Playground ​

Try a feature without installing anything. Pick an example, change its JSON, and press Run preview: the feature is placed into a small bench world right here in your browser, by the same engine the VS Code extension and the featurelab command use, and drawn in the same 3D view.

• The editor holds one feature file. If it places other features by identifier — a scatter's places_feature, say — and those are examples on this site too, they are loaded with it and listed under the editor. Rename one and it is unresolved, exactly as it would be in your pack.
• The sidebar is the extension's. Change the environment preset, the bench size or the seed there and the preview runs again. The Diagnostics section lists everything the engine had to say about the run; when nothing is placed, start there and then at When the preview shows nothing.
• Nothing you type leaves your browser. The engine is a download of about 9 MB, fetched once while you read and kept by your browser for your next visit.

It runs one file and the examples it names. Your own pack — its blocks, biomes, structure files and the rest of its features — needs the extension or the CLI, and blocks here are drawn in flat colours rather than with their textures.