Open source alternatives to SugarCRM

By GitHub stars it is Odoo, with 55,775 stars and a commit on 14 Nov. Choose Odoo when you want CRM and ERP from one vendor instead of joining a CRM to a separate ERP. Next come Krayin CRM (24,150 stars) and EspoCRM (3,610 stars).

Yes. The code of all 3 is public under LGPL 3.0, MIT or AGPL 3.0, so you can use them with no licence fee. Running one yourself costs the server and your time to look after it, and some makers also sell a hosted plan.

Start from the job you use SugarCRM for. Choose EspoCRM when you want accounts, cases, campaigns and a customer portal on your own PHP server without a per-user licence. Choose Krayin CRM when you need a B2B lead and deal pipeline that PHP developers can extend, without a licence fee per user.

All 3: Odoo, Krayin CRM and EspoCRM. Each tool's page says what it needs to run.

All 3 we track had a commit in the last 30 days, among them Odoo, Krayin CRM and EspoCRM. A recent commit shows the project is kept up, not that it will stay that way.

LGPL 3.0 (1), MIT (1), AGPL 3.0 (1). MIT, BSD and Apache let you change and reuse the code freely. GPL and AGPL ask you to share your changes under the same licence when you give the software to others, and AGPL also counts letting people use it over a network.

The hosting. SugarCRM's maker runs the servers for you; with an open source tool the updates, backups, security fixes and support are yours, unless you take the maker's hosted plan. Features differ too, so check what each one imports and exports before you move your data.