Open-source licenses, plain language

“Free” never means “do whatever”. Every tool has a license. Short guide.

Three colours I use

• Green (MIT, Apache-2.0, BSD) — use commercially, modify, even sell. Keep attribution.
• Yellow (GPL, AGPL, LGPL, MPL) — you may run it. If you distribute modified code, share your changes under the same terms. AGPL also “sees” through the network. Practical rule: use as a service for yourself; don’t embed in a product you sell without advice.
• Red (no license) — all rights reserved. You can read and learn. Don’t copy.

For a small business

1. MIT PMS — run it for your units, change the logo, even operate it for other hosts.
2. AGPL tool (e.g. FreeScout) — self-host and use. Don’t ship its code inside a paid product.
3. Scrapers — license may be MIT; the site ToS is often the real risk.

Quick chooser

You want to…	Look for
Run it inside your company	any green license
Embed in a product for customers	MIT / Apache
Modify and keep changes private (as SaaS)	careful with AGPL
Learn from the code only	anything, including red

When unsure: read LICENSE, then choosealicense.com.