How does Postman generate oAuth 1.0a signatures?

Question

I'm attempting to connect to an oAuth 1.0 authenticated endpoint but the signature that Postman creates does not match the signature we expect in our code. As far as I can see all the parameters that I have added are correct (Url, consumer_key, consumer_secret, nonce, timestamp, HMAC-SHA1) but Postman just seems to generate a different signature with these details. Does anyone know how Postman creates the signature?

Demise

When I use postman, I get a success message from the API I'm calling. My guess is a HASH of the URL I'm calling, then HMAC_SHA1 of that results in signature in hex format? – Thorwald

Not sure if you already figured out the answer to this question, but you could try grabbing the raw curl command that Postman generates to see if the signature looks as expected. To get the curl command for any given endpoint you can simply click on Code underneath the Save button. – Teleology