Mastodon on any website.

Every Mastodon user lives on a specific instance: a server running the open-source Mastodon software (or a compatible alternative like Pleroma, Akkoma, or GoToSocial). Examples include mastodon.social (the flagship instance run by the Mastodon nonprofit), fosstodon.org (free and open source software focus), hachyderm.io (tech industry), infosec.exchange (security professionals), mas.to (general purpose), and tens of thousands of smaller instances. A handle like @[email protected] tells the world your username and which server hosts your account. Each instance has its own moderation rules, its own API endpoint at instance.tld/api/v1/, and its own community norms. There is no central Mastodon API to call. A widget that wants to embed a Mastodon feed must resolve the instance from the handle and talk directly to that server. Poper does this automatically: paste any handle and the widget hits the right instance API, caches the response at our CDN edge, and renders posts with the same fidelity as the official Mastodon web client.

ActivityPub is the W3C-standard protocol that lets independent Mastodon instances talk to each other. When you follow someone on a different instance, your home server fetches their posts via ActivityPub. When you boost (Mastodon's equivalent of retweet), the boost propagates to every instance that has seen the original post. This federation is why a hashtag widget can pull posts from across the entire Fediverse, not just from one server: instances exchange tagged posts in real time, and the federated timeline aggregates them. ActivityPub support extends beyond Mastodon: Pleroma, Akkoma, Misskey, Pixelfed (federated Instagram), PeerTube (federated YouTube), Lemmy (federated Reddit), and even Threads (Meta announced ActivityPub support in 2024) all speak the same protocol. A Mastodon feed widget that respects the protocol can pull from any of these without special-casing per platform. Poper renders ActivityPub Note objects natively: status content, attachments, content warnings, custom emoji, alt text, and boost attribution all come through correctly.

Mastodon culture treats content warnings (CWs) as a core social norm, not an afterthought. Users wrap potentially sensitive content (politics, death, food, eye contact, body, spoilers) with a CW so readers can choose whether to expand. This consent-based approach is one reason the post-Twitter migration of 2022-2024 found Mastodon comfortable: the CW affordance gives readers control that algorithmic feeds never offered. A Mastodon widget that strips CWs (or worse, displays the wrapped content without the warning) breaks this norm and damages reader trust. Poper preserves CWs exactly: collapsed by default with a click-to-expand affordance, or always shown with a CW header if your site prefers. You can also set a CW keyword filter to hide specific topics from your embed, which is useful for embeds on professional sites where certain CW categories are off-topic. Alt text gets the same respectful treatment: rendered as a caption (the Mastodon norm) rather than hidden in a tooltip.

Between October 2022 (Elon Musk's Twitter acquisition) and early 2024, Mastodon grew from roughly 300,000 monthly active users to over 1 million. The migration was driven by journalists, academics, open-source maintainers, security researchers, and privacy-focused brands who decided centralized platforms were no longer reliable hosts for public discourse. Major moves included: NPR and BBC public-broadcast accounts, government accounts (the EU has multiple instances for its institutions), academic researchers (academia.exchange, mathstodon.xyz, and dozens of discipline-specific instances), open-source projects (the GNOME, Krita, and KDE projects all maintain official Mastodon presences), and privacy-conscious media organizations. For these brands, embedding a Mastodon feed on the marketing site or docs page is a statement: your public communications happen on an open protocol, not a walled garden, and your readers can engage without creating accounts on platforms they distrust. The widget makes that statement loud and visible.

The default values of the Fediverse differ sharply from those of corporate social: no algorithmic feed, no engagement-bait amplification, no advertising, no data sale, and crucially no third-party tracking on embeds. Mastodon instances do not load analytics scripts, do not fingerprint visitors, and do not phone home. A widget that breaks this pattern by injecting cookies, tracking pixels, or fingerprinting libraries violates the platform's culture and gives privacy-aware visitors a reason to bounce. Poper ships a Mastodon embed that respects these values: no cookies set by the widget, no tracking calls to third parties, no fingerprinting, and a privacy policy that explicitly does not collect personal data from widget interactions. For GDPR-heavy sites (European media, academic institutions, healthcare, public-sector), this is a practical advantage: the embed does not trigger the cookie banner, does not require additional consent management, and does not appear in any data processing agreement audit. Combine that with respect for content warnings and alt text and the embed feels native to Mastodon, not bolted on from a corporate social tool.