What is restspan?
restspan is a monitoring service that tracks API latency from various global regions. It is primarily used by developers to understand the performance of their REST and gRPC API endpoints. The service provides detailed insights into where latency occurs within each API call. Developers use restspan to call their HTTP and gRPC endpoints from multiple locations and record six specific timing spans for every attempt, such as DNS lookup and time to first byte. The service offers alerting capabilities, sending notifications to tools like Slack or PagerDuty, and provides status pages. It also stores detailed signals like percentiles, availability, and TLS chain information.