How can I connect and consume a Kinesis data stream from a different AWS account in your AWS account Firehose, which then processes the data and stores it in S3,

Hi,

I understand you are sending data from Kinesis Stream in one account to Amazon Data Firehose in another account.

Kinesis Stream (in Account A) -> Firehose (in Account B)

Unfortunately, this is not supported at the moment. You can maybe use Lambda as workaround you may consider having lambda function for your use case.

kinesis stream (Account A) --> lambda (Account A) -->Data Firehose (Account B)

You can follow below document to create kinesis trigger for lambda function : kinesis stream (Account A) --> lambda (Account A)

[+] Using AWS Lambda with Amazon Kinesis - Configuring a stream as an event source - https://docs.aws.amazon.com/lambda/latest/dg/with-kinesis.html#services-kinesis-eventsourcemapping

Further, you have to write code in lambda that push the records to firehose stream : lambda (Account A) --> Data Firehose (Account B)

you can refer to the below third party article to get some idea about how it can be done.

https://faun.pub/quicksolutions-cross-account-use-lambda-to-write-to-firehose-in-another-aws-account-38bc4270a348