Delivery & CI · Updated 2026-09-17
Open source
Software whose source code is published under a licence that permits reading, modifying and redistributing it — which is a licensing property, not a deployment one.
Also called: OSS
What it is
An open-source tool publishes its source under a licence granting rights to use, study, modify and share it. For a code review tool, the most interesting consequence is that you can read how the review prompt is built and what leaves your network.
The licence families that matter here
- Permissive (MIT, Apache 2.0, BSD): use it almost however you like, including inside a commercial product.
- Copyleft (GPL, AGPL): modifications must be published under the same terms. AGPL extends that to software offered over a network, which is why it appears often in this category.
- Dual-licensed: an open core with commercial-only components, typically the enterprise features. Common, and worth reading carefully — “open source” on the homepage can mean “some of it”.
What open source does not guarantee
It does not mean free to run: you still pay for inference and infrastructure. It does not mean self-hostable, though the two often coincide. It does not mean maintained — check commit recency and issue response before depending on it. And it does not mean your code stays local; an open-source tool can still call a vendor API on every review.
Common mistakes
- Reading the badge and not the licence file.
- Assuming an open-source tool needs no vendor relationship, then discovering the hosted version is where the features are.
- Adopting an unmaintained project because the README looked current.