Although the <strong>Frames Protocol</strong><em>could</em> be used outside of <strong>Farcaster</strong>, at the time of writing, <strong>Farcaster</strong> clients are the only major (client-side) platform to support it.
(The server-side of the <strong>Frames Protocol</strong>, which is called a <strong>Frame Server</strong>, is an HTTP resource — which some might loosely call an HTTP (or HTTP) URL.)
Before we get into the <strong>Frames Protocol</strong> let's quickly go over <strong>Farcaster</strong> — since the <strong>Frames Protocol</strong> originated with <strong>Farcaster</strong>.
</p>
<p>
<strong>Farcaster</strong> is a decentralized social-media network — and is similar in many ways to other decentralized social-media networks, such as
the <strong>Fediverse</strong> (which includes Mastodon, Pleroma, Pixelfed, PeerTube, Misskey, Lemmy, Kbin, GreatApe, Akkoma, etc),
and
<strong>Bluesky</strong>.
</p>
<p>
And in particular, <strong>Farcaster</strong> is a <strong>micro-blogging</strong> social-media network platform.
</p>
<p>
The most famous <strong>micro-blogging</strong> social-media network platform is <strong>Twitter.</strong>.
But the <strong>Fediverse</strong>'s <strong>Mastodon</strong>, <strong>Akkoma</strong>, <strong>Misskey</strong>, <strong>Pleroma</strong> and others are also <strong>micro-blogging</strong> social-media network platforms.
And so too is <strong>Bluesky</strong>.
</p>
<p>
All of these (including <strong>Farcaster</strong>) are similar to <strong>Twitter.</strong>.
</p>
</section>
<section>
<h2>HTML</h2>
<p>
One of the main language of the <abbrtitle="World Wide Web">Web</abbr> is <abbrtitle="HyperText Markup Language">HTML</abbr>.
</p>
<p>
<abbrtitle="HyperText Markup Language">HTML</abbr> looks like this:
</p>
<pre><code>
The following is <b>bold</b> and <a href="http://example.com/">this</a> is a link.
</code></pre>
<p>
Although typically, <abbrtitle="HyperText Markup Language">HTML</abbr> comes as a whole page (rather than a fragment), and thus usually looks more like this:
When creating a <strong>Frames Protocol</strong> application, you can effectively ignore almost all of <abbrtitle="HyperText Markup Language">HTML</abbr> except for one <abbrtitle="HyperText Markup Language">HTML</abbr> element — the <abbrtitle="HyperText Markup Language">HTML</abbr><meta> element.
The <strong>Frames Protocol</strong> only uses the <abbrtitle="HyperText Markup Language">HTML</abbr><meta> element.
And it (the <strong>Frames Protocol</strong>) uses the <abbrtitle="HyperText Markup Language">HTML</abbr><meta> element in a very particular way.
If you look at the old <abbrtitle="HyperText Markup Language">HTML</abbr> 2.0 specification (i.e., <ahref="https://datatracker.ietf.org/doc/html/rfc1866">IETC RFC-1866</a> in <ahref="https://datatracker.ietf.org/doc/html/rfc1866#section-5.2.5">section 5.2.5.</a>), which was created back in the 1990s, you can see how the <abbrtitle="HyperText Markup Language">HTML</abbr><meta> element was defined back then.
The <strong>Frames Protocol</strong> usage of the <abbrtitle="HyperText Markup Language">HTML</abbr><meta> element takes inspiration from the <ahref="https://ogp.me/">OpenGraph</a> protocol.
The following is <b>bold</b> and <a href="http://example.com/">this</a> is a link.
</p>
</body>
</html>
</code></pre>
<p>
Since there is a lot of <abbrtitle="HyperText Markup Language">HTML</abbr> code there, let's just focus on the <ahref="https://ogp.me/">OpenGraph</a> part of it:
