Multiple parameters on custom events

Hi everyone,

Today we’re excited to launch a new feature that should improve modularity on Bubble, thereby making it faster and more productive to use our language – multiple parameters on custom events! Shoutout to @alex.stanescu for building this out!

Previously, you could only define one parameter (type of thing) on custom events. With this new feature, you’ll be able to define multiple parameters using a name and data type, similar to how you define parameters in API workflows, on both page and backend custom events. In addition, you can specify whether the parameter is a list/array or optional. To learn more about this feature, please refer to our documentation here.

You’ll then be able to use these parameters as data sources in the custom event’s actions.

When you use actions that include custom events, you will be able to specify the data that gets passed through the event as a parameter.

This feature should be helpful in allowing you to use multiple parameters to edit elements, rather than using workarounds like custom states. Further, multiple parameters are no longer limited to API workflows (which are only included on paid plans and run async)! We hope multiple parameters on custom events unlock more powerful capabilities for our users, from beginners starting on our free plan to experts navigating through complex functionality 🙂

Looking forward to hearing your feedback on this new feature!


Hey @grace.hong

Nice one. I´ve just seen that the previous created custom events show “_LEGACY”.

Is that ok?

Thank a lot.

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Good question @ryanck! In order to make this new feature backwards-compatible, we renamed the single existing parameter for custom events to “LEGACY” (since users previously did not choose a name for the parameter). You can feel free to rename the parameter whatever you’d like :slight_smile:


That’s a really great improvement!

Lots of things moving in the right direction at the moment, it’s nice to be part of it!

Have a great weekend


This is great! Thanks @grace.hong

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splendid. this is a life saver! now we can create reusable workflows for a lot more complex fucntions. Thanks !


This is amazing!! thank you team!

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Wow, this is awesome and was one of my suggestions on the Ideaboard. Thanks!


Same here! I love this! Unlocks so much functionality for me – No more having to create endless custom states just to hold this info for custom workflows. Thank you @grace.hong and Bubble squad :slight_smile:

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  • +1: :+1: :+1: This will be very helpful. No more error-prone workarounds needed to achieve this.

Holy mother bear! This changes everything!

…well, ok, maybe not everything, but lots of things.



Optional parameters too! Great stuff :+1: :grinning:

Being a bit cheeky but … if we could just get them to return a value … that’d be great :blush:


Actually, this would be the next piece… returned value from custom event.


Quick update - for users who haven’t yet opened their editor, we’re changing the name we automatically generate for existing custom events from “LEGACY” to “Workflow’s [data type]” as to provide more clarity (and hopefully less work/time spent on renaming parameters). This shouldn’t impact anything, but just wanted to provide a head’s up.


This is great, thank you!

Hey !

This actually killed a key feature of my website in LIVE. WTF ?:

And, it when trying to update, it actually say the parameter is empty when passed (in dev here):

Need a fix ASAP


Backend / custom workflows stopped working on live after this update. Really, really critical this gets fixed ASAP. It’s affecting most of the application. Already submitted a bug report.


Gotcha, we’re looking into this right now. If you haven’t already, could you please submit a bug report so we can reproduce the behavior on your app: Bug Report | Bubble


Will do, will need to know when this is solved, my Bubble app is actually broken due to that


I think I’ve narrowed this down to an issue with parameters being sent from one custom event to another. Sending parameters from other workflows looks like it’s working.

This has also bricked my site, hoping you can fix asap!

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