To be completely fair to Monzo though, my limited understanding is that this reliance on a 'supplier' for payments will go away when the beta ends and Monzo's a full-fledged bank/current account, rather than just a prepaid card.
EDIT: ^ That was correct, that is the intention: 
> When we launch the current account later this year, it will not use a third-party card processor and instead transactions will be processed entirely on our own technology.
 - https://monzo.com/blog/2017/03/05/outage/
Edit: My mistake, its GPS doing the processing -- who are currently experiencing issues.
They are, I just updated my top-level comment - they confirm that in the blog post the CTO linked in another comment here: https://monzo.com/blog/2017/03/05/outage/
And if it does happen, the nature of how they operate means it should be significantly faster to resolve. Particularly because there is no reliance on a third party
If anything, a small startups who has to redo everything from scratch with limited resources seems like there is huge room for errors, and not many people to support and fix them 24/7.
Their systems are incredibly stable. In fact, I don't think I can recall a single bit of downtime which was actually down to their system since November 2015 when I joined.
In the case which happened here, some kind of unexpected migration gone wrong - Monzo's systems are highly decoupled and separated. So any given database issue will only affect that given service. As each service is so simple and contains relatively little code, working towards a resolution can be achieved significantly faster. The smaller scope of responsibility also means that a mistake is less likely to happen in the first place.
Downtime is downtime.
Ignoring and shifting the blame to third parties will not fly with customers who are unable to buy their groceries. Just saying ;)
Would have really appreciated a push notification as soon as the issue occurred -- they sent one a few hours too late.
If you're running a critical service, please make sure you have an appropriate and working notification strategy for major failures.
One of the things we have learned from this incident is to proactively reach out to all customers as early as possible, even if it means alarming a large number of people.
We did tweet about the incident and updated our statuspage the moment we discovered it, but we didn't proactively message all customers until a few hours later.
What would that be then? This outage is not Monzo's, but the processor's, affecting any card issuer that users it - a function Monzo has stated  it will do for itself without a third-party when it offers full current accounts later this year.
Calling this Monzo's failing is like complaining that Trello went down earlier in the week (due to the S3 outage). It's perhaps even less fair, since I imagine using multiple AWS regions is easier and more common practice than using multiple card payments processors. (Though I am just speculating on the latter point.)
No offense but I am gonna stay with my current bank ;)
When Monzo is actually capable of replacing your present bank, i.e. it offers current accounts, this issue won't exist.
> current accounts should be held to the same standards as an average todo-list app?
If your present bank used the same card payments processor, it would be experiencing the same outage. That's my point, not that it doesn't require more stringent certification than Trello.
> So you are saying that my credit cards and
There's no credit cards and the company's stated no plans to ever offer any, preferring to instead ask What problem makes you seek a credit card, and rethink what a modern solution looks like.
> No offense ... ;)
Why would I take offence? I'm just a user, no skin off my back if you're not ;)
(Oh and quick note to Jonas, the iOS app did not push any notifications whatsoever...)
Also from the status page:
If you have incurred FX fees because you were unable to use your Monzo card, we will reimburse you for those fees. Please get in touch once this issue has been resolved.
I've (accidentally) had a free dinner once when I used a locked prepaid card and neither me or the staff behind the bar noticed that it declined.
It's right up there with all the companies that stress how "your security is our highest priority", right after they get compromised.
which processor do they all use?