Add the button to your site

Every guide shows the file to edit and the snippet to paste. It is the same script tag everywhere; what changes is where your platform keeps the template for a single post.

Plain HTML

Any page you write by hand or generate yourself.
WordPress

Block themes in the Site Editor, or any theme with a few lines of PHP.
Ghost

Code injection for the script, then your theme's post template or an HTML card.
Hugo

Override your theme's single-page template with one line after the content.
Jekyll and GitHub Pages

Add it to _layouts/post.html, even when the layout comes from a theme gem.
Eleventy

Put it in the post layout under _includes/.
Astro

An inline script and the element in your blog post layout.
Next.js and React

Load the script once with next/script and render the element in JSX.

Before you start: get a key

Sign in with GitHub on the dashboard and add your site.
Create a button. In its allowed origins, list every address your site is served from, one per line and without a path, such as https://example.com. Add the address you preview on locally too, exactly as the browser shows it. A page on an origin that is not listed cannot load the button, so nobody else can use your key.
Copy the key. It starts with pk_. Below, it stands in as pk_YOUR_BUTTON_KEY.

Using a coding agent?

Claude Code, Cursor and similar agents can do the edit for you. The install section has a short prompt to paste into one; it asks for your key and puts the tag in your post template.