RDoc vs Redocly

RDoc is free software for producing Ruby project documentation as HTML pages and command-line reference output. The `rdoc` command generates documentation, while `ri` displays it. It processes Ruby, C, and RBS source files, plus RDoc markup, Markdown, RD, and TomDoc documents. RBS declarations can describe classes, modules, methods, attributes, and constants, and can add comments or type signatures to matching Ruby source documentation. A local preview server watches source files and refreshes the browser after changes. It uses Ruby’s built-in TCPServer and needs no external gems, but provides neither HTTPS nor HTTP/2 and is intended only for local previews. RDoc reports documentation coverage with `rdoc -C`, or includes parameter names with `rdoc -C1`. Generation can be automated through Rake or the RDoc API. Aliki is the default theme; Darkfish is deprecated. Ruby 3.2.0 or newer is required for the current gem.

Redocly is an API documentation and governance suite for teams creating, maintaining, and monitoring API experiences. Redoc generates reference documentation from OpenAPI definitions, with automatic code samples, mock servers, and interactive testing through Replay. Reunite supports collaborative editing, visual reviews, remote content, and deployment previews with an audit trail; it connects to GitHub, GitLab, Azure DevOps, or Redocly’s native Git solution. The open-source CLI validates, lints, and bundles OpenAPI definitions, while the VS Code extension helps write and maintain them and flags definition errors. Reef provides a searchable internal API catalog with metadata, scorecards, and discovery features. Respect monitors APIs against an OpenAPI specification and can send alerts through Slack or email. Redocly lists web, API, and extension platforms, custom domains, and content analytics. It says data is encrypted in transit and at rest and reports a completed SOC 2 Type II audit. Pro costs $10.00 per seat/month, billed monthly, and includes one project and 100 pages. API docs can be launched for free, and the full suite has a 30-day trial.