The issue with doing that on some services (like paying off your Amex bill in the app), is that as soon as you leave the app, it disconnects the transaction.
So by the time you’ve “authorised” the 3DS element in your Monzo app, Amex have cancelled the transaction - This is why Monzo force the SMS option on some services.
It also means that if you’re travelling and using a different SIM, you can’t make purchases requiring 3DS. 
(I get why there are use cases where people prefer SMS, but having it as the only option is limiting.)
Can’t see that they do, but do Starling have referral codes? Going to sign up as a back up for when abroad
You can use mine:
2FTJWXGX https://www.starlingbank.com/referral/?token=2FTJWXGX
Starling’s Chief Financial Officer is off in around 18 months time - succession planning underway:
https://www.ft.com/content/af02432a-5d3e-11e9-939a-341f5ada9d40
Is it possible to pay in euros cash via the post office to your euro account?
I doubt it… but this would be very handy if so 
No euro account here yet 
By the way, do you get a card for the euro account and/or if I use my normal Starling card for a euro transaction, will it use the euro balance instead?
No card for the account yet.
Currently, if you use your card for a Euro transaction, it’ll still come from your GBP balance.
Can’t remember the last update, but I believe the plan is to use the one card (in the way you’ve described), rather than having 2 cards.
The teal didn’t last long 
.
This has just killed Revolut for me. I prefered them over Transferwise. I can now easily ‘without fees’ convert to Euro and transfer to my KBC Ireland Euro bank account.
Starling has just taken over as my spending account from N26 as of today. If multiple GBP personal accounts are launched or they fix my niggling bug, I may switch fully from Monzo.
Just be aware that you can’t move money into your Starling Euro account at all during the weekend (obviously Revolut are expensive at the weekend, but if you were desperate, you can).
But I agree, for what I was using Revolut for, Starling have replaced them (the odd time I’d need to make a Euro transfer), and I just feel much more comfortable with Starling!
Planning one card two currencies (or maybe three if they launch somewhere else) still waiting though!
Does Starling have the ability to move money in and out of a goal/pot automatically like IFTTT and does it have roundups and can you do 1p challenge etc?
It has roundups, and you can put a multiplier on roundups by x2, x5 and x10 too - a feature many on here have requested Monzo add.
I’m not sure about the IFTTT-like integration, because I have no experience with IFTTT yet, but in theory it should be possible.
I don’t think theory comes into play here. They’ve either created/approved an integration or they haven’t.
In either case, it looks like they haven’t and currently have no plans to.
