Public DNS, HTTPS and deployment checks, plus offline email header and delivery-log tracing.
Free
3 servers across cloud & devops and analytics & monitoring. The largest is Oldweb Diagnostics.
Cloud & DevOps · Analytics & Monitoring
Public DNS, HTTPS and deployment checks, plus offline email header and delivery-log tracing.
Offline log parsing, CI failures, HTTP capture analysis and bounded JSON configuration validation.
Inspect IPv4/IPv6 subnets, allocate labeled prefixes and detect overlaps with exact address counts.
The rest either hold an API key issued by the publisher or ask for nothing.
Listed without a verification tick. Read the listing before installing.