A Service Level Agreement (SLA) is a document that gives human readers the information necessary to decide how and whether to invoke a particular service from other software. The presence and use of an SLA varies by SOA vendor and corporate user. If present, the SLA
includes elementary-access and proposed-contract details in most cases
may be written by software designers to help negotiate what functionality is to be included in a given service
may communicate plans to potential service users and other interested parties
may be the basis of a legal document that indicates what level of reliability the service offers (for example, how many hours per week the service is available)
may be used as an input to an automated process that creates invocation details for use when developing a requester