Lago
Usage-based billing and metering
Lago meters usage events and turns them into invoices, with plans, coupons and payment provider connections. It is an alternative to Stripe Billing for products with usage-based pricing, and is AGPL.
More in Business ops
Documenso
Business ops
Document signing you can self-host
ERPNext
Business ops
ERP for small and mid-size companies
Formbricks
Business ops
Surveys and in-product feedback
Odoo
Business ops
Modular business apps for sales, accounting and inventory
OpenProject
Business ops
Project management for classic and agile teams
SuiteCRM
Business ops
Long-running open source CRM