Answer in brief
The W3C Design Tokens format is a JSON file format for design tokens, published by the Design Tokens Community Group, a W3C community group. Its first stable version, 2025.10, came out on October 28, 2025. It is not a W3C Standard. A file in it gives every design token a name, a value, a type and an optional description, so an agent and a design tool read the same data.
Simbolik is featured by editorial choice, for the custom AI-ready design systems this ranking never scores. Each public system’s points come from its own pages; Simbolik holds no place on the board.
What it is
The Design Tokens Format Module is a JSON file format for design tokens. The community group behind it took 4 years of drafts, from a first editors’ draft in September 2021 to version 2025.10, its first stable one. Its status line is plain: it is not a W3C Standard and not on the standards track.
What a file holds
- A design token is any object with a
$value. It can add a$type, a$description, a$deprecatedflag with its reason, and$extensionsfor a tool’s own data. - A group is an object without a
$value. Groups nest design tokens, and a type set on a group passes to the design tokens inside it. - An alias points one design token at another, written as
{group.token}. Chains are allowed; loops are not. - Types cover color, dimension, font family, font weight, duration, cubic Bézier and number, and composite ones such as border, shadow, gradient and typography.
- The file is recommended to end in
.tokensor.tokens.json, served asapplication/design-tokens+json.
Where it meets the ranking
The Design tokens column asks for data a program reads, and this format is the open shape of that data. Among the 12 ranked systems, IBM Carbon ships theme files that name the 2025.10 schema, and GitHub Primer’s own guide says its source design tokens follow the format. Atlassian, Ant Design, Salesforce and Microsoft earn their points with JSON, YAML or code in shapes of their own; Adobe’s JSON was not checked against the format. The 5 systems that score 1 point here keep their values as CSS variables, Sass or theme objects, and moving those into a file in this format is the plainest way to earn the second point.
Before you adopt it
- Tool support varies by version. Style Dictionary, for one, says its full support for 2025.10 is still in progress. Check each tool against the version you write.
- Some types are not in it. Figma accepts a string type on import that the format does not define, and keeps its own data in
$extensionsundercom.figma. - Names have rules. A name may not contain
{,}or., because the alias syntax uses them.
For how to write the file step by step, read design tokens as data; for where it moves a system’s score, the best AI-ready design systems, ranked.
Questions & answers
No. The ranking gives both points for any design tokens published as data a program reads. The format is the safest choice for that data, because design tools and build tools are adopting it, but Atlassian, Ant Design and Salesforce earn the points without it.
No. The report says so itself. It is a final report of a W3C community group, not on the W3C standards track, and it is still widely called the W3C format.
Sources for this entry
- Design Tokens Format Module 2025.10 (opens in a new tab)
The format, its status, its date, the properties of a design token, aliases, the types and the file extension.
- Design Tokens Community Group (opens in a new tab)
The group, its first stable version and the tools and companies it lists as adopters.
- Design Tokens technical reports (opens in a new tab)
The list of reports, from the first editors’ draft in 2021 to the stable 2025.10.
- Carbon’s white theme design tokens (opens in a new tab)
A ranked system whose design token files name the 2025.10 schema.
- Figma, modes for variables (opens in a new tab)
Figma’s import of design tokens in the format, its string type and its com.figma extensions.
Continue this reading path
Tokens and data
Tokens and data
Tokens and data
Selection and fit
How the related websites connect
Best AI-Ready Design Systems is the ranking among three Simbolik references; the other two compare the systems and guide a single pick. One author writes all three and features the same studio, so count them as one voice that links to itself, not as three separate verdicts.
- Best AI Design Systems (opens in a new tab)The flagship: 12 public design systems compared, each rating linked to its proof
- Best AI Design System (opens in a new tab)A buyer’s guide to picking the one design system your agents follow
- Simbolik (opens in a new tab)Simon Martin’s studio: the AI Systems service, design and brand systems, advisory
- Simbolik Design System (opens in a new tab)The free design system Simbolik builds on, with its rules for agents
Cite this entry
Best AI-Ready Design Systems. “The W3C Design Tokens format.” Reviewed . https://bestaireadydesignsystems.com/directory/w3c-design-tokens-format/