diff --git a/apps/v4/content/docs/registry/api-reference.mdx b/apps/v4/content/docs/registry/api-reference.mdx
new file mode 100644
index 0000000000..09ff0fb18d
--- /dev/null
+++ b/apps/v4/content/docs/registry/api-reference.mdx
@@ -0,0 +1,422 @@
+---
+title: API Reference
+description: Programmatic API for working with registries, schemas and presets.
+---
+
+The `shadcn` package exposes a set of programmatic APIs in addition to the CLI.
+You can use these to fetch and resolve registry items, validate registry JSON,
+and build custom tooling on top of the registry.
+
+Each API is available under a dedicated subpath import.
+
+```ts
+import { getRegistryItems } from "shadcn/registry"
+import { registryItemSchema } from "shadcn/schema"
+```
+
+<Callout className="mt-6">
+  The CLI commands themselves are not part of the public API. Only the imports
+  documented below are considered stable.
+</Callout>
+
+## shadcn/registry
+
+Fetch and resolve items from configured registries.
+
+Most functions accept an options object. The two options below are common to all
+of them. In the examples that follow, `config` refers to this optional value —
+omit it to use the built-in registries.
+
+### config
+
+- **Type:** `Partial<Config>`
+- **Default:** built-in registries only
+
+The resolved contents of your `components.json` file. Its `registries` field
+maps a namespace (e.g. `@acme`) to a URL and any authentication headers or
+environment variables required to reach it.
+
+```ts showLineNumbers
+import { getRegistryItems } from "shadcn/registry"
+
+const items = await getRegistryItems(["@acme/login-form"], {
+  config: {
+    registries: {
+      "@acme": "https://acme.com/r/{name}.json",
+    },
+  },
+})
+```
+
+### useCache
+
+- **Type:** `boolean`
+- **Default:** `true`
+
+Registry responses are cached **in memory for the lifetime of the process**,
+keyed by the resolved URL. Because the in-flight promise is cached, concurrent
+requests for the same URL are de-duplicated into a single fetch.
+
+Leave this enabled for one-off scripts and CLI runs. Set it to `false` in
+long-running processes (servers, watchers, the MCP server) where the registry
+can change between requests and you need fresh data each time.
+
+```ts
+const fresh = await getRegistry("@shadcn", { useCache: false })
+```
+
+### getRegistry
+
+Fetch a single registry by name.
+
+```ts showLineNumbers
+import { getRegistry } from "shadcn/registry"
+
+const registry = await getRegistry("@acme", {
+  config, // optional Partial<Config>
+  useCache: true,
+})
+```
+
+### getRegistryItems
+
+Fetch one or more registry items by their qualified names.
+
+```ts showLineNumbers
+import { getRegistryItems } from "shadcn/registry"
+
+const items = await getRegistryItems(["@acme/button", "@acme/card"], {
+  config,
+  useCache: true,
+})
+```
+
+Returns an array of registry items:
+
+```json showLineNumbers
+[
+  {
+    "name": "button",
+    "type": "registry:ui",
+    "dependencies": ["@radix-ui/react-slot"],
+    "files": [
+      {
+        "path": "ui/button.tsx",
+        "type": "registry:ui",
+        "content": "..."
+      }
+    ]
+  }
+]
+```
+
+### resolveRegistryItems
+
+Resolve multiple items together with their registry dependencies, merged into a
+single tree. Unlike [`getRegistryItems`](#getregistryitems), which returns the
+items as a list, this walks each item's `registryDependencies` and flattens
+everything — files, dependencies, CSS variables — into one installable object.
+
+```ts showLineNumbers
+import { resolveRegistryItems } from "shadcn/registry"
+
+const tree = await resolveRegistryItems(
+  ["@acme/button", "@acme/card", "@acme/dialog"],
+  { config }
+)
+```
+
+Returns a single merged tree:
+
+```json showLineNumbers
+{
+  "dependencies": ["@radix-ui/react-slot", "@radix-ui/react-dialog"],
+  "files": [
+    { "path": "ui/button.tsx", "type": "registry:ui", "content": "..." },
+    { "path": "ui/card.tsx", "type": "registry:ui", "content": "..." },
+    { "path": "ui/dialog.tsx", "type": "registry:ui", "content": "..." }
+  ],
+  "cssVars": {
+    "theme": {
+      "font-heading": "Poppins, sans-serif"
+    },
+    "light": {
+      "brand": "oklch(0.205 0.015 18)"
+    },
+    "dark": {
+      "brand": "oklch(0.205 0.015 18)"
+    }
+  },
+  "docs": ""
+}
+```
+
+### getRegistries
+
+Fetch the registry directory.
+
+```ts showLineNumbers
+import { getRegistries } from "shadcn/registry"
+
+const registries = await getRegistries({ useCache: true })
+```
+
+Returns an array of registry entries:
+
+```json
+[
+  {
+    "name": "@shadcn",
+    "url": "https://ui.shadcn.com/r/{name}.json",
+    "homepage": "https://ui.shadcn.com"
+  }
+]
+```
+
+### searchRegistries
+
+Search across one or more registries with fuzzy matching.
+
+```ts showLineNumbers
+import { searchRegistries } from "shadcn/registry"
+
+const results = await searchRegistries(["@shadcn"], {
+  query: "button",
+  types: ["registry:component"],
+  limit: 100,
+  offset: 0,
+  config,
+  continueOnError: true, // skip (don't throw on) registries that fail to load
+})
+```
+
+Returns matching items wrapped in pagination metadata:
+
+```json
+{
+  "pagination": { "total": 1, "offset": 0, "limit": 100, "hasMore": false },
+  "items": [
+    {
+      "name": "button",
+      "type": "registry:ui",
+      "description": "A button component.",
+      "registry": "@shadcn",
+      "addCommandArgument": "@shadcn/button"
+    }
+  ]
+}
+```
+
+### loadRegistry
+
+Read and resolve a local `registry.json` file from disk, following any
+`include` references, and return the registry catalog.
+
+```ts showLineNumbers
+import { loadRegistry } from "shadcn/registry"
+
+const catalog = await loadRegistry({
+  cwd: process.cwd(), // defaults to process.cwd()
+  registryFile: "registry.json", // defaults to "registry.json"
+})
+```
+
+The returned catalog lists every item but **omits file contents** — like a
+built `registry.json` index.
+
+<Callout className="mt-6" title="How is this different from getRegistry?">
+  [`getRegistry`](#getregistry) fetches a **remote** registry over the network
+  (by namespace, URL or GitHub address) and expects the served catalog to
+  already be flattened — it rejects catalogs that still use `include`.
+  `loadRegistry` reads a **local** `registry.json` from disk and resolves
+  `include` references itself.
+</Callout>
+
+### loadRegistryItem
+
+Read a single item from a local `registry.json` by name, with its file contents
+read from disk and inlined.
+
+```ts showLineNumbers
+import { loadRegistryItem } from "shadcn/registry"
+
+const item = await loadRegistryItem("login-form", { cwd: process.cwd() })
+```
+
+Returns a fully resolved registry item with file contents:
+
+```json
+{
+  "$schema": "https://ui.shadcn.com/schema/registry-item.json",
+  "name": "login-form",
+  "type": "registry:component",
+  "files": [
+    {
+      "path": "registry/new-york/login-form.tsx",
+      "type": "registry:component",
+      "content": "..."
+    }
+  ]
+}
+```
+
+<Callout className="mt-6" title="How is this different from getRegistryItems?">
+  [`getRegistryItems`](#getregistryitems) resolves items from a **remote**
+  registry over the network. `loadRegistryItem` builds a single item on demand
+  from your **local** source files, reading each file from disk. Use it in a
+  dynamic route that serves `registry-item.json` responses.
+</Callout>
+
+### Errors
+
+All registry functions throw typed errors that extend `RegistryError`. Use the
+`RegistryErrorCode` enum or `instanceof` checks to handle them.
+
+```ts showLineNumbers
+import { RegistryError, RegistryNotFoundError } from "shadcn/registry"
+
+try {
+  await getRegistry("@unknown")
+} catch (error) {
+  if (error instanceof RegistryNotFoundError) {
+    // handle missing registry
+  }
+}
+```
+
+Available error classes:
+
+- `RegistryError`
+- `RegistryNotFoundError`
+- `RegistryUnauthorizedError`
+- `RegistryForbiddenError`
+- `RegistryFetchError`
+- `RegistryNotConfiguredError`
+- `RegistryLocalFileError`
+- `RegistryParseError`
+- `RegistryValidationError`
+- `RegistryItemNotFoundError`
+- `RegistriesIndexParseError`
+- `RegistryMissingEnvironmentVariablesError`
+- `RegistryInvalidNamespaceError`
+
+## shadcn/schema
+
+The Zod schemas used to validate `registry.json`, `registry-item.json` and
+`components.json`. Useful for validating registry data in your own tooling.
+
+```ts
+import { registryItemSchema, registrySchema } from "shadcn/schema"
+
+const result = registryItemSchema.safeParse(json)
+if (!result.success) {
+  console.error(result.error)
+}
+```
+
+Key schemas:
+
+- `registrySchema`
+- `registryItemSchema`
+- `registryItemFileSchema`
+- `registryItemTypeSchema`
+- `registryItemCssVarsSchema`
+- `registryItemTailwindSchema`
+- `registryBaseColorSchema`
+- `configSchema`
+- `presetSchema`
+
+Inferred types are exported alongside them:
+
+- `Registry`
+- `RegistryItem`
+- `RegistryBaseItem`
+- `RegistryFontItem`
+- `Preset`
+- `ConfigJson`
+
+## shadcn/preset
+
+Encode, decode and validate theme presets, plus the preset option constants used
+by the theme editor.
+
+### encodePreset
+
+Encode a `Partial<PresetConfig>` into a short, URL-safe preset code. Any fields
+you omit fall back to `DEFAULT_PRESET_CONFIG`.
+
+```ts showLineNumbers
+import { encodePreset } from "shadcn/preset"
+
+const code = encodePreset({
+  style: "vega",
+  baseColor: "stone",
+  theme: "blue",
+  radius: "large",
+  font: "geist",
+})
+```
+
+Returns a version-prefixed string:
+
+```ts showLineNumbers
+"bJ4FLU0"
+```
+
+### decodePreset
+
+Decode a preset code back into a full `PresetConfig`. Returns `null` if the code
+is missing or invalid.
+
+```ts showLineNumbers
+import { decodePreset } from "shadcn/preset"
+
+const config = decodePreset("bJ4FLU0")
+```
+
+Returns the resolved config (omitted fields are filled with their defaults):
+
+```json
+{
+  "style": "vega",
+  "baseColor": "stone",
+  "theme": "blue",
+  "chartColor": "neutral",
+  "iconLibrary": "lucide",
+  "font": "geist",
+  "fontHeading": "inherit",
+  "radius": "large",
+  "menuAccent": "subtle",
+  "menuColor": "default"
+}
+```
+
+```ts
+decodePreset("not-a-code") // null
+```
+
+### Other exports
+
+Additional functions for validating codes and generating random presets:
+
+- `isPresetCode`
+- `isValidPreset`
+- `generateRandomConfig`
+- `generateRandomPreset`
+- `toBase62`
+- `fromBase62`
+
+Constants:
+
+- `PRESET_BASES`
+- `PRESET_STYLES`
+- `PRESET_BASE_COLORS`
+- `PRESET_THEMES`
+- `PRESET_ICON_LIBRARIES`
+- `PRESET_FONTS`
+- `PRESET_FONT_HEADINGS`
+- `PRESET_RADII`
+- `PRESET_MENU_ACCENTS`
+- `PRESET_MENU_COLORS`
+- `PRESET_CHART_COLORS`
+- `DEFAULT_PRESET_CONFIG`
diff --git a/apps/v4/content/docs/registry/meta.json b/apps/v4/content/docs/registry/meta.json
index b82573fdc8..61a2cac965 100644
--- a/apps/v4/content/docs/registry/meta.json
+++ b/apps/v4/content/docs/registry/meta.json
@@ -10,6 +10,7 @@
     "authentication",
     "mcp",
     "open-in-v0",
+    "api-reference",
     "registry-json",
     "registry-item-json"
   ]