Pay for checks, not for monitors按检查次数付费，不按监控数量

Each check that makes a request costs one credit, whether it succeeds or fails. Heartbeat monitors only receive pings from your service, so they cost nothing.每执行一次监控检查消耗 1 个额度，不论成功或失败。Heartbeat 监控只接收你的服务发来的请求，不消耗额度。

Checks pause until the next period or until you upgrade. Existing monitors, history and status pages are kept.监控暂停执行检查，直到下个周期重置或你升级套餐。已有的监控、历史数据和状态页不会被删除。

Alert emails and status-page subscriber notifications share the monthly email allowance. Past it, only email pauses; Slack, webhooks and other channels keep sending. Sign-in, verification and password-reset mail is never counted.告警邮件与状态页订阅者通知共用每月邮件额度。超出后只暂停邮件，Slack、Webhook 等其他渠道照常发送。账号验证和密码重置邮件不受限制。

Yes, on Lite and above. For every https monitor we read the site's certificate about every six hours and alert you 14 days before it expires (7, 3 and 1 day too), when it expires or stops being trusted, and when it is renewed. Alerts go to the monitor's channels and do not open an incident or count toward a status page. The warning window is adjustable from 1 to 90 days. Only port 443 is checked, and this automatic reading does not cost check credits. A standalone SSL monitor (pick type SSL and enter a hostname) is different: it checks only the certificate, as often as you choose (at most hourly, 6 hours by default), opens an incident and uses one credit per check.会，Lite 及以上套餐可用。对每个 https 监控，我们大约每六小时读取一次站点证书：到期前 14 天提醒（之后 7、3、1 天再提醒），证书过期或不受信任时告警，续期后通知。提醒发往该监控的告警渠道，不会创建事件，也不影响状态页。提前提醒的天数可在 1 到 90 天之间调整。只检查 443 端口，这种自动读取不消耗检查额度。单独的 SSL 监控（类型选 SSL，填写域名）则不同：它只检查证书，频率自选（最短每小时，默认 6 小时），出问题时创建事件，每次检查消耗 1 个额度。

On Team, monitors can run every 30 seconds (every other plan: 1 minute at the shortest). Each check still costs one credit, so a 30-second monitor uses 86,400 checks a month, twice a 1-minute one. Sub-minute checks are scheduled in 3-second steps, so successive checks may land a few seconds off 30.Team 套餐的监控可以每 30 秒检查一次（其他套餐最短 1 分钟）。每次检查仍消耗 1 个额度，所以一个 30 秒的监控每月消耗 86,400 次，是 1 分钟监控的两倍。亚分钟检查以 3 秒为粒度排程，相邻两次检查的间隔可能与 30 秒相差几秒。

Each plan sets the longest your check results and alert log are kept: check history from 30 days on Free to 365 on Team, the alert log from 14 to 365 days. A new workspace starts on the Free values; set how long to keep each one in Settings, up to your plan's limit. Hourly uptime summaries are kept for a year on every plan, so uptime percentages do not shrink.每个套餐规定检查结果和告警日志最长保留多久：检查历史从 Free 的 30 天到 Team 的 365 天，告警日志从 14 天到 365 天。新建工作区按 Free 的值起步，之后可在「设置」中调整，上限为套餐允许的天数。每小时的可用率汇总在所有套餐都保留一年，可用率百分比不会因此缩短。

Yes, from the billing portal in Plan & usage. Changes are prorated by Stripe. When a plan ends or you move to a smaller one, what no longer fits is adjusted once: intervals shorter than the new plan allows are lengthened to its shortest, monitors beyond its cap are paused (the oldest stay active; nothing is deleted), history settings shorten to its limit, and custom status-page domains are released, so connect them again after upgrading to Team. Moving up never lengthens or speeds anything by itself: you resume monitors, pick a shorter interval and set retention yourself.可以，在「套餐与用量」页进入账单门户操作，费用由 Stripe 按比例结算。套餐到期或降级时，超出新套餐的部分会一次性调整：短于新套餐下限的检查间隔会延长到下限，超过监控上限的会被暂停（保留最早创建的，不删除任何监控），历史保留天数缩短到新套餐的上限，状态页的自定义域名会被解除绑定，重新升级到 Team 后需要再绑定一次。升级不会自动恢复或加快任何东西：由你自己恢复监控、选择更短的间隔、设置保留天数。