How does the AGPL work?
The AGPL is copyleft: if you distribute the software or a modified version, you must release your changes under the same license and provide the corresponding source. The GPL already does this. What the AGPL adds is a trigger for network use — the case where users reach the software as a hosted service and no copy is ever handed to them. That single addition is why projects building open-source marketing automation and other server software reach for it.
What does the network-use clause (section 13) require?
Section 13 says that if you modify AGPL software and let users interact with your modified version remotely over a network, you must prominently offer those users the corresponding source of your version, downloadable at no charge. It applies to your modifications — running an unmodified copy as a service does not, by itself, oblige you to publish anything new. The obligation runs to the people using the network service, not only to whoever you hand a binary to.
AGPL vs GPL vs MIT: how do they differ?
| License | Copyleft strength | Network-use trigger | Example project |
|---|---|---|---|
| MIT | None — permissive | No | Novu, Dittofeed |
| GPLv3 | Strong, on distribution | No | Mautic |
| AGPL-3.0 | Strong, on distribution and network use | Yes (section 13) | listmonk, fromHello |
Why it matters for a small team
For a two- or three-person team, the license is a strategic choice, not paperwork. The AGPL lets you publish your code and still discourage a larger competitor from running your exact service closed-source, because they would owe their users the source of any changes. It also reassures the buyer who wants to inspect and self-host: the source is a right, not a favor. Weigh it against a permissive license as you read open source versus SaaS marketing tools — the trade-off is reach versus reciprocity. This describes how the license is written, not legal advice.