The document must describe the provided by the partners' services and indicate the criteria of their quality.
SLA should contain clearly indicated services which the customer, the contractor, the aggregator platform, the marketplace, or the IT customer expect to receive. Moreover, this document precisely defines which parameters (metrics) need to be monitored. A large amount of monitored parameters is a risk that in working with SLA, you can get lost and not follow the performance of this agreement. This means that in the future, all monitoring systems can work ineffectively and that further service will worsen. However, there is also a risk while using few metrics. In addition, you can set unachievable for some parameters criteria.
Basically, SLA is a number of target metrics or their boundary meanings, which should determine the quality of services provided.
SLA metrics should be understandable and measurable, displaying the quality of service and depending only on the contractor. For example, the "service quality" indicator may be universal if it has several parameters. Among them are a share of abandoned carts, a percent of refusals, and customer satisfaction after making a purchase. All these indicators can be part of the service quality, but none is universal or depends only on the performer. It might be worthwhile to apply the average of several parameters in cases like this. Or set marginal indicators for each metric. For example, the failure rate is not higher than 50%; the share of abandoned carts is not higher than 40%. Also, in SLA can be specified other marginal indicators which can affect the work of service. For instance, a customer's request response should not last longer than 15 minutes per working day if the number of simultaneous calls doesn't exceed 20 per hour or 150 during the work hours of a typical day. Such marginal indicators will help metrics to be realistic and achievable.
Activity in interactions with customers is a more straightforward and more measurable criterion. For example, in SLA, you can specify that responding to the buyer's request should not exceed 30 minutes. However, for such metrics, you should indicate different values for different conditions. For instance, demanding a seller to respond within 30 minutes on holidays or weekends may be impractical.
When choosing metrics for tracking and including in SLA, it's necessary to ensure that the service provider controls them. For example, declaring the delivery for the "next day," the seller may not fulfill this requirement because it's not always his responsibility (he could fail because of the logistics company that promised to deliver goods within 24 hours). On the one hand, the seller didn't fulfill his obligations, letting the buyer down because he needed the goods just the next day. On the other hand, the seller cannot influence the speed of the delivery operator, except that using the service of their competitor the next time.
One more important SLA aspect is notifications about the time allotted to the contractor for making changes in their work and the sanctions if there are no changes. In SLA, the ending of cooperation with companies whose quality of service is inappropriate according to the platform demands can be mentioned. However, you shouldn't stop working with them after the first misconduct. But, in case of systematic non-compliance of rules, the contractor should be aware that he will be blocked, and all relations will be terminated.