Vrite - Open-source, headless CMS for technical content.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.
code_doc - Hosted documentation and artifacts server
Docsie - Docsie makes it easy to create and maintain your website documentation, without having to deploy it...
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
ReadMe - A collaborative developer hub for your API or code.