Question: I'm looking for a text-based RPG platform that allows players to create and customize their own adventures.

For a text-based RPG foundation that lets you build and customize your own games, AI Adventure is an excellent choice. This open-source foundation uses cutting-edge AI to create a new style of storytelling and offers unlimited customization options, a powerful adventure editor, and built-in services like Stripe for payments and Clerk for authentication. You can explore and chat with characters, find community-created adventures, and help with the project on GitHub.

Another great option is AI Dungeon, which offers an infinitely generated text adventure system based on deep learning. It combines AI-generated content with interactivity, letting you explore and chat with an ever-expanding world with commands like 'start,' 'help,' 'quit,' 'save,' and 'load.' It's great for text adventure fans and curious people who want to see what AI-generated content is all about, and it's a fun, dynamic way to play.

Saga is also worth a look. It marries the best of old-school RPGs with modern technology, letting you chat with AI-powered characters and play through customizable storytelling. With features like AI-generated illustrations, free-form writing and a community forum for idea sharing, Saga offers a flexible and creative gaming experience on multiple platforms.