License

Last updated: 1 July 2026

ESMS uses a two-tier model: the app is free to use for individuals, and the source code is published on GitHub. Business or commercial use requires a separate commercial license.

What AGPL-3.0 means in practice: anyone can view, use, and modify the ESMS source code — including commercially — but if they modify it and run it as a network service, they must make their modified source available too. It doesn't by itself stop a company from using ESMS commercially; it stops them from taking the code closed-source. That's why business deployments still go through a separate commercial arrangement (see below), which also covers support and terms the AGPL doesn't address. The LICENSE file in the GitHub repository is the legally authoritative version — this page is a plain-language summary.

1. The app (compiled APK)

The compiled Android application available on the Download page is free to install and use for personal, non-commercial purposes. See the Terms of Use for the full terms that apply to using the app itself.

2. The source code

Where we publish the ESMS source code on GitHub, it is licensed under GNU Affero General Public License v3.0 (AGPL-3.0). The full legal text is in the LICENSE file in the repository — github.com/YOUR-USERNAME/YOUR-REPO. That file governs anything not covered here.

3. Personal vs. commercial use

Personal use — installing and using ESMS for yourself, at no cost, is always free, regardless of which source license is chosen above.
Commercial / business use — deploying ESMS across an organization, bundling it into a paid product, or otherwise using it for commercial advantage requires reaching out via the enterprise licensing form to arrange terms.

4. A quick note on common licenses

If you're deciding which license to publish the code under, here's the plain-language difference between the options most projects consider:

MIT / Apache 2.0 / BSD — permissive. Anyone can reuse, modify, or resell the code, including commercially, with minimal restrictions. Simple and widely recognized, but doesn't by itself enforce the "commercial use needs a license" model described above — that would need to be handled separately, contractually.
GPL v3 / AGPL v3 — copyleft. Anyone can use the code, including commercially, but any derivative work must also be released under the same license and its source made available. AGPL extends this to software run over a network. Doesn't block commercial use, but does prevent someone from taking the code closed-source.
Source-available licenses (e.g. PolyForm Noncommercial, Business Source License) — the code is publicly visible, but commercial use is restricted or requires a separate agreement, matching the model described on this page directly.

5. Contributions

If the GitHub repository accepts external contributions, contributors agree that their contributions are licensed under the same terms as the project (see the repository's CONTRIBUTING file, if present).

6. Trademarks

The ESMS name and logo are not covered by the source code license. They may not be used to name or promote a derivative product without permission.

7. Questions

For anything about licensing — personal, commercial, or contribution-related — reach us through the contact form or at contact@cactusprotocol.com.