Bridgy Fed

Personal web site

Fediverse profile via Bridgy Fed

Bridgy Fed turns your web site into its own fediverse account, visible in Mastodon and beyond. You can post, reply, like, repost, and follow fediverse accounts by posting on your site with microformats2 and sending webmentions. Bridgy Fed translates those posts into ActivityPub, and when people inside the fediverse respond, it sends those responses back to your site as webmentions.

This isn't syndication or POSSE! You don't need an account on Mastodon or anywhere else. Bridgy Fed makes your site a first class member of the fediverse. People there will see your posts directly from your site, and vice versa.

Bridgy Fed takes some technical know-how to set up, and there are simpler (but less powerful) alternatives. If you just want your site's posts to show up in the fediverse, without any other interactions, consider an RSS or Atom feed bot instead. Or, if you want to cross-post to an existing Mastodon account, try Bridgy.

Setup

How do I set it up?
How do I set up my profile?
How do I update my profile?
Where's my user page and dashboard?

Usage

How do I post to the fediverse?
Which of my posts will show up in the fediverse?
Which fediverse apps are supported?
How does it decide which parts of my posts to include?
What's up with the visible fed.brid.gy links in my fediverse posts?
How do I reply to a fediverse post?
How do I favorite (aka like) or boost (aka repost) a fediverse post?
How do I follow someone?
How do I unfollow someone?
How do I include an image in a post?
How do I use hashtags?
How do I edit an existing post?
How do I delete a post?
Can I publish just one part of a page?
How do fediverse replies, likes, and other interactions show up on my site?
How do I read my fediverse timeline/feed?
Are there notifications?
How can people on the fediverse find and follow me?
How can I see what my posts look like inside the fediverse?
Can I make my posts show up when people search for them in the fediverse?
I tried it, and it didn't work!

About

Who are you? Why did you make this?
How much does it cost?
What do you do with my data?
How long has this been around?
What are the terms of service?
I found a bug! I have a feature request!
I found a security vulnerability!

Development

How are the different protocols translated?
How are errors handled?

Setup

How do I set it up?
1. Your site needs to support SSL. Bridgy Fed uses your domain as your identity, so it depends on SSL to prove that you own it.
2. Configure your site to redirect these URL paths to the same paths on https://fed.brid.gy/, including query parameters:
3. Add webmention support to your site. This is strongly recommended, but technically optional. You don't have to automate the webmentions to Bridgy Fed to federate your posts, and you don't have to accept the inbound webmentions that Bridgy Fed sends, but you'll have a much better experience if you do. Check out the IndieWeb wiki for instructions for your web server.
How do I set up my profile?
Your site's fediverse profile comes from the microformats2 representative h-card on your site's home page. Here's a minimal example to set your name and a profile picture:
```
<span class="h-card">
  <a rel="me" href="/">Alice Foo</a>
  <img class="u-photo" src="/me.jpg" />
</span>
```
If you want to set a header image, add a u-featured image to your h-card, eg:
```
<img class="u-featured" src="/my-header.png" />
```
By default, your fediverse address will be @yourdomain.com@yourdomain.com. Many services (eg Mastodon) default to only showing the username, so this generally shows up as just @yourdomain.com in posts, and the full address appears on hover.

We recommend this for simplicity and predictability, for everyone else as well as you, but if you want a different username, you can set it by adding an acct: u-url link inside your h-card with username@yourdomain.com, eg:
```
<a class="u-url" href="acct:alice@yourdomain.com"></a>
```
How do I update my profile?
If you've changed the representative h-card on your site's home page, and you want to update your profile in Mastodon to match, click the button next to your domain on your user page. Alternatively, you can send a webmention from your home page to https://fed.brid.gy/.
Where's my user page and dashboard?
Enter your domain here to see your user page. It shows your site's current status, recent interactions, remote follow UI, and links to your timeline feeds in various formats.

Usage

How do I post to the fediverse?
Create a post with the h-entry microformat on your web site. Many web servers include this or compatible microformats automatically. The post can be a note, article, like, repost, reply, or follow. For example:
```
<div class="h-entry">
  <p class="e-content">Two naked tags walk into a bar. The bartender exclaims, "Hey, you can't come in here without microformats, this is a classy joint!"</p>
  <a class="u-bridgy-fed" href="https://fed.brid.gy/"></a>
</div>
```
Mastodon preserves HTML links and line breaks, but removes all other formatting and tags. Other fediverse sites vary in their HTML handling.

Then, include a link (optionally blank) to https://fed.brid.gy/ in that post and send Bridgy Fed a webmention. That webmention will trigger Bridgy Fed to forward your post into the fediverse. Your web server may send the webmention automatically if it supports them, or you can send it manually.

(The u-bridgy-fed class isn't strictly necessary, but it's useful in some cases to prevent microformats2 parsers from interpreting the link as an implied u-url.)
Which of my posts will show up in the fediverse?
Only the ones you explicitly trigger with a webmention. Bridgy Fed doesn't automatically create posts in the fediverse based on your site's Atom feed, HTML, or anything else. It only create posts in the fediverse on an opt in basis, per post, via webmention.
Which fediverse apps are supported?
Bridgy Fed currently supports at least these major fediverse apps:
- Mastodon, details, more, more
- PeerTube, details
- Friendica, details
- Misskey, probably, details
- Hubzilla, probably, details
...and work is ongoing to support these:
- Pleroma, details
- Pixelfed, details
- Akkoma, details
- Lemmy, details
- GNU Social, details
diaspora* is unlikely because they use their own federation protocol, not ActivityPub. Details.
How does it decide which parts of my posts to include?
Magic! Most major blog engines and CMSes are supported out of the box, no setup necessary. Bridgy Fed looks for microformats in your HTML, first the microformats2 e-content class and then the legacy entry-content class. It also understands more advanced microformats2 classes like in-reply-to, u-like-of, u-repost-of, and u-photo.

Bridgy Fed sends the full contents of all posts, specifically everything inside e-content, to the fediverse. However, not all fediverse apps currently show the full contents of all posts.

For example, text-based posts fall into two broad buckets: short notes, eg tweets and toots, and longer articles, eg blog posts. In the IndieWeb, we differentiate based on whether the post has a title: articles generally have titles, notes don't.

Mastodon currently shows the full text of notes, but for articles, it only shows their titles and a link to the full article. This is because Mastodon and most other fediverse apps are designed primarily for smaller notes, not longer articles.
What's up with the visible fed.brid.gy links in my fediverse posts?
These can happen for a couple reasons. For articles, this is expected behavior, as described above. The link is a Bridgy Fed URL that redirects to the original post on your web site. This is because Mastodon requires ActivityPub (ie fediverse) object URLs to use the same domain that serves them, which in this case is fed.brid.gy. We know it's awkward; sorry for the ugliness!

Otherwise, this may be the invisible fed.brid.gy link that's required to trigger Bridgy Fed. Mastodon will show a preview of links even if their text is blank, so if your link is inside your e-content microformats2 element, that's probably what's happening. You can prevent that by moving it outside of e-content. It can go anywhere in your HTML!
How do I reply to a fediverse post?

Put the reply in a new post on your web site, and include a link to the fediverse post you're replying to with class u-in-reply-to, as if you were publishing a normal IndieWeb reply. For example:

<div class="h-entry">
  <p class="e-content">Highly entertaining. Please subscribe me to your newsletter.</p>
  <a class="u-in-reply-to" href="https://indieweb.social/@tchambers/109243684867780200"></a>
  <a class="u-bridgy-fed" href="https://fed.brid.gy/"></a>
</div>

How do I favorite (aka like) or boost (aka repost) a fediverse post?

Favoriting and boosting are almost exactly the same as replying. The only difference is that you use u-like-of for a favorite/like or u-repost-of for a boost/repost.

<a class="u-like-of" href="https://octodon.social/@cwebber/109405439825087368"></a>

<a class="u-repost-of" href="https://prodromou.pub/@evan/109390803478257847"></a>

How do I follow someone?
If your web site supports IndieAuth, go to your user page, click the Following link, then enter the address of the account you want to follow.

You can also follow someone by posting an IndieWeb follow on your site, including the u-follow-of microformats2 class, and sending a webmention to Bridgy Fed. Your site may do that automatically if it supports webmentions. For example:
```
<div class="h-entry">
  I'm now following <a class="u-follow-of" href="https://octodon.social/@cwebber">@cwebber@octodon.social</a>!
  <a class="u-bridgy-fed" href="https://fed.brid.gy/"></a>
</div>
```
This method doesn't require IndieAuth, and it can be automated.
How do I unfollow someone?
Go to your user page, click the Following link, find the account you want to unfollow, and click the X next to their address. Like following, this requires your web site to support IndieAuth.
How do I include an image in a post?

Use <img class="u-photo"> for the image in your post. For example:

<img class="u-photo" src="/full_glass.jpg" />
I love scotch. Scotchy scotchy scotch.

How do I use hashtags?
Use p-category and link the hashtag to a fully qualified URL. (Any URL you want!) Fediverse sites like Mastodon will generally rewrite the link to point to a search for that hashtag on the local instance. For example:
```
<div class="h-entry">
  <p class="e-content">
    just setting up my feddr
    <a href="https://mysite.com/tag/throwback" class="p-category">#throwback</a>
  </p>
</div>
```
The leading # character on the hashtag text is optional. If you don't include the hashtag in e-content, or include it but not inside an <a> link, fediverse sites won't add the hashtag text or link themselves, but your post will still be indexed in searches for that hashtag.
How do I edit an existing post?
Edit the post on your web site, then send another webmention to Bridgy Fed for it. Bridgy Fed will refetch the post and send an Update activity for it to the fediverse.
How do I delete a post?
First, delete the post on your web site, so that HTTP requests for it return 410 Gone or 404 Not Found. Then, send another webmention to Bridgy Fed for it. Bridgy Fed will refetch the post, see that it's gone, and send an Delete activity for it to the fediverse.
Can I publish just one part of a page?
If that HTML element has its own id, then sure! Just put the id in the fragment of the URL that you publish. For example, to publish the bar post here:
```
<div id="a" class="h-entry">foo</div>
<div id="b" class="h-entry">bar</div>
<div id="c" class="h-entry">baz</div>
```
...just add the id to your page's URL in a fragment, e.g. http://site/post#b here.
How do fediverse replies, likes, and other interactions show up on my site?
To receive likes, reposts, replies, @-mentions, and follows from the fediverse, just make sure your site accepts webmentions! Bridgy Fed translates those interactions and sends them to your site as webmentions. The source URL will usually be a proxy page on fed.brid.gy. For best results, make sure your webmention handler detects and handles u-url links.
How do I read my fediverse timeline/feed?
Your user page has links to your fediverse timeline/feed, ie posts from people you follow, in HTML, Atom, and RSS formats. Add them to your feed reader or read them in your browser!
Are there notifications?
Yes! Your user page shows a feed of your notifications - mentions, replies, likes, reposts, follows, etc - in h-feed format, which you can subscribe to in any social reader. Let us know if you want other formats!
How can people on the fediverse find and follow me?
They can search for your web site in any Mastodon instance! Often you can just enter your domain, eg yourdomain.com, in any Mastodon search box. If that doesn't work, try your full fediverse address, eg @yourdomain.com@yourdomain.com. This can be finicky now and then, but it usually works.

Your user page has a "Following" link that shows you everyone on the fediverse who's currently following you. It also has a "remote follow" form that lets people enter their fediverse address and follow you directly.
How can I see what my posts look like inside the fediverse?
This varies by fediverse app. For Mastodon, open your list of followers in Bridgy Fed and click on one to open their profile. Then, inside that Mastodon instance, search for your site's address, click on it in the search results, and you'll see your fediverse profile and all of your posts that were delivered to that instance. This may not be all of them, depending on how long and when people on that instance have been following you.

This general process should often work in other fediverse apps too.

Note: in Mastodon, each of your posts on a given instance will have a permalink inside that instance, eg mastodon.social/@snarfed.org@snarfed.org/109729052169033033, but those permalinks only go to Mastodon if you're logged into that instance. If you're not, they redirect to the original post on your site.
Can I make my posts show up when people search for them in the fediverse?
Yes! Add this line of HTML to each post that you publish with Bridgy Fed and want to be searchable, replacing [URL] with that post's URL:
```
<link rel="alternate" type="application/activity+json" href="https://fed.brid.gy/r/[URL]">
```
Search is intentionally limited in Mastodon and much of the overall fediverse, so this won't index the full text of your posts, but it will make them show up in search results when you search for your post's full URL, which people commonly do in the fediverse to find and interact with posts.
I tried it, and it didn't work!
Check out your user page! It detects and describes common problems with your setup, and it shows your recent interactions and detailed logs.

About

Who are you? Why did you make this?
I'm Ryan Barrett. I'm just a guy who likes the web and owning my data.
How much does it cost?
Nothing! Bridgy Fed is small, and it doesn't cost much to run. We don't need donations, promise.

If you really want to contribute, file an issue or send a pull request, or donate to the IndieWeb!
What do you do with my data?
Nothing! Bridgy Fed isn't a business, and never will be, so we don't have the same motivations to abuse your data that other services might. More concretely, Bridgy Fed won't ever send you email, it stores as little of your PII (personally identifiable information) as possible, and it never has access to any of your passwords.
How long has this been around?
I started thinking about bridging federated social networks and peer to peer networks when I discovered them in the early 2000s. I started talking about bridging them to the IndieWeb in 2016, led a session on it at IndieWeb Summit in July 2017, wrote up concrete designs soon after, started working on Bridgy Fed in August 2017, and launched it on October 22, 2017.
What are the terms of service?
Bridgy Fed's terms of service are very simple. You agree not to deliberately attack, breach, or otherwise harm the service. If you manage to access private keys or other private data, you agree to report the vulnerability and not use or disclose that data.

Otherwise, you may use the service for any purpose you see fit. However, we may terminate or block your access for any reason, or no reason at all. (We've never done this, and we expect we never will. Just playing it safe.)

Do you an administer an instance or other service that Bridgy Fed interacts with? If you have any concerns or questions, feel free to file an issue!
I found a bug! I have a feature request!
Great! Please file it in GitHub. Thank you!
I found a security vulnerability!
Oof. Thank you for reporting it! Please send details to security@brid.gy. We may provide monetary awards for reports of significant vulnerabilities, eg reading or modifying stored access tokens, if you follow these rules:
- Vulnerabilities must be in the application itself, not unrelated services like email (eg SPF/DKIM/DMARC).
- Out of scope: rate limiting, XSS/CSRF attacks (Bridgy Fed has no authenticated sessions or private data accessible to users), /admin/* pages.
- Public user data is intentionally public. That's not a vulnerability.
- No automated fuzzing, DoSes, or other high volume traffic. We block this traffic, and it will disqualify you from any possible award.
Otherwise, the code is open source, feel free to try to break in, let us know if you succeed!

Development

How are the different protocols translated?

Here are internal details on how Bridgy Fed translates user identity and events between protocols, including some like Nostr and Bluesky/AT Protocol that aren't launched here, or even fully implemented or thought through yet. Caveat hacker!

In the tables below, BF is Bridgy Fed, enhanced is users who have done extra setup for BF, basic is users who haven't. Green parts have been implemented and running here for years, the rest are still in the early design phase.

Here's how we (hope to) translate user identity between protocols. Specifically, each cell shows how a user in a given row is identified to the protocol in a given column.

	Web	ActivityPub	AT Protocol	Nostr
Web	-	basic: `@[domain]@fed.brid.gy` enhanced: `@[domain]@[domain]`	users: domain as handle code: `did:plc` generated by BF	basic and code: `npub...` public key generated by BF enhanced: domain, if NIP-05 enabled
ActivityPub	Fediverse profile URL	-	users: `[username].[instance]` (fabricated domain) code: `did:plc` generated by BF	`npub...` public key generated by BF
AT Protocol	PDS web frontend profile URL (how will we get this?)	`@[handle]@fed.brid.gy`	-	basic and code: `npub...` public key generated by BF enhanced: handle domain, if NIP-05 enabled
Nostr	NIP-05 domain or BF user page	`@[NIP-05]@fed.brid.gy` or `@[npub...]@fed.brid.gy`	users: NIP-05 domain, if available code: `did:plc` generated by BF	-

Here's how we (hope to) translate events and operations between protocols, both inbound to and outbound from Bridgy Fed.

	Web	ActivityPub	AT Protocol	Nostr
User discovery inbound	serve `h-card` on BF user page	basic: serve WebFinger and AP actor on fed.brid.gy enhanced: user's site serves and redirects WebFinger to fed.brid.gy	resolve DID, serve DID document with fed.brid.gy PDS	NIP-39 (kind 0) query to BF (or other?) relay
User discovery outbound	Fetch home page, parse `h-card`	look up WebFinger, fetch AP actor	resolve DID, subscribe to PDS repo, extract profile object?	discover user's relays with NIP-65, query NIP-39 to get profile
Publish inbound	webmention to fed.brid.gy	deliver to fed.brid.gy inbox, user or shared	subscribe to user's PDS repo on fed.brid.gy	publish event to BF relay
Publish outbound	serve on BF user page followings `h-feed`	deliver to recipient's inbox	serve repo diff via `sync` XRPCs to subscribing BGSes	serve to subscribers
Follow inbound	users: UI on BF user page code: webmention with `u-follow-of`	`Follow` activity delivered to BF user inbox	receive `sync.subscribeRepos`?	user's client sends `REQ` to BF relay
Follow outbound	webmention with BF proxy HTML page as source	deliver `Follow` to followee's inbox	call `sync.subscribeRepos` on followee's PDS?	discover followee's relay(s) with NIP-65, send them a `REQ`
Response inbound	webmention to a BF proxy page	`Create`, `Like`, `Announce` delivered to BF user inbox	response object received from a subscribed repo? (what if it's from a user we don't subscribe to?)	NIP-10 response event received at BF relay or other relay
Response outbound	same as follow outbound, with the corresponding response data type

How are errors handled?
"It's complicated." ...well, at least a bit. There are different philosophies on how to architect request handling and error propagation in these kinds of server-to-server protocols.

One common bit of received wisdom is to handle all requests asynchronously, in the background. Do minimal request validation synchronously, if necessary, then return HTTP 202 (or 201) and enqueue the request in a background task queue to be processed offline. This is widespread in ActivityPub implementations, for example. Webmention even recommends it as a SHOULD!

Upon receipt of a POST request containing the source and target parameters, the receiver SHOULD verify the parameters (see Request Verification below) and then SHOULD queue and process the request asynchronously, to prevent DoS attacks.

It's a good idea, but it has drawbacks. Most importantly, it hides errors. Sending side implementations always receive HTTP 202 responses, even when their requests fail in the background, and there's no standard or widely implemented way to get more information or debug. Webmention nods to this and says receivers can return a per-request status URL in the Location response header, but that's not widely implemented, and ActivityPub has no corresponding mechanism. This makes development and interop materially harder, especially in these protocols' loosely connected ecosystems. Mastodon's issue tracker, for example, is full of issues complaining "Mastodon isn't working with my code, but I can't tell why!"

Bridgy Fed currently takes a compromise position. It handles most requests synchronously, blocks on delivering them to the destination protocol, and propagates any errors back to the sender with the appropriate HTTP response status code and body (often JSON). Delivering posts to ActivityPub followers is one exception; it currently delivers to inboxes serially, so it often takes many minutes, which is uncomfortably long for many HTTP clients.

Converting to webmention is another exception. Bridgy Fed uses webmentions and microformats2 to provide social interactions for web sites, but unlike with other protocols, it doesn't require web sites to support them. So, Bridgy Fed doesn't currently convert webmention failures (or lack of support) to errors in other protocols. It records those failures, and shows them in the UI on your user page, but returns success to the sending side in its own protocol.