If by “alternative to WHMCS” you mean a free/self-hosted billing system for a web-hosting business, there are several possibilities, but there is an important tradeoff: the more WHMCS-like automation and integrations you require, the harder it is to find a completely free replacement that is equally mature.
One option worth examining is BoxBilling. It is open-source and was designed specifically for hosting-company billing. It includes features such as:
- client accounts,
- invoicing,
- recurring billing,
- multiple currencies,
- payment-gateway integration,
- hosting/service management, and
- extensibility through modules.
That makes it considerably closer to WHMCS than a generic invoicing application.
Another open-source project is FOSSBilling, although for a question asked in 2019 specifically, BoxBilling would have been the relevant project at that time.
If you only need invoicing rather than automated hosting provisioning, there are also general-purpose open-source systems such as Invoice Ninja. However, these should not be considered direct WHMCS replacements because WHMCS combines billing with hosting-specific functions such as provisioning, domain management, support, and account automation.
I would therefore make a checklist before choosing:
billing + recurring invoices + payment gateways + hosting provisioning + domain registrar integration + support/tickets + security updates + active development.
A product can have a long feature list and still be a poor choice if it is no longer actively maintained. For billing software in particular, security and maintenance should rank above having the maximum possible number of features.
So if free and self-hosted are absolute requirements, I would start by investigating BoxBilling and similar open-source projects. If this will run an important commercial hosting business, however, I would not reject WHMCS or another paid product solely because it costs money—the reliability, security updates, integrations, and support may easily justify the licensing expense.
