Do guests need an account to reply through the link?
They open the link and answer on the page: reply button, plus-one choices if you allowed them, a note field if you asked for one. Nothing needs building, and nobody has to search chat history to find what they promised.
Should the link go before or after the facts?
After. The guest needs what, when, where before being asked to act, and the link placed right after the ask reads as the natural next step. A link that arrives before the date is a mystery, not a convenience.
What if the link preview does not load in the chat?
It still taps through, so send it anyway, but check once on your own phone before blasting the list. Sending the link on its own line, with a moment before the rest of the text, gives the preview room to render.
Can I shorten or customise the link?
Every event gets a live link on a myjoyfullday subdomain plus a shorter path URL; use either in the message. There are no custom domains, and the honest answer is that guests do not read URLs, they read the sentence before them.
What about older guests who never tap?
Print the page address or a QR code on a card, and take their reply by phone yourself. The list has room for answers entered without a tap, and the page still does what the phone cannot: count everyone in one place.
Do guests see a deadline even if the message omits it?
The page shows the date beside the reply button, so the deadline always exists somewhere. The message should still carry it; a date in the chat becomes a decision now, while a date on the page waits for a tap.