E-Signing Platform with Robust API Development

I'm looking to create an e-signing platform with a robust API. This isn't just any signing service, it should have the capability of dynamically generating PDF documents from templates and more importantly, it must have seamless e-signing capabilities.

Key Features:
- Generating PDF documents based on certain templates.
- E-signing capabilities, allowing users to e-sign the generated documents.
- Adherence to legal frameworks for e-signatures ensuring all documents are legally binding.
- An API that allows integration with other applications.

Though the functionality is the main focus, interface design is not to be overlooked. The user-experience should be smooth and intuitive.

Below is what I am expecting from interested freelancers:

Skills and Experience:
- Experienced in web and API development.
- Knowledge in legal frameworks for e-signing processes.
- Proven record in developing e-signing platforms or similar projects.
- Great UI/UX design skills.
- Experience with PDF generation.
- Robust portfolio showcasing relevant skills.

If you have the right skills and experience to make this happen, kindly place your bid.