A2UI Express Converter

A2UI Express is a compact syntax Google introduced on October 27, 2026 for describing user interfaces. Instead of writing verbose A2UI JSON directly, a model writes short one-line statements, and a compiler turns them into standard A2UI v1.0 JSON. Google reports it needs up to 3x fewer tokens than direct JSON.

It converts A2UI Express to A2UI v1.0 JSON and back, using the official A2UI Basic Catalog. It also shows character counts, estimated token counts and the reduction between the two forms, and it validates your input and lists every problem with a line number.

Token counts here are estimates only. The page divides the character count by 4, a rough rule of thumb for English text. Real token counts vary by model and by content, so treat the number as a guide for comparing the two formats, not an exact bill.

All 18 components of the A2UI Basic Catalog: Text, Image, Icon, Video, AudioPlayer, Row, Column, List, Card, Tabs, Modal, Divider, Button, TextField, CheckBox, ChoicePicker, Slider and DateTimeInput. Positional arguments map to catalog properties in schema definition order, exactly as the specification requires.

Unknown components, wrong argument counts against the catalog, undefined variable references, duplicate variable ids, invalid identifiers, a missing surface() call or root component, and malformed Event() calls. Problems are listed with line numbers so you can fix them one by one.

No. All conversion and validation runs in your browser on your own device. Nothing is uploaded to any server, and Cubbbix never sees your input.

Custom catalogs are not supported yet: this page uses the official Basic Catalog only. List _template() helpers are passed through as function calls rather than compiled exactly, and function arguments for less common catalog functions should be given as keyword arguments so they map correctly.