These platforms are subscription only and will require a username and password.
Both Lexis and Westlaw provide a myriad of international materials such as treaties and other international agreements, periodicals on international topics, legal treatises on a variety of topics concerning international law and even some primary materials of select countries. Both platforms provide access to International Legal Materials; a publication that reprints a variety of materials that might include foreign cases, private agreements, trade pacts, and more. Often the materials are printed in English and may be the only English translation of a document.
The newest interface of the Westlaw databases works on natural language searching in a "one box" search. All International materials have been included in this new interface.
LexisAdvance also uses a "one box" search with natural language. There are treaty materials available as well EU materials and the domestic laws of many countries. Many scholarly treatises and practice guides are included in the academic subscription that may have chapters with an international focus or discuss the law of a certain country.