Showing results for 
Search instead for 
Did you mean: 
Level: Powered On

Connect to Amazon S3



I'm trying to connect Amazon S3 creating a custom connector with the REST API they provide. 

The problem is that is necessary to generate a signature based in the API key and other values. The signature is valid for 7 days, so it not possible to generate once outside - it would be pointless to generate a process that aims to be automatic needing a manual input.


Is there a way to generate HMAC signatures in a custom connector for Microsoft Flow?


If the connection is not Oauth 2.0, the custom connector is extremely rigid in the options they provide.


Is there any solution that doesn't involve using Azure Functions? 

Community Support Team
Community Support Team

Re: Connect to Amazon S3

Hi @acanepaecon,


It seems that you have created a custom connector to Amazon S3 using REST API.


Here is a doc on Amazon S3 REST API Introduction, hope it could be a reference for you:


While Oauth 2.0 is required when registering Custom API, please check the following docs for more details:



Best regards,

Mabel Mao

Community Support Team _ Mabel Mao
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Level: Powered On

Re: Connect to Amazon S3

Hi @v-yamao-msft,


Seems like you didn't read my message, I've already read those. The problem relies on the creation of a signature, that's where the problem is.

It will be cool to generate the signature inside flow, as a custom connector.



Level 8

Re: Connect to Amazon S3

I’ve been thinking about how to tackle this issue as well. My issue is slightly different, I need to generate an AWS signature v4 to pass in a header to AWS API gateway. Flow and logic apps seem to have no native Authenticaton options for AWS which is a shame. The only way I’ve thought on how to do this is put an Azure function http trigger in front of the AWS api gateway, and have it use oauth or something that flow CAN talk to and have the Azure function contain the logic to build the aws signature to then pass to AWS. Not elegant but no other option? It would be great to have AWS connectors in flow for s3, dynamodb, etc
Level: Powered On

Re: Connect to Amazon S3

The API appraoch with S3 buckets is way too painful/complex and slow. I found a workaround.   Use the SFTP-as-a-service that connects to S3  then use the SFTP action in Flow 🙂

Helpful resources


Power Automate Community User Group Member Badge

Fill out a quick form to claim your user group badge now!


Incoming: New and improved badges!

We've given our badges an overhaul and also added some brand new ones!


Microsoft Learn

Learn how to build the business apps that you need.


Power Platform World Tour

Find out where you can attend!


Webinars & Video Gallery

Watch & learn from the Power Automate Community Video Gallery!

Top Kudoed Authors
Users Online
Currently online: 176 members 6,262 guests
Please welcome our newest community members: