Copyleaks API V3 is now available as a beta release.
The documentation can be found here

The Copyleaks API is a powerful yet simple tool to integrate within your platform and allows you to add content authentication capabilities in just a few minutes.

Here you can find all the needed documentation for a seamless integration including SDKs with code examples, methods documentation, technical specifications and more:

Official SDKs

Seamlessly integrate your application with the Copyleaks plagiarism detection services using our SDKs which are tailored to your programming language. Go-to SDK Download page.

REST API methods:

Other resources: