About Undertale Yellow Online
undertaleyellow.org is an unofficial fan site where you can play Undertale Yellow in the browser and read player-focused guides about it.
How we write pages
Facts come from Team Undertale Yellow's own Game Jolt page, FAQ and patch notes, from Wikipedia's article on the game and from the community-run Undertale Yellow Wiki. We also play the browser version ourselves to check controls, loading and saves. When something can't be confirmed by a source, we leave it out.
The browser version
The game on our homepage is an unofficial web port of the official Windows release, version 1.3.1. We did not change the game's content. The official, supported release is the free Windows download on Game Jolt — please get it there and follow the team for news.
Credits
Undertale Yellow is made by Team Undertale Yellow, directed by MasterSwordRemix. UNDERTALE and its characters belong to Toby Fox. Screenshots, key art and character art on this site come from the official Game Jolt page; the opening-scene screenshots were captured from the browser version; the pixel-art illustrations on our guide, download and 404 pages are original fan illustrations made for this site.
Official sources
- Official Game Jolt page: Undertale Yellow by Team Undertale Yellow
- Team UTY: Version 1.1 Out Now! (Patch Notes), Dec 14, 2023
- Team UTY: Version 1.2 (Patch Notes), Jul 13, 2025
- Team UTY: Version 1.3 (Patch Notes) incl. 1.3.1 hotfix, Jul 30, 2026
- Wikipedia: Undertale Yellow
- Undertale Yellow Wiki (Fandom)
- Undertale Yellow on X/Twitter
- UNDERTALE by Toby Fox (official site)
Contact
The developers or anyone with a correction can email hello@undertaleyellow.org. Removal requests from Team Undertale Yellow or Toby Fox will be honoured.