WebService::Pair EchoSignAPI(SOAP, REST);

Lets begin by getting introduced to the Web App and it's APIs that we will explore through this blog as a reference

The WebApp is EchoSign (www.echosign.com). EchoSign is an eSignature solution from Adobe that allows senders to get their documents (technically, agreements) signed by one or more recipients. EchoSign supports multiple signature workflows like sequential signing and parallel signing. It also enables scenarios like MegaSign for sending different copies of a document to thousands of different recipients in one go and also multiple recipients signing the same document hosted on our customers website. It allows various security options for preventing the signing and viewing agreement

EchoSign has several integrations with other third party solutions who from within the context of their service want to use EchoSign for sending documents for signature or to enable their own customers to managing their agreements. Examples of such integrations are with Salesforce and Box. All these integrations work by calling into EchoSign APIs and there is where our Pair comes into picture.

Historically, our integrations have used SOAP APIs which is now in Version 19 (yes!) and is documented here:-
https://secure.echosign.com/public/docs/EchoSignDocumentService19

More recently, many of our customers had been requesting for REST APIs and we shipped our Version 1 in December last year which is documented here :-
https://secure.echosign.com/public/docs/restapi/v2

And that's mostly it. I personally understand and learn things better when explained in the context of an example.  Though I had like you to go and use EchoSign as much possible, my focus here would be to talk about API Design using the pair I understand the best and learnt from the most

WebService::Pair<API, API> EchoSignAPI(SOAP, REST);