Open-source alternatives to Netlify

Coolify is open source: free to download and run on your own server. Netlify costs from $9 a month, with a free plan.

Coolify

Open source (Apache-2.0) · Self-hosted platform to deploy apps, an alternative to Vercel and Netlify

Coolify deploys applications, databases and services on your own servers over SSH, with Git push deploys and pull-request previews.

Free to download and run on your own server under the Apache-2.0 licence; you pay only for your hosting. A hosted Coolify Cloud is also offered.

Free to use, not free to run. The licence costs nothing, but self-hosting needs a server (often $5 to $40 a month) and someone to install updates and keep backups.
Open core means the main product is open source but some features, usually for larger teams, need a paid licence.
Hosted versions exist for many of these, run by the makers. They cost money but save the upkeep, and you can still move to your own server later.
Licences differ. MIT and Apache allow almost anything. GPL and AGPL require you to share changes you make to the code; for normal business use, that rarely matters.