[the_laka]

I've used readme.com with mixed results. TBH, wouldn't recommend. It's easy to setup but the cost of maintaining and updating it becomes more and more with every new endpoint. And if you've got a lot of them, it also tends to slow down.

docusaurus.io is the next tool on my list to try out, it looks promising. I think it's better suited for smaller projects, with a lot of things out of the box. I haven't seen an API company using it yet though.

Station is something I've used in the past, because I was working for Nexmo at the time. The team at Nexmo / Vonage won a few awards because of it for the best Developer Portal a few years back. It's open source now, and the cost to setup might be higher than the other two, but a lot of the design decisions make sense for an API portal. It's also super fast once deployed, and that helps a lot with developer perception. https://github.com/Nexmo/station