diff --git a/README.md b/README.md
index 3fa81b4..9d259e3 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,97 @@ let output = p.process('<template>Hi</template>');
 console.log(output);
 ```
 
+## API
+
+### `Preprocessor`
+
+All `content-tag` public API lives on the `Preprocessor` object.
+
+### `Preprocessor.process(src: string, filename?: string): string;`
+
+Parses a given source code string using the `content-tag` spec into standard
+JavaScript.
+
+```ts
+import { Preprocessor } from 'content-tag';
+let p = new Preprocessor();
+let output = p.process('<template>Hi</template>');
+```
+
+### `Preprocessor.parse(src: string, filename?: string): Parsed[];`
+
+Parses a given source code string using the `content-tag` spec into an array of
+`Parsed` content tag objects.
+
+```ts
+import { Preprocessor } from 'content-tag';
+let p = new Preprocessor();
+let output = p.parse('<template>Hi</template>');
+```
+
+#### `Parsed`
+
+NOTE: All ranges are in bytes, not characters.
+
+````ts
+interface Parsed {
+  /**
+   * The type for the content tag.
+   *
+   * 'expression' corresponds to a tag in an expression position, e.g.
+   * ```
+   * const HiComponent = <template>Hi</template>;
+   * ```
+   *
+   * 'class-member' corresponds to a tag in a class-member position, e.g.
+   * ```
+   * export default class HiComponent extends Component {
+   *   <template>Hi</template>
+   * }
+   * ```
+   */
+  type: "expression" | "class-member";
+
+  /**
+   * Currently, only template tags are parsed.
+   */
+  tagName: "template";
+
+  /** Raw template contents. */
+  contents: string;
+
+  /**
+   * Byte range of the contents, inclusive of inclusive of the
+   * `<template></template>` tags.
+   */
+  range: {
+    start: number;
+    end: number;
+  };
+
+  /**
+   * Byte range of the template contents, not inclusive of the
+   * `<template></template>` tags.
+   */
+  contentRange: {
+    start: number;
+    end: number;
+  };
+
+  /** Byte range of the opening `<template>` tag. */
+  startRange: {
+    end: number;
+    start: number;
+  };
+
+  /** Byte range of the closing `</template>` tag. */
+  endRange: {
+    start: number;
+    end: number;
+  };
+}
+````
+
 ## Contributing
 
 See the [CONTRIBUTING.md](./CONTRIBUTING.md) file.