Say hello to iOS Health team at Monzo 🍎 🩺

I’m on TF and don’t have this issue


I just can’t get over this image, 6Gb is insane



Lucky me, had this account for two years

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I’m experiencing a bug with Summary. I’m seeing my personal Summary screen on my joint account. When I view a transaction from the Joint Summary it shows my personal transactions. Done the usual delete and reinstall. Still there.

Hi @Paulw, thanks for the report.

I’ve highlighted this to the team but we need some more details to be able to reproduce it. If you are using a beta version though Testflight could you report the issue through Testflight? From there we automatically get extra info to help us. If not could you follow the requirements in this thread so you know what info we require.

Just to reiterate what @leewatkins said towards the top of this thread; the iOS health team is primarily focused on stability, logouts & performance for now. The excessive data usage does fall under our umbrella but the bugs on specific screens belong to separate teams. If a bug seems to be tied to a specific screen on the app then it’s best to report it in the bug reports section of the community for now so it doesn’t get lost in the middle of a thread.

Thanks - Dale


Thanks Dale for the clarification :slightly_smiling_face:

Only me who noticed the low resolution assets used within the iOS app at least?

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The new overview screen in Monzo Labs, when active. It’s not sending me notifications when I receive money? Someone paid me this morning and I wouldn’t have known if they didn’t message me

Hi Dale, any update on the large data size issue on iOS devices? My device is still showing 3.56GB data for Monzo. I haven’t tried uninstalling and re-installing.


We conducted an initial investigation but have yet to find the root cause of the issue. We have a couple of higher priority issues to address first and then we will be back to looking at this, but it looks like it’s going to take some time. We update you as soon as we have something to share.

Thanks for the report, I have forwarded this to the relevant team.


I just want to give an ‘update about the update’.

Due to the low level nature of some of the issues we have been addressing we are being very cautious with how we roll them out. Some of the issues required us to take our time gathering concrete evidence (sometimes over multiple weekly releases) and then more time prove the fixes we have put in place have actually worked. All of this has led us to take a little longer to put something tangible together for the community.

We have some very exciting things we are working on and have recently had a couple of ‘aha’ moments. But rest assured the needle is moving in the right direction and as with a lot of our work right now, we just need a little more time. Thanks for you patience!


Thanks for stopping by @DaleBuckley and giving us an update :smiley: I look forward to seeing what things you’ve been tweaking when we get to that point!


Hey folks! :wave:t2:

As promised, here’s an update on what iOS Health has been up to over the last three-ish months!

You’ll notice a common theme through all of the updates below: a process of gather data, visualise, understand and then fix. We’ve had to spend a lot of time over the first few months just getting a clear picture of where the biggest issues are, what’s causing them, and then making sure that our fixes are working and not doing any harm.


We’ve put together a list of our top crashes, and built out a lovely set of graphs that help us track each of these. We’ve been focused on the top 10 crashes, and we’ve largely eliminated 5/10. These include problems with how we save data to the phone, how we convert HTML into content on screen in the app, how to store account information when users are updating their address and how we talk to our backend when we have lots of info to transfer at the same time.

You’ll also be happy to know that we think we’ve found a fixed one of the biggest background crashes…so those TestFlight users who see the alert telling you that Monzo has crashes in the background, keep your eyes peeled for v5.20.0, and let’s hope that we have indeed found that bug and squashed it :crossed_fingers:t2:. It won’t fix all the background crashes, but it should fix the most common one!

Here are a few graphs to show the drastic decline in numbers as we’ve shipped the fixes:


We’ve been working really hard to understand why users are being logged out of the app when they shouldn’t be. We found that we were having some problems with how we save & read data from the phone in specific cases. When the app launched it wasn’t able to read the user’s info, and so we treated the user as logged out.

We had to make some significant changes to how we monitor these problems so that we see what was happening, and that took a while to build and ship, but we now have a bunch more info on this problem.

We still aren’t 100% sure why those specific cases are causing problems, but we have a few hypotheses, and we’ve made changes to test those ideas out and validate whether they fix the problem.

In addition to that, we’re busy implementing a self-recovery mechanism, so that when users get into this strange logged-out state, the app can auto-recover, without the user having to log in again.


We’ve started taking a look at app launch times. We’ve put in a bunch of measurements to understand how long each part of the app launch takes so that we can look to optimise it. Once again, reading data stored on the phone is one of the slowest processes, so we’re looking at how we might speed that up. More info on that will follow in the coming weeks.

We have also started looking at excessive disk usage and are about to start testing a database update which should help with cleaning up old/redundant data. We aren’t at the point where we can measure how much of a difference this will make and are continuing with our investigations, but small ‘low hanging fruit’ improvements in this area will start shipping in the next few releases while we dig further. If you see any drastic changes in this area for the better or for the worse then please reach out.


Over the last few months we’ve managed to reduce the total number of crashes by 34%, while the number of folks using the app has grown by 7%. So even though app usage has increased, crashes have drastically decreased. We’re hoping that the logouts number start to improve over the next month, and that performance can follow on after that.

Lastly, we just want to say a huge thank you for all of your support - the encouragement has been really motivating, and you’ve given loads of help identifying and debugging some of the issues that we’ve had. :pray:t2:


:heart_eyes::heart_eyes: downward falling graphs.

Thanks for the huge update, really appreciate and I’ll keep my eyes peeled for the updated TF version!

Are some of the issues you’re facing in slow times reading data from the phone more prevalent in older devices, or is it something that’s seen across all of them?

Really loving the huge write up, and taking the time to update us. :heart:


It does affect all devices but it’s more apparent in older devices. To give you an idea; we are seeing data loading/migration times (depending on the complexity of any data migration being performed) around 0.3 seconds for newer devices but it can take several seconds on older devices. 0.3 seconds might not see like much but it’s only one part of the overall launch process (loading/initialising critical systems, rendering UI etc.).

It’s worth keeping in mind there are many contributing factors which can affect the times, even on newer devices. For example we are seeing newer devices running iOS 17 pop up in our logs now (probably from Apple engineers running alpha versions of the soon to be announced OS). From those logs we are seeing notable increases in loading time on those devices most likely due to all of the extra debugging code which is added to the OS during early stages of development. We can only speculate on this particular set of users for now, but we have noted it as something to keep an eye on.

The benefit now is we have more fine grained visibility on whats actually going on over the entire launch process where as previously we only had a rough idea. This will help inform us where we are making gains and also give us early visibility on any possible issues so we can address them quickly. As @leewatkins mentioned earlier, this is part of our “understanding, fixing, monitoring” strategy.

Friday fun fact! Across our users we currently have >1821 permutations of device/iOS versions from iOS 13 and iPhone 6S and up! This is only set to grow once the iOS 17 betas get released on June 5th.


:eyes: :eyes:


Wonder if that’s UK or US users

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I would love to go < Bac