An API monitor calls one endpoint with the method, headers, JSON body and auth you configure, then scores the response against the status codes you accept and the response time you allow.
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API monitor · checked every 60s
Configuration
Failed checks 3 in the last hour
Why this is an issue and not downtime
The endpoint answered — it is reachable. It answered 502, which is outside the accepted status codes, so ErrorDetector records a failed check. Uptime stays honest; the alert still fires.
Each feature earns its place by making the client relationship easier to protect: fewer surprises, clearer proof, and faster explanations when something changes.
List the status codes this endpoint is allowed to return — 200, 201, 204, whatever it actually answers with — and a response-time limit in milliseconds (2000 ms unless you change it). A response outside either rule is a failed check.
Choose HEAD, GET, POST, PUT, PATCH or DELETE, add request headers as JSON for a bearer token or API key, send a JSON request body, and supply Basic auth credentials where the endpoint needs them.
Each check records how long the endpoint took, in milliseconds. Slow drift shows up on the monitor’s history long before the endpoint starts returning errors.
Prove SLA compliance with up to 24 months of uptime history on paid plans. Every month ErrorDetector e-mails you a client-ready uptime report you can forward as it is.
Every call records two separate things: whether the endpoint answered at all, and whether the answer passed your rule. Mixing those two is how an uptime figure ends up lying to a client.
Shown as “Passing”
The endpoint answered with a status code you accept, inside your response-time limit.
Shown as “Failed check (HTTP 503)”
The endpoint answered — there is a status code and a response time — but it fell outside your accepted codes, returned a 4xx or 5xx, or came back slower than your limit. The API is reachable, so this is not downtime. The alert names the reason, and your uptime percentage is untouched.
Shown as “Down”
Nothing answered: the connection timed out or was refused, the name did not resolve, or TLS failed. That is a reachability failure — it opens an incident and it is the only thing counted against uptime.
Both states alert through every channel on the monitor. Only Down opens an incident and moves the uptime number, so ninety seconds of 503s during a deploy is reported as what it was: a failed check on a server that never went away.
Concrete moments from the feature: setup, the signal that matters, and the client-facing proof that makes maintenance feel easy and valuable.
Monitor setup · example data
Method, headers, request body and the status codes you accept — everything the check needs.
Method
POST
Accepts
200, 201Endpoint
https://api.acmecorp.com/v1/orders
Request headers
Authorization: Bearer *** · Content-Type: application/json
Request body
{"sku": "AC-1042", "qty": 1}
Live result · example data
The endpoint answered, so uptime is untouched. The policy failed, so you still get told.
Response time
184 ms
Policy
FailedPOST /v1/orders
HTTP 503 is not in this monitor’s accepted status codes
Reachability
The host answered in 184 ms — the uptime bar stays green
Alert
Sent after 3 failed checks in a row, so a deploy blip stays quiet
Client proof · example data
One month of recorded reachability, with the failed policy checks listed separately.
30-day uptime
99.98%
Report
E-mailedUptime
Measured from recorded reachability only
Failed checks
Responses outside 200, 201 during the month
Slowest response
Recorded 03:12 UTC on the orders endpoint
Add the signal once, then let alerts, history, and reports build automatically.
Paste the API URL and pick the HTTP method the endpoint expects.
Add request headers as JSON, a JSON body if the endpoint needs one, and Basic auth credentials where they apply.
List the status codes you accept and the response time above which the check should fail.
ErrorDetector calls the endpoint on your plan interval, alerts your channels, and e-mails a client-ready uptime report every month.
Any HTTP endpoint — REST and GraphQL are the everyday cases. The request body is sent as JSON, so an endpoint that insists on an XML or form-encoded body cannot be given one; you can still monitor it with a GET or HEAD request and score it on the status code and response time.
Not on an API monitor. The pass rule there is the status code plus the response-time limit. If you need to assert on what came back, point a keyword monitor at the same URL — it searches the response text for a string you choose.
Within a check interval of the failure being confirmed. Solo and Team plans check every 60 seconds; the Enterprise plan checks every 30 seconds. By default a monitor has to fail three checks in a row before it says anything, so a single deploy blip stays quiet.
Yes. API, keyword, cron, DNS and SSL monitors live in the same dashboard and share the same alert channels. Paid plans unlock every monitor type; the Free plan covers HTTP monitors only.
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