Hi! Yes, I have great news!
Right now the new version of NativeRest 2.6.2 is available. I just finished the necessary release notes and wanted to write to you.
Now you need to use the new hmac.sha256 function to fill in the Signature header.
This function has 2 parameters: Data, Key.
In the first - payload, and in the second - secret.
Signature: {{hmac.sha256({{payload}},{{secret}})}}

This is a continuation of my answer:
In my example, 2 parameters are declared payload and secret, in which the values ​​are written:
payload = /public/api/ver1/users/change_mode?mode=paper
secret = NhqPtmdSJYdKjVHj...
In my opinion, variables are more convenient, but it is not necessary to use them.

See an example of using hmac.sha256 in NativeRest in this screenshot:
https://nativesoft.com/static/images/using-hmac-sha256-function.png

Awesome, thank you! I made a GET request successfully using your new feature!
I will let you know if I have further issues.

But have a comment about the Mac app. I don't think the shortcuts are very logical.
1. I wonder why for the duplication, why do you have to add shift to every keyboard shortcut?
2. also when you tap around to select words, you use very weird keys for the Mac.

Continued... Mac uses option/alt+arrow left/right to jump between words. You use command+shift+arrow left/right to select the whole line. And most importantly, you use shift+alt+arrow left/right to select a word. This is not how it works in Native Rest. So it feels quite unintuitive when working on a Mac. I hope this can be fixed in the Mac version. Check app on Mac to see (TextEdit, browsers etc)

Finally I wonder if it's possible to get this work in a way where I don't have to specify the endpoint twice. Because right now I have to specify the endpoint path in the variables. And continuously update this, it could be nice if it would simply take the endpoint path from the URL bar. Then I could insert that variable in the signature generation.

In addition, whenever I work on a new request, I have to go back and update the workspace variable to use a different payload for every request since the payload is not part of the request itself, but part of the workspace variables. So I can't really keep multiple requests open in a working state, it seems, because the payload variable I have to set each time - it is not saved with the request.

Hi! 👋 Thank you for these suggestions and comments. 🙌
1. I'll take another look at the standard hotkeys for working with text in macOS and try to improve this in NativeRest.
2. Please try the variable {{request.uri.path}} – it returns the path (/public/api/ver1/users/change_mode). For example:
Signature: {{hmac.sha256({{request.uri.path}}?mode=paper,{{secret}})}}

Would you like a new {{request.body}} variable to get the request body for use in headers?
If you prefer, you can write to me at support@nativesoft.com. The message length limit here is too small for our discussion. 😆