ESnet has designed a REST/JSON based lookup service called the "simple Lookup Service", or sLS. Clients can use simple HTTP POST to register list of key-value pairs called "records" and use HTTP GET to search and retrieve existing records from server. The lookup service may be run as a simple stand-alone server or as a distributed service. This service is initially targeted at perfSONAR, but also can be used as a general purpose search mechanism for any key-value pairs.