Artillery offers load and continuous performance testing for teams testing traffic spikes before release.
Scripts simulate traffic against APIs and sites.
When testing traffic spikes before release, watch error rates as request load rises.
Gatling offers a performance testing and traffic simulation platform for teams observing latency under service pressure.
Apache JMeter offers a protocol and service load testing tool for teams comparing API behavior at different concurrency levels.
Locust offers Python-based load testing for teams designing concurrent requests around real flows.