A guest list rarely lives inside one app. You might be on PopIn. Your best friend is a WhatsApp person. Your parents use email. One colleague checks nothing except his work inbox. Your sister's friend group is all in iMessage. And somehow they all need to end up RSVP'd to the same event.
The answer is simpler than it sounds.
How the shareable link works
Every PopIn event has a shareable link you can copy from the event page. It's a plain URL. Anyone can open it in any browser, on any device, without a PopIn account. When they land on the page, they see the event details and an RSVP form. They enter their name and a contact for reminders (email or phone), pick Going, Maybe, or Can't make it, and they're on your guest list.
From your side, you see their RSVP exactly the same way you see a signed-up user's RSVP. There's no second-class guest list.
What your guests actually see
When a guest opens your event link for the first time, they land on the event page. They see the event name, the date and time, the location, and whatever you wrote in the description. There's an RSVP form right there on the page. They pick Going, Maybe, or Can't make it, type their name and an email or phone for reminders, and tap submit.
No signup screen. No "create an account to continue." No app store prompt. The whole interaction takes under a minute.
After they RSVP they get a confirmation. If you've enabled calendar links on the event, they can add it straight to their own calendar without having a PopIn account. When you send a broadcast update (new address, time change, parking info), it reaches them via whatever contact they gave when they RSVP'd. From their perspective they're dealing with a webpage, not a platform.
Where to paste the link
Copy it and paste it anywhere. iMessage, WhatsApp, Telegram, Facebook Messenger, a group chat you already have, an email, a text. It works in all of them. You don't need to set up different invitations for different channels. One link, sent wherever your people actually are.
For guests you'd rather invite by email, PopIn has a built-in invite flow where you enter their email address and PopIn sends the invitation for you. Same link, just wrapped in a proper email rather than a raw URL dropped into a chat.
When someone says "I don't use PopIn"
Tell them they don't need to. They don't need an account. They don't need to download anything. They tap the link and fill in two fields.
For guests who are wary of links in general (usually older guests, not always), it helps to add one line of context when you share it. "Here's the event page, just tap to RSVP" goes over better than dropping a raw URL with no explanation.
Inviting someone without a smartphone
If you have guests who won't be RSVPing digitally at all, you can RSVP on their behalf. Open the event page, use the guest RSVP form, and enter their name. You can use your own contact for reminders, or leave the contact field blank if you'll be passing along any updates yourself. It creates a real entry on the guest list and keeps everything in one place.
One thing to avoid
Don't run parallel tracking systems. Some hosts copy RSVPs into a spreadsheet or Notes app because they're not sure the platform captures everything. It's understandable, but it creates a headcount problem: you end up with two lists that gradually diverge and you never quite know which one is right. Trust the guest list in PopIn. If a guest tells you verbally that they're coming, RSVP them yourself from your phone. One list. One number.