Keep the WhatsApp group. Every attendee is already in it, it costs nothing, and since May 2024 it does RSVPs. Use it for the conversation. It drops state, though: the hotel list, Tuesday's arrivals, and which of the fourteen dinner proposals is still on. heer(ish) sits next to the group and holds exactly that, for the 50 to 500 people who travelled in.
What the group does well
Reach. The group already contains the two people who will never open a new link, and a single group takes 1,024 members, more than any event we serve. Then there are events. Since 1 May 2024 anyone in a group can create one and the others reply, so the group sees who is coming. In April 2025 that grew a "maybe", a plus-one, an end time and pinning. In January 2026 came custom reminders and member tags. Polls got an end time and hidden voter names in August 2026, the same update that brought @all. For "dinner at eight, who's in?" that is plenty, and it is free.
Where it drops things
| You need | WhatsApp group | heer(ish) |
|---|---|---|
| Who is staying at which hotel | Someone asks, thirty people answer, and the answers have scrolled away by lunch. Live Location shows where you are right now, on a timer, to everyone in the chat. | A map with hotels and the faces on them. Always a named place, never a coordinate. |
| Who arrives when | Same thread, and it scrolls away just as fast. | Arrival and departure on every card and in the people list. |
| Plans | Events with RSVP, maybe, plus-one and reminders. Fourteen of them in one scroll. | One list of plans with who's going, and a calendar file for each. |
| Someone who joins late | Sees nothing from before they joined. Since February 2026 an admin can send them the last 25 to 100 messages, by hand. | The map and the list are the current state, whenever you open them. |
| Phone numbers | Every member of an ordinary group sees every number. WhatsApp's own Communities guide warns admins that one @mention in the announcement group "will expose that contact's phone number to the entire community". Usernames are rolling out through 2026 and hide the number from new contacts only. | No phone number unless an attendee puts one on their own card. |
| Noise | In one US and UK survey 40% said group chats overwhelm them, and muting is the standard response. WhatsApp ships a "Highlights only" setting for that reason. | No thread to keep up with. Notifications stay off until you switch them on, and then cover only announcements and the plans you joined. |
| After the event | The group lives on, with every number in it, until the last admin deletes it. | Deleted 14 days after the last day, 30 in the US region. |
| Adding people | Adding a number to a group is processing personal data. In 2025 the Spanish regulator fined a company €70,000 for adding a worker's personal number to a work group without a legal basis. | Attendees add themselves and decide what goes on the card. |
Why the chat loses state
The hotel list was correct at 14:02 on the day someone asked, and every message since has pushed it further up. Pinning helps for one thing at a time. A late joiner never sees it. And the organiser who wants to know how many people are at the Linden on Thursday scrolls, counts, and asks again. The conference in Chicago that heer(ish) was first built for ran on exactly that stack, a group plus a hotel spreadsheet plus a Google My Map, and the sheet was wrong from the first person who changed hotels.
A chat also never forgets. Once the numbers are in the group they are on 200 phones, and WhatsApp's privacy setting that stops strangers adding you cuts the other way for an organiser, because since 2019 anyone can refuse to be added at all.
Use both
heer(ish) is one link. Pin it in the group on day one and say what it is: the map and the plans. The talk stays in WhatsApp, where it belongs, and the things people need to look up twice a day sit on a page that is still correct when they look. Two weeks after the last day that page is gone, and the group is yours to keep or delete.