Is the transformation connected to a source or destination?
A transformation is always connected to a destination. RudderStack gives you the option to add a transformation while setting up a destination:
Can I connect multiple transformations to a destination?
No, it is not possible to connect multiple transformations to a destination. Instead, you can implement multiple use-cases in the same transformation, for example, event filtering followed by cleaning.
Can I write a transformation that can be applied to a small batch of events?
Yes, you can use the transformBatch function to apply a transformation to a batch of events.
Using the Event filtering, you can create and store a transformation or library as a draft without publishing them. These are called revisions.
Once the revisions meet the test criteria, you can restore and publish them for production use.
Device mode transformations
While sending events in device mode, how should I choose between event filtering and transformations?
You can choose any based on your requirements:
Event filtering: When you just want to filter out the events based on the event names. The event filtering takes place within the SDK and is only applicable for the track events.
Transformations: Transformations is a generic feature which can be used to manipulate the events, mask data, enrich events, implement specific actions on events. It involves a call to an external RudderStack service.
In case you plan to use both the above-mentioned features, your events will be filtered (based on the event filtering settings in the RudderStack dashboard) and transformed (based on the applied transformation) before being sent to the destination.
Is there any added performance cost to using the transformations in device mode?
Can I switch back to the previous version of an SDK while using a transformation in device mode?
For Mobile SDKs: Yes, you can switch back to the previous SDK version. However, the transformation might not be supported in the previous version.
If installed through RudderStack CDN, it’s not possible to downgrade the SDK version.
If installed through NPM, it’s possible to downgrade the SDK version. However, the transformation might not be supported in the previous version.
Will my event be lost in case of a network error while using a transformation in device mode?
No events are lost in case of mobile SDK’s as they are saved locally in the database before being sent to the destination. Once sent successfully, they’re removed from the database.
How does RudderStack test any library updates?
If you update a library that is referenced in any transformation, RudderStack tests the new library code along with the transformation code against the default event payload. This ensures that the transformation does not break due to any changes in the library.
RudderStack currently does not support testing libraries with custom events.
Can I test my library with sample events?
RudderStack currently does not support testing libraries with custom events. It provides a default payload against which you can test the library code along with any referenced transformations.
If you update a library, RudderStack tests the new library code along with the referenced transformation code. This ensures that the transformation does not break due to any changes in the library.
If you’re unable to update the library, it is likely that that the transformation is breaking because of the changes. Add the referenced transformation code and test the changes thoroughly.
What is a referenced library?
If a transformation Timports a libraryL in its code, then L is called as a referenced library to T.
I cannot import libraries into my existing transformations. What should I do?
If you cannot import libraries into your existing transformations, there is a strong likelihood that your existing transformations are based on the older version (Version: V0). To confirm if your transformation is based on an older version, check if your transformation has Version: V0:
To import the libraries in a transformation, follow these steps:
cookies, the cookies that are categorized as necessary are stored on your browser as they are as
for the working of basic functionalities of the website. We also use third-party cookies that
analyze and understand how you use this website. These cookies will be stored in your browser
consent. You also have the option to opt-out of these cookies. But opting out of some of these
have an effect on your browsing experience.
Necessary cookies are absolutely essential for the website to function properly. This
category only includes cookies that ensures basic functionalities and security
features of the website. These cookies do not store any personal information.
learn more about cookies and why we use them, visit our cookie
policy. We'll assume you're ok with this, but you can opt-out if you wish Cookie Settings.