Clio-API enables development of integrations that interact with the cloud-based legal practice management platform Clio, which is used by over 150,000 legal professionals around the world. Implementation questions and challenges are discussed using the clio-api tag in Stack Overflow.
Questions specific to the OAuth or REST APIs documented here: https://app.clio.com/api/v4/documentation
Clio is in the process of shifting over to the new Clio API V4 and preparing to deprecate Clio API V2 in October 2018.