Tacky or fun to include a qr code with wedding invitation?

Nothing should be on the back of the invitation. If you need to give extra info, you include the insert cards.

The qr thing really depends on your crowd. Some people use them and others don’t.

This is super nifty, but may be off putting for older guests. Depending on your crowd, I'd include this as an addition to a regular rsvp card that guests can send back

If you want to include it, do so on a separate enclosure card and not on the invitation. I don't think it's tacky, but it's certainly a "know your crowd" situation. If you have a good amount of older guests, a QR code may be confusing. If it's mostly younger people, then it could be a convenient thing. And then there's the matter of available technology and general preferences. In my case, my phone absolutely will not scan a QR code. You may have guests that are in that situation as well. And some people would prefer to use a computer to look at a wedding website because they find that to be a more pleasant experience than trying to navigate it on the smaller screen of a phone. Then again, some people would prefer to just whip out their phone and be able to quickly get to the wedding website instead of having to type in the web address (whether on a phone or a computer). There are a lot of variables, but I don't think having that code to scan would be bad. If the idea is to get people to visit the wedding website in general, I'd suggest having the code take them to the homepage of the website instead of the RSVP page. They can find the RSVP page easily enough and if they're brought there directly they might not even look at the rest of the website.

I don't think its tacky, but I also don't think QR codes really save much time/effort if the URL to your wedding website is fairly short and uncomplicated, and it may only confuse or frustrate some guests. Most of your guests will be able to figure out how to type in a URL, far less have the capability or know how to use a QR code effectively and there is absolutely no one who is going to be able to use the QR code who wouldn't be able to just typer your URL into a web browser. If you had a website URL that was a random combination of numbers and letters, I would say go for it, but in this case I think its clunky, unnecessary, and likely doesn't add anything.

I think this is brilliant! Can they RSVP through this too? Especially after covid, if anyone has gone out to eat these aren't foreign anymore. I don't know if its tacky or not but i'm absolutely doing this!

It's not against etiquette to do a QR code. As said earlier, nothing should be on the back of the invitation though. I'd just use an insert card.