Acknowledgement
A responder's signal that they have seen an alert and are handling it, which stops further escalation.Alert fatigue
When responders receive so many alerts, many not actionable, that they start ignoring or muting them and miss the ones that matter.Alert grouping
Combining many related signals, such as the same error repeated, into one problem so a responder sees it once.Alert noise
Alerts that don't need anyone to act: duplicates, known background errors, bots probing dead URLs, flapping checks.Blameless culture
Reviewing incidents by asking how the system allowed the failure rather than who caused it, so people report problems honestly.Check-in (cron monitoring)
A ping a scheduled job sends when it runs, so a monitor can alert when a run is late, missed or failed.Crash loop
A process that starts, crashes and is restarted repeatedly, usually after a bad deploy or a missing configuration value.Deploy marker
A record of when a new version went live, used to connect errors to the change that caused them.Error budget
The amount of unreliability an SLO allows over a period: with a 99.9% target, 0.1% of requests may failEscalation policy
The rules for who is alerted, in what order, and how long to wait before moving to the next person when nobody acknowledges.Failed deployment recovery time
DORA's measure of how long it takes to recover from a deployment that fails and needs immediate intervention.Fingerprint
A stable key computed from an error's type, stack and route, used to decide which events belong to the same problem.Flapping
A check or alarm that switches between failing and healthy repeatedly in a short time, producing a stream of open and close alerts.Floor signal
A Pagerless term: a signal that always wakes someone and can never be played down by the AIHeartbeat monitoring
Detecting a dead service by expecting a regular signal from it and alerting when the signal stops.Incident
An unplanned interruption or degradation of a service that needs a response.MCP (Model Context Protocol)
An open protocol that lets AI assistants and coding agents call tools on external services in a standard way.MTTA
Mean time to acknowledge: the average time from an alert being sent to a responder acknowledging it.MTTR
Mean time to recovery (or restore, or resolve): the average time from an incident starting to service being restoredObservability
How well you can understand a system's internal state from what it emits: logs, metrics and traces.On call
Being the person responsible for responding when a production system breaks during a set period, including outside working hours.OpenTelemetry
A vendor-neutral standard and set of SDKs for producing logs, metrics and traces, sent over the OTLP protocol.Paging
Interrupting a person to demand attention now, usually by push notification, phone call or SMS, named after the pagers on-call engineers once carried.Postmortem
A written review after an incident: what happened, the impact, the cause, and what will change so it doesn't recurRollback
Returning a service to its previous known-good version after a bad deploy.Runbook
Written steps for handling a known kind of problem, so whoever is on call can act without deep context.Severity
A label for how bad an incident is, often SEV1 to SEV4, used to decide who responds and how fast.SLA
Service level agreement: a contract with users that includes consequences for meeting or missing the SLOs it contains.SLI
Service level indicator: a carefully defined quantitative measure of some aspect of service, such as the share of requests served successfully.SLO
Service level objective: a target value or range for an SLI, such as 99.9% of requests succeeding over 30 days.Time-Sensitive notification
An iPhone notification level that breaks through Focus modes and notification summaries, but not the ring/silent switch.Uptime
The share of time a service is available
On-call terms, plainly
Glossary
Every term you meet in on-call and incident response, in one or two sentences, with how Pagerless uses it.
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