import { Card, Cards } from 'fumadocs-ui/components/card';

The Format SDK is the high-level layer of datamark. It turns Markdown documents into typed objects — and back again — through reusable, self-testing format definitions.

A **format** is a typed contract: you define a schema, a `parse` function that walks the AST using the [Parse SDK](/docs/parse), and optionally a `stringify` function for round-trip serialization using builder primitives from `datamark/stringify`. Add inline `examples` and your format becomes self-documenting and self-testing.

<Cards>
  <Card title="datamark()" description="The format factory — typed config, parse, stringify, test, docs" href="/docs/template/datamark-function" />

  <Card title="Frontmatter" description="Reading, validating, and typing frontmatter with schemas" href="/docs/template/frontmatter" />

  <Card title="Parsing Patterns" description="Navigate the AST, extract data, map Markdown to objects" href="/docs/template/parsing" />

  <Card title="Stringify" description="Serialize back to Markdown with builder primitives from datamark/stringify" href="/docs/template/stringify" />

  <Card title="Testing" description="Inline examples, self-testing formats, and CI integration" href="/docs/template/testing" />
</Cards>

What the Format SDK provides [#what-the-format-sdk-provides]

| Capability                   | Description                                                                                 |
| ---------------------------- | ------------------------------------------------------------------------------------------- |
| **Typed frontmatter**        | `frontmatterSchema` validates and types `doc.frontmatter` before your `parse` function runs |
| **Output validation**        | `schema` validates the return value of `parse()` automatically                              |
| **Round-trip serialization** | `stringify` turns typed data back into Markdown via `datamark/stringify`                    |
| **Self-testing**             | `examples` are validated by `.test()` — add them once, test forever                         |
| **Builder primitives**       | `heading()`, `list()`, `codeBlock()`, `frontmatter()` and more from `datamark/stringify`    |
| **Standard Schema support**  | Works with Zod, Valibot, ArkType, TypeBox, and any Standard Schema v1 validator             |

How the layers fit together [#how-the-layers-fit-together]

```
datamark/stringify  →  heading(), list(), codeBlock(), frontmatter() …
        ↑
   Format SDK      →  datamark({ schema, parse, stringify, examples })
        ↑
    Parse SDK      →  parse(), findAll(), textContent(), isCodeBlock() …
        ↑
    marked + yaml  →  Markdown lexer + YAML parser
```

The Format SDK is built on top of the Parse SDK. Every `parse` function receives a `Document` from the Parse SDK and uses its utilities (`findAll`, `textContent`, `isCodeBlock`, etc.) to extract data. Every `stringify` function uses `datamark/stringify` primitives to reconstruct Markdown cleanly.

For raw AST manipulation without schemas or serialization, use the [Parse SDK](/docs/parse) directly.