YPR File

What are YPR files and how to open them

Are you having problems opening a YPR file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your YPR files.

What is a YPR file?

A .YPR file is a BYOB Project file.

BYOB Project format is the file type used by the visual programming environment called BYOB (Build Your Own Blocks). Files with the .YPR extension store entire project files including all blocks, scripts, sprites, resources, and layout. If you are working on a program in BYOB and save the project, it becomes a .YPR file so you can later open it and continue editing.

BYOB was originally an extension of Scratch developed by MIT's Lifelong Kindergarten Group. .YPR files let users build custom blocks, manipulate lists, use continuations, and more advanced structures not present in older Scratch versions. These files enable complete saving and loading of a project's logic, its visual block connections, properties like author, history, thumbnail, language, platform, and environment metadata.

.YPR files are written by BYOB (also developed later under the name Snap). The application writes the file to disk in a binary format, which includes strings like SCRATCH-VERSION, OS-VERSION, PLATFORM, AUTHOR, LANGUAGE, HISTORY, THUMBNAIL among its internal fields. The beginning of a .YPR file starts with a signature such as BloxExpV01 at byte offset 0 and ObjS.Stch at offset 14 to identify the format unambiguously.

How to open YPR files

We have identified one YPR opener that is compatible with this specific type of YPR file.

Programs that open BYOB Project files

Last updated: August 14, 2026

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about YPR file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.