A Service Level Contract (SLA) is an agreement between a provider and an end user that clearly indicates and defines the level of service that the end user expects from the service provider. A Service Level Contract (SLA) is the service contract component between a service provider and a customer. ALS offers specific and measurable aspects related to the services offered. For example, ALS is often included in agreements signed between internet service providers (Internet service providers, ISPs) and customers. Since the late 1980s, SLAs have been used by fixed-line operators. Today, ALS is so widespread that large organizations have many different ALSs within the company itself. Two different units in an organization script an ALS, one unit being the customer and another the service provider. This helps maintain the same quality of service between different units of the organization and in several sites within the organization. This internal ALS script also compares the quality of service between an internal service and an external service provider.  Service providers need ALSs to help them manage customer expectations and define the degrees of severity and circumstances in which they are not held responsible for failures or performance issues. Customers can also benefit from SLAs, as the contract outlines the characteristics of the service — which can be compared to THE SLAs of other providers — and identifies ways to assess service issues. A web service level agreement (WSLA) is a standard for monitoring compliance with web services according to the service level agreement.
It allows authors to indicate performance metrics assigned to a web application, desired performance goals, and actions to perform if performance is not achieved. Another concrete example of ALS is an agreement on the service level agreement of an Internet service provider. This ALS contains a guarantee of operating time, but it also defines the expectations and latency of packages. Parcel delivery refers to the percentage of data packets received relative to the total number of data packets sent. Latency is the time it takes for a package to travel between customers and servers. Stakeholders — Clearly defines and defines the responsibilities of the parties to the agreement.