and increasingly, contributing back — free software is free like a puppy, not like a beer.

When You'll Meet It

In product due diligence, M&A processes, and any custom development engagement. Ask engineering two questions annually: what open source is in what we ship, and under what licences — an inability to answer is itself the risk.