You can, but maybe you shouldn't. Given that this post is in the fediverse community, I don't feel too bad about mentioning that Lemmy is part of a federated network with PieFed and MBIN (I try not to bollock on too much about the platform I happen to be using).

In the ActivityPub JSON for this post, there is no indication that this field contains MarkDown. If anything, it says the opposite, it says it contains HTML. It's therefore not unreasonable for other platforms to render it as such.

Given this, and the poor support for mobile clients indicated in the comments, and the fact that it's only a subset of MarkDown tags, but include ones that aren't part of CommonMark standard, I'd argue that it's not necessarily a good idea.

[–] flamingos@feddit.uk 13 points 3 weeks ago (1 children)

In the ActivityPub JSON for this post, there is no indication that this field contains MarkDown. If anything, it says the opposite, it says it contains HTML. It’s therefore not unreasonable for other platforms to render it as such.

Actually, the name property is explicitly plain text, it shouldn't contain any type of markup, whether that be markdown or HTML.

[–] andrew_s@piefed.social 3 points 3 weeks ago (1 children)

Oh, wow. Thanks.

For clarity, I wasn't intending to say that PieFed treats that field as HTML (it treats it as text), I just meant that if you were looking at that JSON, and being a bit lazy like me and not looking at specs, then it wouldn't be unreasonable to assume that the 'mediaType' field also refers to 'name' (rather than a 'content' field which this post doesn't happen to have).

Anyway, this seems to be even more reason why MD shouldn't be put in titles, and front-ends shouldn't be encouraging the practise by rendering it.

[–] kat@orbi.camp 2 points 3 weeks ago

Eh, I'll probably use italics tho, just like I did * in reddit.

[–] AA5B@lemmy.world 2 points 3 weeks ago (1 children)

In the ActivityPub JSON for this post, there is no indication that this field contains MarkDown. …. it says it contains HTML

This seems like a bug. Regardless of what clients may support, the json ought to accurately describe fields

[–] andrew_s@piefed.social 5 points 3 weeks ago

Another commenter (who's contributed code to Lemmy) pointed to a link that provides the specification for that field: "A simple, human-readable, plain-text name for the object. HTML markup MUST NOT be included."

So in this case, it's more that the JSON looks a bit ambiguous: 'mediaType' is only referring to the format of the text in a post's body, but - unlike me - you'd also need to be aware of the spec to know that it doesn't apply to the title.

[–] schnurrito@discuss.tchncs.de 1 points 3 weeks ago (2 children)

Do you know a way to see the ActivityPub JSON for fediverse objects?

[–] BentiGorlich@gehirneimer.de 5 points 3 weeks ago

you can use https://browser.pub/ I like it very much for that use case :)

[–] andrew_s@piefed.social 5 points 3 weeks ago (1 children)

Yes - it's easy to do from a command line. For this post, it would be:

curl --header 'accept: application/activity+json' --location https://lemmy.world/post/24241974 | jq .

it looks like

{  
  "@context": [  
    "https://join-lemmy.org/context.json",  
    "https://www.w3.org/ns/activitystreams"  
  ],  
  "type": "Page",  
  "id": "https://lemmy.world/post/24241974",  
  "attributedTo": "https://lemmy.world/u/amon",  
  "to": [  
    "https://lemmy.world/c/fediverse",  
    "https://www.w3.org/ns/activitystreams#Public"  
  ],  
  "name": "By the way, you can have `Markdown` in Lemmy post titles",  
  "cc": [],  
  "mediaType": "text/html",  
  "attachment": [],  
  "commentsEnabled": true,  
  "sensitive": false,  
  "published": "2025-01-13T20:48:50.824942Z",  
  "language": {  
    "identifier": "en",  
    "name": "English"  
  },  
  "audience": "https://lemmy.world/c/fediverse"  
}

[–] schnurrito@discuss.tchncs.de 1 points 3 weeks ago

Thanks, will try that out