Which SLIs/SLOs are relevant for API gateways?

When monitoring API gateways, key Service Level Indicators (SLIs) and Service Level Objectives (SLOs) help ensure optimal performance and reliability. Here are some relevant SLIs/SLOs for API gateways:

• Response Time: Measures how long it takes for the API to respond to requests. An example SLO could be 95% of requests must be responded to in under 200 milliseconds.
• Availability: This SLI tracks the uptime of the API gateway. An example SLO could specify 99.9% uptime over a monthly period.
• Error Rate: This measures the percentage of API calls that result in errors. A common SLO might be that the error rate should be less than 1% over a defined period.
• Throughput: Refers to the number of requests served per second. An example SLO might state that the API gateway should handle at least 1000 requests per second under peak load.
• Latency: Measures any delays in the processing of requests. An SLO could indicate that 95% of requests should have a latency of less than 150 milliseconds.