The proper word is "invitation".

I thought so too until I checked, but the references I cite above say 'an invite' has also been used since the 17th century, at least for US English.

"an invite" is not specifically techspeak because it's widely used outside tech (esp. in US English), unlike "an ask".

Dictionaries say "an invite" has been used as a noun for centuries.

[0]: https://www.merriam-webster.com/grammar/can-you-use-invite-a...

[1]: https://english.stackexchange.com/questions/68937/invite-vs-...