Do you have an API?

Yes, we do have an API. We call it the Seal Subscriptions Merchant API and it allows you to retrieve info about your subscriptions and set up various webhooks.
You can view the documentation for the API here: https://www.sealsubscriptions.com/articles/merchant-api-documentation
We also prepared a sample API client here: https://github.com/SealSubscriptions/Seal-Subscriptions-php-API-client