For coordinators & planners
Every other supplier works their own leg. You reconcile four versions of the same timeline — so the software should hold all of them, not one.
The DJ, the photographer, the videographer and the booth all attach to one wedding. Each of them sees their own work. You see all of it.
You get the music and delivery views on every event — even one with no DJ attached yet. A tab that hides until a supplier exists reads as a missing feature rather than a missing supplier.
What each vendor is doing, for how long, for how much — recorded on the event, then turned into their contract. No separate thread per supplier.
What was planned against what's actually been spent, on the event itself rather than in a spreadsheet nobody opens after February.
Both of you pinning to the same board, so "the vibe" is a thing you can point at instead of a thread of screenshots.
Their guest count and their running order, read live from their own planner — not a copy you were emailed three weeks ago.
On the day
The timeline belongs to the event, not to each supplier. Move the first dance and it moves for the DJ, the photographer and the booth at the same time — which is the difference between a change and a rumour.
And Polaris answers from that same record in the room: who's giving toasts, what time the entrance is, who to ring when something slips.
Add them to the event and they see that event. They keep their own account, their own clients and their own business — you are not paying for their subscription and they are not looking at your book.
If a supplier isn't on Celestial yet, you can still create their leg and run the day from it. They're not a blocker for you.