Importing offline conversion data into Firebase Analytics

[Sushil Choudhari]

Hello, 

I am looking for ways to import offline conversions into Firebase Analytics. My app is a shopping aggregator to discover deals and coupons from online retailers. User is then redirected to merchant app or website for completing the transaction ( external to my app/website). I get offline reports from retailors everyday day about confirmed transactions. 

How can i import this offline transaction data into Firebase analytics, such that i can see funnels and segmentation for these transacting users in analytics UI?

Google Analytics supports multiple ways of importing offline conversions:

https://ga-dev-tools.appspot.com/hit-builder/ hitbuilder

https://developers.google.com/analytics/devguides/collection/protocol/v1/

https://www.en.advertisercommunity.com/t5/Google-Analytics-Tracking-Goals/Import-Offline-Conversions-in-GA/td-p/557400#

What is the counterpart of these tools in Firebase Analytics?

Thanks in advance.