Power Automate
Authentication
Set up API key authentication to connect SignatureAPI with Power Automate
Get your API Key
SignatureAPI actions and triggers in Power Automate authenticate using an API key.
If you haven’t already, sign up for a free SignatureAPI account.
To get your API key:
- Go to Dashboard > Settings > API Key.
- Click to copy your test API key.

Test vs Live Mode
Test API keys let you create envelopes for testing your flows. These envelopes:
- Don’t send real emails to recipients (but you can preview them in the Email section of your dashboard).
- Are not legally binding.
- Are free to use.
When you’re ready to send real, legally-binding envelopes, add a payment method and get a live API key. Envelopes created in live mode:
- Send actual emails to recipients.
- Are legally binding.
- Are billed.
Creating a Connection
The first time you add a SignatureAPI trigger or action in Power Automate, you’ll be asked to create a connection.

You can name the connection (for example, SignatureAPI Test or SignatureAPI Live), depending on which API key you’re using.