Documentation for Wolfram Language:<p><a href="https://reference.wolfram.com/language/" rel="nofollow">https://reference.wolfram.com/language/</a><p>It's detailed, complete, shows many examples for commom use cases, 'neat' examples showing what's possible, and lists down possible issues. I do see certain documentation quality issues sometimes.<p>The documentation itself is done using the features of Wolfram Language, so the examples can be run inline (depending on the platform).
I haven't done serious frontend web dev for a while, but MDN was consistently excellent a few years back.<p><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript" rel="nofollow">https://developer.mozilla.org/en-US/docs/Web/JavaScript</a>
PHP docs are an underrated gem. They get several things right:<p>1. Individual pages for each function.<p>2. Clear examples for common usecases.<p>3. Explicit documentation for input and return types.<p>4. The quick search is amazing - it prioritizes library reference over other pages.<p>5. Clean and useful references to related methods.<p>The user submitted notes were a big positive a decade ago - they highlighted common gotchas, workarounds, and surprising alternatives, but have gotten dated over time (kinda like SO answers). But the voting mechanism attempts to keep them in check.<p>Compare <a href="https://www.php.net/manual/en/function.str-contains.php" rel="nofollow">https://www.php.net/manual/en/function.str-contains.php</a> to the tiny one paragram you get at <a href="https://docs.python.org/3/library/stdtypes.html#str.find" rel="nofollow">https://docs.python.org/3/library/stdtypes.html#str.find</a> (which then redirects most users to a far more confusing explanation about the in operator <a href="https://docs.python.org/3/reference/expressions.html#membership-test-operations" rel="nofollow">https://docs.python.org/3/reference/expressions.html#members...</a>
Arch (a Linux distribution) has excellent documentation that can be reused in other distros. Not the "how to install part" but rather the "how to configure" one.<p>I usually prefer to read their docs rather than the ones in man pages which are "flat" (all the initiation had the same importance)
I appreciate the HAProxy docs. They're stored as text files in the main code repository, though there are HTML representations.<p>There are three main files:<p><i>Starter Guide</i>: <a href="https://docs.haproxy.org/3.0/intro.html" rel="nofollow">https://docs.haproxy.org/3.0/intro.html</a><p><i>Configuration Manual</i>: <a href="https://docs.haproxy.org/3.0/configuration.html" rel="nofollow">https://docs.haproxy.org/3.0/configuration.html</a><p><i>Management Guide</i>: <a href="https://docs.haproxy.org/3.0/management.html" rel="nofollow">https://docs.haproxy.org/3.0/management.html</a><p>Having all the similar docs together in the same file (all config options, for example) is refreshingly simple.
Every time "documentation" is mentioned, it would help to specify which quadrant this is about: <a href="https://docs.divio.com/documentation-system/" rel="nofollow">https://docs.divio.com/documentation-system/</a><p>I see answers here that are oriented towards completely different parts.
The online documentation for Lotus (later IBM, later HCL) Notes/Domino is excellent. It's not purely a "site" because the documentation is a Notes database itself, but it is also available on the public Internet [1], so I think it counts.<p>For open source projects, Django [2] is pretty close to the gold standard.<p>[1] <a href="https://help.hcl-software.com/dom_designer/14.0.0/index.html" rel="nofollow">https://help.hcl-software.com/dom_designer/14.0.0/index.html</a><p>[2] <a href="https://docs.djangoproject.com/en/dev/" rel="nofollow">https://docs.djangoproject.com/en/dev/</a>
PHP Docs are pretty good as already mentioned.<p>I personally love the Documentation for Kirby CMS:<p><a href="https://getkirby.com/docs/guide" rel="nofollow">https://getkirby.com/docs/guide</a><p><a href="https://getkirby.com/docs/reference" rel="nofollow">https://getkirby.com/docs/reference</a><p><a href="https://getkirby.com/docs/cookbook" rel="nofollow">https://getkirby.com/docs/cookbook</a>
For a product: Delphi 2. I don't think I ever saw a better offline documentation which is so self-contained<p>For a project: MDN, they refactored the Web's JS documentation
All of raspberry pi’s SDK documentation and data sheets for the pico (rp2040) are amazing. Perfect material to build an embedded engineering course around.
Vim - <a href="https://vimdoc.sourceforge.net/htmldoc/usr_toc.html" rel="nofollow">https://vimdoc.sourceforge.net/htmldoc/usr_toc.html</a><p>Stripe<p>Django<p>Hubspot<p>Mercurial with comments <a href="https://hgbook.red-bean.com/read/a-tour-of-mercurial-the-basics.html" rel="nofollow">https://hgbook.red-bean.com/read/a-tour-of-mercurial-the-bas...</a>
Generally speaking, Elixir. Documentation is written in the language itself, it is easy to create, and is very well written. As the authors themselves are the first users of the documentation facilities, they are very well done and maintained.<p>This in turn means that the structure and style is shared by many libs in the ecosystem, and everything is natively cross-referenced.
As a general rule (for established libraries at least), the docs for rust crates stored on <a href="https://docs.rs" rel="nofollow">https://docs.rs</a> are pretty good. This comes from having docs being built-in to the tooling, so it's really easy to deliver docs in a consistent format.
This is a bit of an unusual choice, but I recently was trying to use Webflow, and its videos are both highly informative and funny! Engineers often thumb their noses at videos, but they really show how to do it well:<p><a href="https://university.webflow.com/videos" rel="nofollow">https://university.webflow.com/videos</a>
I've seen a few sites train LLMs / use RAG on their online docs. When I used it, it was very useful in terms of search and synthesis. imo it'd be nice if projects release a current model trained on their documentation and code.
BuildBuddy<p><a href="https://www.buildbuddy.io/docs/introduction/">https://www.buildbuddy.io/docs/introduction/</a><p>I don't think I ever had a case that wasn't covered in the docs.