How we accidentally broke our Android notification sounds (and fixed them!)

We recently encountered an interesting bug in our Android app notifications – engineer Jonathon explains what happened and how we fixed it!


Thanks for the update but any chance it could be translated into English :joy::joy::joy:

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Imagine you’ve got 5 CDs, each plays a different sound.

They are numbered in order, 1-5

Someone comes along and puts a new CD in at #2.

The old 2 becomes 3, 3 becomes 4 etc.

So now you have 1-6.

Anyone who didn’t get told the numbers changed will now play the wrong CD when asked to play #3.

The notifications work the same way with references to the sounds in alphabetical order. If you put new sounds in early on, it messes up the old order.


I feel famous now :joy:, being featured on the Monzo blog!


RIP Emma :pleading_face: :bouquet:

It was amusing so sad to see it go, but I do love a good technical write-up though :nerd_face:

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You said the cds were numbered so 3 is still 3 :wink:

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What are CDs?

Kidding :wink: :laughing:


It would be good if we could choose our own sounds, I did read in the ifttt post somewhere that I guy had managed to get ‘hey big spender’ by Shirley B play as his sound for when he spent over £100. I did try to recreate it but failed…:frowning:

Personalisation and customisation are the way forward. :l

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My mind is racing with ideas now :exploding_head: I now need this functionality in my life! :laughing:

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I’d love ‘I just got paid’ to be belted out when my wage hits my account… :slight_smile:

Don’t even get me started on movie references that you could use too :pleading_face:

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That idea sounds great… until you’re woken up at 2am (or whatever time it is) when direct debits come in :joy:

Can’t you go via Monzo -> App Info -> Notifications -> Cog (adjacent to “Account debited”) -> Behaviour -> Make sound and then pick a Sound instead of using the app-provided sound?

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Actually love it when companies break things… and come clean about it.

Makes me trust them even more!

Great job Monzo <3

Is this an IOS thing?

Where is App info in the Monzo app :confused:

It’s an android thing. It’s via the manage apps interface, but you can only change the sound for all notification for a single channel.

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I reported this bug with the chat function in the app on the 4th of may, they wanted me to reinstall the app but I couldn’t be bothered, glad it’s fixed.

The next notification bug I’ve noticed is that Monzo keeps muting itself, showing notifications silently rather than alerting me. I’ve changed it back to alert me but every so often it goes back to show silently. Maybe this is after the app updates I’m not sure. I’m on Android Q so that could be related.

@bea Can we have more of these engineer posts please. Not just bugs but nifty solutions to problems are interesting to hear too.

Maybe full technical then a short simplied if possible so everyone can join in like @Ganey CD explanation


If only they could fix it so the app itself on iOS stops making the notification sounds, even when you have sounds in notifications settings turned off…

Engineer Jonathon - finally someone with the same awkward spelling like me :slight_smile: