How to insert a link to an external app (Joplin)

[MC]

I'm using Trello and I find it very useful. I'd like to know if it's possible to insert a link in the description of a card, pointing to an external app, when using it in Windows.

Specifically, when using Trello in windows, how can I insert a link like: "joplin://x-callback-url/openNote?id=270d23fe970e460f881480d3fcbaa563", that usually opens Joplin (https://joplinapp.org/). 

I tried to use the "insert link" function, but it gives me error, prompting me to put a correct link. 

Thanks!

[Alberto Estévez · Accepted solution]

Hi Mario. Thank you for reaching out to the Atlassian Community.

Looks like this could be due to Trello description field only allowing http: or https: links?
Have you tried a different link starting with http: or https:? If it works, it must be due some sort of limitation regarding custom protocol links. Maybe you can search for a workaround to change the link using a link shortener service like https://tinyurl.com/

[MC]

Thank you Alberto, your solution is clever and works, more or less.

Trello allows links like "https://tinyurl.com/dsds3d" but when I click on it, it opens the browser (not Joplin). Clicking in the browser (after an alert) brings me to the Joplin page.  You need 3 clicks, but you finally get to the page. 

You need to shorten all your links before that and this is not so practical. 

Is it there another solution for it? 

[Alberto Estévez]

Happy to help. Because Trello doesn't recognize joplin:// as a valid hyperlink, you can still paste the full link in the card description as plain text. Then, when you need to open it, you can copy and paste it into your browser’s address bar, or manually into the Windows "Run" dialog (Win + R). No ideal, but at least there is a way to link to Joplin from a Trello card.
You could also try to use Joplin with markdown files stored locally, you could try attaching the relevant file directly to the Trello card. While this won’t open it via joplin://, it will give you a way to quickly access the note.

[MC]

Thank you Alberto, I find the first solution to be the best one: 

Paste the link as text in the description, then copy the text and run it with Win + R. It works very well!