1. Create a test key
Open Dashboard > API keys, choose the Test environment, and create a key.
The raw key is displayed once and begins with sg_test_.
Store the key in a secret manager as soon as it is created. SignupBear stores a
SHA-256 hash and cannot show the raw key again.
2. Add the key to your server
Do not prefix this value with Bearer; add that only in the HTTP header.
3. Check an email
4. Enforce the decision
Start with the deterministic addresses in Test mode, then
switch to an sg_live_ key when your error handling and monitoring are ready.