What is uptime monitoring?
Uptime monitoring is the practice of automatically checking a website or API from outside its own infrastructure at a fixed interval, so its operator learns about an outage from an alert rather than from users.
What is a status page?
A status page is a public web page where a service publishes its current operational state, active incidents, and planned maintenance, giving customers a self-serve answer to "is it down for everyone or just me?".
What is a heartbeat (dead-man’s switch)?
A heartbeat check expects a periodic ping FROM your system; the alert fires when the ping stops arriving. It monitors things that cannot be probed from the outside, like cron jobs and background workers.
What is SSL certificate expiry monitoring?
SSL expiry monitoring tracks how many days remain on a site’s TLS certificate and alerts before it lapses, preventing the browser security errors an expired certificate causes.
What is DNS monitoring?
DNS monitoring verifies that a hostname resolves correctly and that its records have not drifted — catching expired domains, broken delegations, and hijacked or misconfigured records.
What is synthetic monitoring?
Synthetic monitoring runs scripted checks against a service from outside its own infrastructure on a fixed schedule, simulating a request instead of waiting on real user traffic. HTTP, API, and browser checks are all forms of synthetic monitoring.
What is API monitoring?
API monitoring sends requests to an API endpoint and validates the response — its status code, its structure (for example with JSONPath or JSON Schema assertions), and its response time — rather than just loading a web page. Multi-step checks chain several requests to exercise a whole workflow.
What is uptime percentage?
Uptime percentage is the share of a period during which a monitored service was available; for example, 99.9% over 30 days corresponds to roughly 43 minutes of allowed downtime. It is the headline reliability number that SLAs and status pages usually report.
What is a service level agreement (SLA)?
A service level agreement (SLA) is a formal, often contractual commitment to a level of service — such as 99.9% monthly uptime — together with the remedy owed if the target is missed. Monitoring supplies the measurements used to verify it.
What is a service level objective (SLO)?
A service level objective (SLO) is an internal reliability target a team sets for itself, such as 99.9% of checks succeeding over 30 days. It is usually stricter than any externally promised SLA so problems surface before customers are affected.
What is an error budget?
An error budget is the amount of unreliability an SLO permits over a period — the difference between 100% and the target. Once it is used up, teams typically slow down risky changes until reliability recovers.
What is an incident?
An incident is a tracked record of an outage or degradation, opened automatically when checks cross the failure threshold and closed when they recover. Its lifecycle — open, acknowledge, resolve, reopen — and its updates can be published to a status page.
What is an alert threshold?
An alert threshold is the number of consecutive failed checks required before a monitor is treated as down and an incident opens, which filters out isolated blips. A matching success threshold controls when the incident resolves; the failure threshold defaults to 2 and the success threshold to 1, so an incident opens after two bad checks and clears on the first good one.