Self-hosting is the practice of running an application on infrastructure you control — usually a virtual private server, a home lab, or a corporate data center — rather than paying a SaaS vendor to run it for you. The operator owns the data, the uptime, and the upgrade schedule, and is responsible for backups, monitoring, and security patching. Most modern self-hostable applications ship as Docker images and can be run with a single docker-compose.yml on a cheap VPS.

In a self-hosting context

Almost every paid SaaS in this directory has at least one open-source self-hostable replacement. Mattermost replaces Slack, Nextcloud replaces Google Drive, Gitea replaces hosted GitHub, Plausible Analytics replaces Google Analytics. The trade-off is operational labor: you swap a fixed monthly bill for a few hours a year of patching and backup verification, in exchange for data sovereignty and no per-seat pricing. Browse /tool/ for every OSS tool in scope, or pick a SaaS like Slack or Google Drive to see specific replacements.