Synthetic monitoring
Synthetic monitoring checks a service by sending it requests on a schedule from outside, as a user would, rather than waiting for real traffic.
Checks range from a single request (is the page answering with 200 and the right text?) to scripted browser journeys that log in and click through checkout. Single requests are cheap and run every minute; browser journeys catch more but cost more and break when the page changes.
Because the traffic is generated, synthetic checks find outages at 3 a.m. when no user would report them, and they give a steady baseline for response times. Real-user monitoring complements them by showing what actual visitors experienced.
In OpenUptime
OpenUptime runs HTTP, TCP, DNS, WebSocket, PostgreSQL, MySQL and Redis checks, with keyword matching, from one or several regions. It does not run browser journeys.
Read about multi-region checks →
Questions
What is the difference between synthetic monitoring and RUM?
Synthetic monitoring sends its own requests on a schedule, so it works with no traffic. RUM measures real visitors in their browsers, so it shows true experience but only where there are users.
Is uptime monitoring a kind of synthetic monitoring?
Yes, the simplest kind: a scheduled request with a pass or fail result.
Related terms
Monitor it with OpenUptime
Checks from one or several regions, alerts to the tools you use, and a status page for your customers. Free to start, open source under the MIT license.
主动监控（Synthetic monitoring）
主动监控（synthetic monitoring）是按计划从外部向服务发送请求来检查它，就像用户在访问一样，而不是等真实流量来发现问题。
检查可以简单到单个请求（页面是否返回 200 且内容正确？），也可以复杂到用脚本驱动浏览器完成登录、结账等完整流程。单个请求成本低，可以每分钟运行；浏览器流程能发现更多问题，但成本更高，页面一改就容易失效。
由于流量是主动产生的，主动监控能在凌晨 3 点没人反馈时发现故障，也能为响应时间提供稳定的基线。真实用户监控（RUM）则是补充，展示真实访客的体验。
在 OpenUptime 中
OpenUptime 支持 HTTP、TCP、DNS、WebSocket、PostgreSQL、MySQL 和 Redis 检查，支持关键词匹配，可以从一个或多个区域检查。不支持浏览器流程检查。
常见问题
主动监控和真实用户监控（RUM）有什么区别？
主动监控按计划自己发请求，没有流量时也能工作。RUM 在真实访客的浏览器里测量，反映的是真实体验，但只有在有用户访问的地方才有数据。
可用性监控算主动监控吗？
算，而且是最简单的一种：按计划发请求，结果只有通过或失败。