Due to multiple state-wide stay-at-home orders, the online event planning biz is seeing a massive spike in engagement for all sorts of get-togethers ... some more adult-friendly than others.

Evite made its name peddling online invitations, but has since become a go-to destination for online events. The company says it's seen a 1,130% increase in events tagged "virtual party" in the last year ... but it believes the lion's share of the boost has come in the last month.

We're told their biggest categories of online get-togethers of late include birthdays, cocktail parties and happy hours -- with average group sizes between 15 to 20.

Paperless Post -- another event planning company -- says in the past 12 days, virtual party events have jumped to 48% of their total biz. It used to be less than 1% ... so that's a clear quarantine-related shift.

As a result, PP's shifted to offer way more online invitation options -- for kids' birthday parties, game nights, book clubs, dance parties, brunch ... all the party possibilities.

Pretty amazing how quickly society adjusted. We've heard of workout groups, baby showers and even charity galas ... all moving to the online realm.

As you'd expect, in-person event planning is down, but not dead. We're told traditional invites for big stuff, mostly weddings, are still ordered -- but by and large event planners are marketing for online biz now.

Evolve or die.