The Platform API has two versions, and documentation is being moved here. In the meantime, you can find the documentation on our old documentation sites:
V2: https://apidocs-docue.vercel.app
In all new integrations you should start using the V2 api.V1 (legacy): https://apidocs.docue.com
If you have any questions about the Platform API, please feel free to contact support@docue.com.