Re: Standardizing the printed and HTML version of a an ActivityPub handle

I forgot to mention the relevant RFC for the acct: URI prefix, which is 
here:

https://datatracker.ietf.org/doc/html/rfc7565

Evan

On 2025-09-17 5:16 p.m., Evan Prodromou wrote:
> So, this is a really interesting topic!
>
> In terms of the "right" format for ActivityPub accounts, I'd suggest 
> sticking with bare Webfinger, username@domain.tld. If I were make a UI 
> for submitting Fediverse account IDs, that's probably the format I'd use.
>
> From the URI perspective, for Webfinger identifiers, 
> `acct:username@domain.tld` is the "right" way to do it.
>
> Having that be clickable means that users can assign apps to "handle" 
> the URI. For example, a user could assign the Elk.zone Web application 
> to handle those URIs, and show the profiles page with profile, outbox, 
> followers, friends, etc. as well as affordances to follow, block, 
> message, mention, etc.
>
> There are browser features and operating system features to define a 
> handler for an URI protocol prefix. For browsers, 
> registerProtocolHandler() is the way to go.
>
> https://developer.mozilla.org/en-US/docs/Web/API/Navigator/registerProtocolHandler 
>
>
> Theoretically, assigning an app to handle the "acct:" prefix would let 
> you create a link like this in HTML:
>
> <a href="acct:evan@cosocial.ca">Evan Prodromou</a>
>
> ...and it would just work.
>
> There are two problems with this, though.
>
> 1. Webfinger identifiers are primarily (?) used for ActivityPub 
> actors, but not exclusively. It seems like a low risk, but some 
> non-zero percentage of users might want Webfinger addresses to be 
> handled by... something else?
>
> 2. HTML5 has an allowlist of URI prefixes that can be registered to be 
> handled, and "acct:" is not on the list. You *can* use whatever prefix 
> you want, as long as it start with "web+", so registering the 
> "web+acct:" prefix would let you write links like this:
>
> <a href="web+acct:evan@cosocial.ca">Evan Prodromou</a>
>
> Anywho, long story short: I did a little experimentation with this on 
> https://acct.swf.pub/ ; you can register that web site to handle 
> web+acct: URIs, and it should then handle them correctly. 
> (https://acct.swf.pub/test.html has a test link you can try). I need 
> to get back to polishing it up, but I think this is an interesting 
> area to pursue.
>
>
> On 2025-09-16 4:31 p.m., Johannes Ernst wrote:
>> During registration for FediForum (which is coming up again, by the 
>> way!) we are asking people for their social web handles:
>>
>> Here is a selection of what they give us when they probably mean 
>> ActivityPub
>>
>> @foo@bar
>> AP: @foo@bar
>> https://bar/@foo
>> foo@bar
>> foo (???)
>> acct:foo@bar
>>
>> Is it time to define a canonical version?
>>
>> Perhaps there could also be a canonical, clickable HTML version.
>>
>> Just a thought.
>>
>> Cheers,
>>
>>
>>
>>
>> Johannes.
>>
>>
>

Received on Wednesday, 17 September 2025 21:22:43 UTC