Your API requests are authenticated an API token generated in your ZipMessage. Any request that doesn't include an API token will return an error.
You can generate an API token in your ZipMessage account in Settings > Integrations > API tokens
ZipMessage expects your API token to be included in all API requests in a header that looks like the following:
Replace zipmessage_api_token with the API token found in your account.
The ZipMessage API endpoints are made available to accounts that have an active subscription to a plan that allows for API access. Refer to the ZipMessage pricing tiers to confirm the plan level required to access.
If a request is made with a valid API token but the associated account is unauthorized for API access, it will return a 403 error:
"error": "This account needs to upgrade in order to access the API."