Updated 25 October 2026 · By the Upcertain team
Request
| Option | Values | Default |
|---|---|---|
| URL | http:// or https://, up to 2,048 characters | required |
| Method | GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS | GET |
| Headers | Up to 30, values up to 4,096 characters | none |
| Body | Up to 64 KB, sent with methods other than GET and HEAD | none |
| Basic authentication | Username and password | none |
| Timeout | 1 to 60 seconds | 30 seconds |
| Follow redirects | On or off | on |
Expected status codes
By default any status from 200 to 399 is up. Write your own rule as a comma-separated list of codes, classes and ranges:
200exactly 200.2xxany 2xx status.200-299, 301a range plus one code.401useful for endpoints that must refuse anonymous requests, such as an API behind authentication.
Certificates
HTTPS monitors check the certificate on every request: an expired certificate, a hostname mismatch or a broken chain fails the check. Warnings are sent before expiry, by default 30, 14 and 7 days ahead; you can choose up to five days between 1 and 90. See SSL monitors.
Interval and confirmation
Choose the interval (30 s to 24 h, limited by your plan) and, under Advanced settings, how many confirmation checks run before an incident opens and how far apart. See confirmation checks.
What a failure records
The incident names the cause: the status code, a timeout, a DNS failure, a refused connection, too many redirects or the certificate problem. The response time recorded with each check is the time to the response headers.
Requests from Upcertain
Checks come from Seoul with the user agent Upcertain-Monitor/1.0 (+https://upcertain.com). Upcertain refuses to check private, loopback and link-local addresses, including where a redirect leads.