Monitor protocols
Active monitoring sends a probe from Crystade on a fixed interval. This page lists protocol options, results, and error codes. How to create a monitor is in Create an availability monitor.
UDP is not available. TLS certificate checks and Check Script require Starter or Standard.
Shared limits
Section titled “Shared limits”| Limit | Value |
|---|---|
| Connection timeout | Max 5 minutes |
| Upstream response | 32 MB |
| HTTP request body | 64 KB |
| HTTP request headers | 20 entries |
| HTTP redirects | Max 10 |
| HTTP versions | HTTP/1.0, HTTP/1.1, HTTP/2.0 |
| Allowed intervals | 15s, 30s, 1m, 3m, 5m, 15m, 30m, 6h, 12h, 24h |
| Cloud regions | europe-north1, us-west1, asia-southeast1, australia-southeast1 |
Timing metrics
Section titled “Timing metrics”| Metric | Meaning |
|---|---|
| TTDR (time to DNS resolved) | From check start to hostname resolution |
| TTFB (time to first byte) | From check start to the first byte after the request starts |
| RTT (round trip time) | From check start to connection finished, interrupted, or max response body reached |
Options: URL, request headers, request body (plain text, JSON, or XML), redirect-follow limit, connection timeout.
Result: protocol, TTDR, TTFB, RTT, response headers, response body, error code, error message.
HTTP inherits TCP error codes and adds HTTP-level failures such as non-success status depending on your assertions.
Options: host, port, connection timeout.
Result: TTDR, TTFB, RTT, error code, error message.
Error codes: resolve_host_failed, invalid_address, unknown_protocol, invalid_config, connection_refused, connection_timeout, connection_reset, network_unreachable, connection_failed.
Options: host, port, connection timeout.
Result: verified certificate chain, overall status, TTDR, TTFB, RTT, error code, error message.
TLS 1.2 and TLS 1.3 are supported.
Error codes: all TCP codes, plus tls_handshake_failed.
Certificate fields: Subject, Issuer, Serial, Not Before, Not After, Version, DNS Names, IP Addresses, Is CA, Signature Algo, Public Key Algo, SHA256 Fingerprint, Status.
Certificate status (Chromium-aligned): OK, CERT_COMMON_NAME_INVALID, CERT_AUTHORITY_INVALID (self-signed), CERT_SELF_SIGNED_LOCAL_NETWORK, CERT_VALIDITY_TOO_LONG, CERT_DATE_INVALID (not-yet-valid), CERT_DATE_INVALID (expired), CERT_WEAK_SIGNATURE_ALGORITHM, CERT_WEAK_KEY, CERT_NO_REVOCATION_MECHANISM.
Minecraft
Section titled “Minecraft”Options: host, port, connection timeout, protocol version.
Result: version, MOTD, players, max players, TTDR, TTFB, RTT, error code, error message.
Error codes: all TCP codes, plus handshake_timeout, handshake_failed, malformed_response.
Check logs
Section titled “Check logs”Each check log stores the monitor snapshot, location, per-protocol request snapshot, per-protocol response snapshot, and timing breakdown. Logs are immutable. Visibility into history is plan-gated (30 / 90 / 365 days); retention itself is not.