diff --git a/index.js b/index.js
index 434f08a..61152b4 100644
--- a/index.js
+++ b/index.js
@@ -20,7 +20,9 @@ const expressions = [
  * Check if `url` is a badge.
  *
  * @param {string} url
+ *   URL to something.
  * @returns {boolean}
+ *   Whether `url` is a badge.
  */
 export function isBadge(url) {
   let index = -1
diff --git a/readme.md b/readme.md
index c2fdc8f..4ace1d3 100644
--- a/readme.md
+++ b/readme.md
@@ -7,35 +7,52 @@
 
 Check if `url` is a badge.
 
-Supports:
+## Contents
 
-*   [x] [`codeclimate`][codeclimate]
-*   [x] [`codecov`][codecov-ci]
-*   [x] [`coveralls`][coveralls]
-*   [x] [`david-dm`][david]
-*   [x] [`fury.io`][fury]
-*   [x] [`github.com` workflows][github]
-*   [x] [`gitter`][gitter]
-*   [x] [`inch-ci`][inch]
-*   [x] [`issuestats`][issuestats]
-*   [x] [`nodei.co`][nodei]
-*   [x] [`saucelabs`][sauce]
-*   [x] [`shields.io`][shields]
-*   [x] [`testling`][testling]
-*   [x] [`travis-ci`][travis-ci]
-*   [x] `opencollective`
+*   [What is this?](#what-is-this)
+*   [When should I use this?](#when-should-i-use-this)
+*   [Install](#install)
+*   [Use](#use)
+*   [API](#api)
+    *   [`isBadge(url)`](#isbadgeurl)
+*   [Data](#data)
+*   [Types](#types)
+*   [Compatibility](#compatibility)
+*   [Contribute](#contribute)
+*   [Security](#security)
+*   [License](#license)
 
-## Install
+## What is this?
+
+This is a tiny package that checks if a given url points to a badge.
 
-This package is ESM only: Node 12+ is needed to use it and it must be `import`ed
-instead of `require`d.
+## When should I use this?
 
-[npm][]:
+You can use this package for example to filter out badges.
+
+## Install
+
+This package is [ESM only][esm].
+In Node.js (version 14.14+, 16.0+), install with [npm][]:
 
 ```sh
 npm install is-badge
 ```
 
+In Deno with [`esm.sh`][esmsh]:
+
+```js
+import {isBadge} from 'https://esm.sh/is-badge@2'
+```
+
+In browsers with [`esm.sh`][esmsh]:
+
+```html
+<script type="module">
+  import {isBadge} from 'https://esm.sh/is-badge@2?bundle'
+</script>
+```
+
 ## Use
 
 ```js
@@ -43,18 +60,57 @@ import {isBadge} from 'is-badge'
 
 isBadge('https://img.shields.io/travis/joyent/node.svg') // => true
 isBadge('https://example.com') // => false
-isBadge(true) // [Error: is-badge expected string]
 ```
 
 ## API
 
-This package exports the following identifiers: `isBadge`.
+This package exports the identifier `isBadge`.
 There is no default export.
 
 ### `isBadge(url)`
 
 Check if `url` is a badge.
 
+## Data
+
+This project supports:
+
+*   [x] [`codeclimate`][codeclimate]
+*   [x] [`codecov`][codecov-ci]
+*   [x] [`coveralls`][coveralls]
+*   [x] [`david-dm`][david]
+*   [x] [`fury.io`][fury]
+*   [x] [`github.com` workflows][github]
+*   [x] [`gitter`][gitter]
+*   [x] [`inch-ci`][inch]
+*   [x] [`issuestats`][issuestats]
+*   [x] [`nodei.co`][nodei]
+*   [x] [`saucelabs`][sauce]
+*   [x] [`shields.io`][shields]
+*   [x] [`testling`][testling]
+*   [x] [`travis-ci`][travis-ci]
+*   [x] `opencollective`
+
+## Types
+
+This package is fully typed with [TypeScript][].
+It exports no additional types.
+
+## Compatibility
+
+This package is at least compatible with all maintained versions of Node.js.
+As of now, that is Node.js 14.14+ and 16.0+.
+It also works in Deno and modern browsers.
+
+## Contribute
+
+Yes please!
+See [How to Contribute to Open Source][contribute].
+
+## Security
+
+This package is safe.
+
 ## License
 
 [MIT][license] © [Titus Wormer][author]
@@ -79,6 +135,14 @@ Check if `url` is a badge.
 
 [npm]: https://docs.npmjs.com/cli/install
 
+[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
+
+[esmsh]: https://esm.sh
+
+[typescript]: https://www.typescriptlang.org
+
+[contribute]: https://opensource.guide/how-to-contribute/
+
 [license]: license
 
 [author]: https://wooorm.com