iOS App Slowdown & Lag


I’ve been in very rural parts of the UK for 4 days or so. I reported the slow down reported in this thread whilst I was in a big city but it got much worse when my network speed slowed down out in the countryside. I had 3G but I imagine a very weak version of it. Many other apps worked ok in these conditions though. I reinstalled the Monzo app as requested but it made no difference. You can see as you scroll up and down the iOS data spinner going and the feed getting stuck. It appears to be fetching lots of data and I conclude from this that there isn’t much caching within the app. Also I had a time where the balance wouldn’t update at all from £0 even though the app had known it previously. It’s a shame the app doesn’t remember the last balance relating to the last transaction seen. Fetching it every time might be an easy implementation choice with users on low latency networks but it’s pretty bad on a high latency network. The app wasn’t very usable.



I’m on iphone 8 and no issues with performance. A number of factors can affect performance besides the app but given the number of responses on here seems that the app itself is responsible. One thing I note with the iphone coming from android is that it will keep open a lot of apps with no crashes but this can impact app speed so worth killing them off then opening Monzo (double click the home button and swipe). I’d also be interested in whether this is on mobile or wi-fi, free space and iphone versions and that of the ios as there may be a common dominator.

(Andy) #86

Hi @MeganV :wave: just be aware that killing apps on iOS is completely unnecessary and can drain your battery faster. It’s far more efficient to let iOS manage your system resources. Than removing the apps from the app switcher. Also killing Monzo means you can’t take advantage of location based security features


I’m running 11.4.1 and have noticed all the problems mentioned in the thread.

Unlocking and black screen, unresponsive for a few moments.

Click on payments and wait, then it opens, want to go back to summary so I click it, and again wait for it to open.

Even updating my balance or showing my latest transactions isn’t quick anymore, and I have an excellent ping rate with my isp.

The account section, to me is the slowest. I’m swiping away trying to look at a pot and it takes several attempts and a few seconds before it becomes responsive.

Every other app on my phone is fine. It’s definitely only Monzo


This is true, but there is still quite a substantial lag for me either way. Leaving the app open or starting from cold (as you say and makes sense). I’ve even deleted the app and re downloaded. Make no difference.

(Caspar Aremi) #92

It feels like it’s getting worse - trying to get into my account page, and scroll to pots, can take quite a long time. Could it be related to the large numbers of transaction history if it’s mostly those of us who have been using Monzo for a longer time?


I’m not an expert an ios but as a network engineer I know that feature rich content can cause web pages to slow down (if you use Chrome you can use developers tools to see this) so it would make sense. It could equally be a coding issue or device related. Do you have a lot of free space on your iphone or is it nearly full?

(Caspar Aremi) #94

Loads of space - its a 128gb phone with over 40gb still free.


Hi. Sorry I think you are incorrect. Location based security can be set to when the app is in use or always. If as mine is, it’s always then security is not affected. Leaving apps open will not only drain battery but potentially use data and can be a security risk depending on the app as data will be visible and can be reopened without using the normal login verification. Monzo may not be affected but leaving apps running is not good practice.

(Justin) #96

I began noticing the issue around three weeks ago, in the TestFlight app. My first concern was that something in the new app had caused performance to deteriorate, but when I deleted and then reinstalled the App Store version, I had the same problem: when initially opened, the transaction history freezes for a couple of seconds, and then scrolling tends to stutter.

My second thought was that this might be due to the high number of transactions I’d accumulated over the past 2.5 years (over 2,200!) - and that perhaps the app’s performance deteriorated exponentially as the size of the table increased.

I raised it with the Support team, who suggested I delete and reinstall the app - but I’d already done that, so it didn’t help. It does feel to me like a genuine issue that requires resolving.

I’m using an iPhone X with 256 GB - and over 20GB free.

(Dan) #97

I’m afraid this isn’t true - talking specifically iOS here. Memory management on iOS is really clever, and looks after itself to optimise CPU, memory (RAM), battery life and storage.

For those not technically inclined, you can imagine RAM as a snapshot of an apps current state. It contains words, images, layouts that an app will reference to run smoothly etc.

When you have an app in the foreground, it actively runs, and can process tasks that use the CPU/RAM. This uses the battery.

When you click the home button, iOS quickly takes the app’s state from the RAM and put’s it into storage (and removes most of it from RAM). From that point, the app itself doesn’t call any of it’s usual code, and so doesn’t use the battery.
This happens in reverse when you reopen the app. The flash memory is super fast. it can load the apps old state and iOS injects that back into RAM before the animation of the app opening even finishes (most of the time :smirk:)

iOS over time has included more and more specific actions a background app is allowed to run. These are run by the OS itself rather than the app. These include background location services, playing music, receiving phone calls etc. Having background apps can consume extra battery, for instance an app continuously requesting your location, but iOS manages this intelligently. If 3 apps regularly request your loc, iOS will only actually locate you once, and give each app the same loc, saving 2 further requests.

When you fully close down an app and reopen it, iOS has to read a lot of fresh information about the app and load that into RAM. Depending on the app, it might be a bit excessive to do this repeatedly.

Really, I would just recommend you leave iOS to manage it’s own resources. Fully killing apps is useful if there’s a bug with the app or if you have genuine concern that an app is killing your battery and you need it (like leaving Uber to do it’s thing when you’re in 10% :nauseated_face:).

tl;dr it is definitely not bad practice to leave apps running. iOS looks after itself pretty well. Killing apps is usually unnecessary.

(Andy) #98

Thanks @danbeddows said it a lot better than I would have :joy:


Basically what @danbeddows said is a very good concise argument for leaving apps open.

But you can also google it, and receive the same info everywhere.

For instance…


Cool, basically what I said - but a bunch of my comments got deleted for some reason :+1:

(Charles de Dreuille) #102

Since the last update yesterday it’s getting worse. When I try to click on the account tab once, most of the time it will wait 1 or 2 sec and then trigger the menu to switch to joint account even if I didn’t do a long press.

I also have to wait longer than before to see my list of friends leaving me with a illustration that I have no friends :couple:.

(MikeF) #103

No comments removed from this thread :+1:and comments are never deleted.

(You’d see the little telltale messages if either had happened).


Oh weird - there’s at least 2 of mine that have entirely disappeared from the thread for me, along with one from someone else that i was replying to.

I know what you mean by the telltale messages, so this is an odd one.

(Andy) #105

Without wanting to go too far off topic I’m sure I remember seeing responses by you on this as well but as @Feathers there’s been no removed posts :face_with_monocle:


Yep, you even hearted them. I guess Discourse had a bit of a tantrum and threw a few posts out of the pram.

(Glenn Lewis) #107

I used to work for Apple. Force quitting apps should only be done when an app isn’t working correctly. Doing it regularly will drain your battery very quickly. :grinning: