Service Level Agreement or SLA is a contract between a service provider and its customer. The customer can be either internal or external, depending on the organization and service area. Through an SLA, a service provider indicates the conditions under which it can perform the necessary work. An SLA helps service providers describe the scope of work and thus exempts them from any unwanted liability. For example, a telecommunications company`s SLA can promise a network availability of 99.999 percent (for non-inclined ones mathematically, this equates to about five and a half minutes of downtime per year which, believe it or not, may still be too long for some companies) and allow the customer to reduce their payment by a certain percentage if it isn`t. in general, on a sliding scale based on the magnitude of the offence. The coverage of the service by the [service provider], as described in this Agreement, follows the schedule set out below: the service elements include the particularities of the services provided (and what is excluded in case of doubt), the conditions of availability of the service, standards such as slots for each level of service (for example, prime time and non-prime time can have different service levels), the responsibilities of each party, escalation process and cost/service trade-off. This Agreement shall remain valid until it is replaced by a revised Agreement, approved by mutual agreement of the Interested Parties. Assumptions about online services and/or components include: based on the model above, this checklist is suitable for IT services – an application case, if not the most common, when it comes to service level agreements.