A
AvaTax REST v2 API
Details
Authentication
Authorization: Basic <credential> For AvaTax REST integrations, sign in to your AvaTax account and use either your AvaTax username/password or your accountId:licenseKey pair as HTTP Basic credentials. Avalara's setup docs are Logins and Resources and Authentication in AvaTax REST v2. The easiest self-service path for API access is to retrieve your license key from the AvaTax web app as described in those docs.