Prismm sunset: what survives the Cvent migration

Prismm — the product most of us still call AllSeated — is being shut down by Cvent. It goes closed to new events since August 26, 2026 and closed for good in June 2027 on Cvent’s published timeline, with accounts moving into Cvent Event Diagramming. The official migration carries your recent events across, and that reassurance is doing a lot of work it hasn’t earned: your templates, favorites and object groups do not come with them, and nothing dated before January 1, 2022 comes at all. I’m Daniel Pitner, Director of Sales at EventDiagram, twelve-plus years in the event industry, and I sell one of the places you could land — disclosed properly in the next section. Everything here is from Cvent’s and Prismm’s own transition materials as of September 2, 2026, and I’ll update this post and its date as the deadlines pass.

Where I obviously stand

We build EventDiagram, and further down I describe what we’re offering people leaving Prismm — including a rate with a deadline on it. So read the recommendation section knowing exactly what I want. My defense is that the four sections before it contain no pitch at all: they’re the timeline, the migration table, and the honest case for staying with Cvent, which is the right answer for a good number of you. If you read only the first half of this post and act on it without ever hearing from me again, it will have done its job.

The three dates that matter

• Now through September 30, 2026 — new-event creation ends, account by account. This is the one people miss. It isn’t a single industry-wide switch; Cvent has been turning off new-event creation on a rolling basis. Your cutoff may already have passed while the headline date still reads October. Log in and try to create a test event — that is the only way to know where your account actually stands.
• August 26, 2026 — no new events. This date has passed. Existing events stay editable, but anything new is created in Cvent Event Diagramming, so every event on your calendar from here is being built somewhere else whether you chose that or not.
• June 2027 — Prismm access ends. Cvent’s migration page says your work stays view-only inside Cvent after that; whatever you didn’t export is stuck in someone else’s product.

Read those in order and the real deadline becomes obvious: it is not June 2027. It’s whenever your next event lands that you can no longer plan inside Prismm — for most people, that is already this month.

What survives the migration, and what silently doesn’t

This is the table I wish Cvent had published on one page. Everything in it comes from the transition materials, checked September 2, 2026:

Why “your events transferred” is the wrong reassurance

Here is the part that decides how much work this actually costs you, and it took me a beat to see it properly. An event and a template are not the same asset. The event is one night: a 180-guest wedding with that particular dance floor in that particular corner. The template is the machine that produced it — your ballroom, drawn correctly once, with the setups you sell built on top, so the next twenty events start from something true instead of from a blank rectangle.

The migration keeps the outputs and drops the machine. So a venue that has been on AllSeated since 2018 wakes up with a folder of individual layouts from 2022 onward and no reusable room. That’s not a data-loss problem you notice on migration day — it’s a problem you notice the first time someone asks for a proposal and there’s nothing to start from.

Which is why my advice to people staying inside Cvent is the same as my advice to people leaving: export your templates as PDFs well before the June 2027 sunset, even though a PDF is a flat picture. The picture is the reference a human rebuilds from, and it is the only version of your standard setups that will exist. The tactical version of this — seven things to export, in order — is in my Prismm export checklist, and it is deliberately written to be useful no matter which tool you choose.

Your three real options

1. Accept the migration into Cvent Event Diagramming

For a lot of organizations this is genuinely correct, and I’d rather say so than pretend otherwise. If you already run Cvent for registration or sourcing, the consolidation logic is real: one vendor, one login, an enormous venue library, and mature attendee management. The things to go in with your eyes open about are structural rather than technical — published tiers run $49 to $320 a month, every published tier below Enterprise includes exactly one user, paid plans carry a 12-month commitment, and the 150-attendee cap sits on Free, Standard and Pro alike. Price it against how many people on your team actually need to edit, because that is where the number moves.

2. Move to an independent tool

The case for leaving isn’t anger about the shutdown — it’s that you now have a forced rebuild either way. If your templates have to be recreated regardless, the switching cost that normally keeps people put has already been charged to you. That is the one moment when comparing tools is cheap, and it will not come around again. I keep an honest survey of every real Social Tables and Prismm alternative, with what each one charges, including the ones that beat us.

3. Run both through the transition

The one I’d actually recommend if you have the calendar for it. Let the migration happen — it costs you nothing to have your events land in Cvent — and rebuild one real upcoming event somewhere else in parallel. You will learn more in that one afternoon than from every comparison page on the internet, mine included. Then decide in November with evidence instead of in December under duress.

What we’re offering people leaving Prismm

Here is the pitch, clearly marked so you can skip it. We built this around the specific thing the migration takes from you — the rebuilt room — because that’s the actual cost, and because we do that work by hand anyway for venues we onboard.

• Free floor-plan import. Send us your Prismm or Social Tables exports and we rebuild them as editable, to-scale layouts — free during the transition window, however many rooms you have. This is the templates problem, solved by us instead of by your team at 10 PM.
• Pro free through January 31, 2027. The full toolkit — 3D, AI copilot, production library — free past Prismm’s shutdown date, with no card and no contract, so you can run real events before deciding anything. If you’re still paying an incumbent, we’ll credit up to three months on top, with proof.
• Founding Venue rate — $119 per property per month, locked 24 months. Venues that join before October 1, 2026 get the full Venue plan at $119 against a list price of $149, guaranteed for two years, with unlimited team members and monthly cancellation. That is our own deadline, not Cvent’s — Prismm itself stays editable until June 2027.
• Export-and-rollback guarantee. Your data leaves with you, any time, on any plan — in writing, in §10 of our Terms of Service, readable before you sign up. Given what you’re living through right now, I think you’re entitled to read the exit clause before the entry one.

The details, including how the conversion works and what we need from you, are on the Prismm migration page — or the AllSeated page if that’s still the name in your head (and if you want the whole arc from 2011 to here, I’ve written up what happened to AllSeated separately). Venues pricing this per property rather than per planner should start with the venue-side math; wedding planners, who made up a great deal of Prismm’s most loyal base, have their own page.

What to do this week

1. Log in and try to create a test event. If you can’t, your account is already past its cutoff and every date below is more urgent than you think.
2. Export your templates first, then pre-2022 events. Those are the two categories that do not survive in any form. Everything else has a second chance; these don’t.
3. Pull guest lists as CSV, not screenshots. Data re-imports. Pictures get retyped.
4. Ask Cvent in writing about any 3D you commissioned — what happens to it, and in what formats you can take it. Get the answer in email, not on a call.
5. Rebuild one real upcoming event somewhere before you commit anywhere. Including here. An hour with a room you know cold tells you what no comparison table can, and right now the rebuild is free whichever direction you go.

One last thing. In this industry the mistake is almost never choosing the wrong tool. It’s choosing in the last week, when the queue is long and the deadline is doing your thinking for you. You have four weeks before the first real door closes. That is enough time to decide well, and it is not enough time to procrastinate.