I am trying to find an api, that enables me to sign documents using Xamarin app. All the apis that I see online asks me to upload the document on their servers. For example, docusign allows me to upload document to a server, and then provide REST services, or Webhooks to access them in the app.
Problem is I can't upload documents anywhere or rather can never get approval to upload them online. So, other than creating my own implementation of e-signature, I will have to find an api, which can work without any document upload.
Is there an api that can do it? Basically if I send the image of signature and document id to it, it can create a e-signature based on that? Or maybe an api that allows access the way we access gallery or contacts in Android or how third party payment system works?