List of free knowledge-base stuff for developerππ½
If you're looking for all programming tools around knowledge-base (not just free). Check this page List of knowledge-base Programming Tools

Free forever Live Chat Ticketing Knowledge Base Chat Pages Team Chat

2 Seats (Admin)
For personal websites and anyone who wants a basic chat to communicate with visitors.
Livechat, Team Inbox, Mobile Apps, Notification

Gitbook
GitBook helps you publish beautiful docs and centralize your teams' knowledge. From technical teams to the whole company.
Tag: knowledge-base, note-taking, docs
Unlimited Public Spaces Unlimited Private Spaces Advanced Editing Capabilities Publish And Customise Your Docs Custom Domains
Notion
A new tool that blends your everyday work apps into one. It's the all-in-one workspace for you and your team.
Tag: productivity, note-taking, knowledge-base
Free for individuals Unlimited pages & blocks Share with 5 guests Sync across devices APIBETA
AFFiNE - All In One Workos
Affine is the next-generation collaborative knowledge base for professionals.
Tag: productivity, note-taking, knowledge-base

Logseq
Logseq is a joyful, open-source outliner that works on top of local plain-text Markdown and Org-mode files. Use it to write, organize and share your thoughts, keep your to-do list, and build your own digital garden.
Tag: knowledge-base