What is an ATLAS file?
An .ATLAS file is a data file used in game development and 2D animation. It contains text or JSON data. This data maps the coordinates of smaller images inside a larger image file. Developers call this larger image a sprite sheet or a texture atlas. An .ATLAS file does not contain image graphics. It only contains the text information needed to find individual sprites within an associated image, such as a .PNG file.
Many popular game tools and frameworks use .ATLAS files. Common examples include Spine for 2D animation, TexturePacker for sprite sheet generation, and the libGDX game framework. The exact structure of the text inside the file depends on the software that created it.
How to open ATLAS files?
Because most .ATLAS files store data in plain text or JSON format, you can open them with standard text editors. You can use Notepad++ on Windows, Apple TextEdit on macOS, or cross-platform code editors like Visual Studio Code. To use the file in a game, you must import the .ATLAS file and its matching image file into your game engine or animation tool.
If you do not know which software created your file, viewer.online/atlas analyzes .ATLAS files to identify their exact format and creator software, shows which programs can open the file, and usually previews it.
Best practices and troubleshooting
Always keep your .ATLAS file in the same folder as its target image file. If you move or rename the image file, the game engine will fail to read the texture atlas. If your file does not load, open it in a text editor to check the referenced image file name inside the code.
If you need to change the file format for a different game engine, you can often convert the text data. We recommend checking convert.guru to transform your file into other sensible target formats, such as standard JSON or XML structures.
Summary
An .ATLAS file is a text-based map for game textures and 2D animations. Because .ATLAS files use the known JSON format, viewer.online/atlas can safely open and display them online, eliminating compatibility problems.