cdncheck is a Go library and CLI tool for identifying whether an IP address or domain belongs to a CDN, WAF, or cloud provider. It uses embedded CIDR range data (compiled from ASN, URL, and static CIDR sources) and efficient IP matching via the `bart` radix tree. The library provides a clean `Client` interface with methods like `CheckCDN`, `CheckCloud`, `CheckWAF`, and `CheckDomainWithFallback` that also resolve DNS and check CNAME suffixes. The CLI wraps this with input/output handling, filtering, and JSON output. The codebase is well-structured, with clear separation between core logic, data generation, and CLI runner. It is actively maintained by ProjectDiscovery and used in their security scanning ecosystem.
OpenDoor is an advanced CLI security reconnaissance platform for directory discovery, subdomain enumeration, WAF detection, and content fingerprinting. It employs a modular architecture with a plugin-based analysis pipeline (sniffers), network transport abstraction (direct, proxy, VPN), and extensive output formatting (JSON, CSV, SQLite, SARIF). Its core scanning engine, state machine, and plugin systems demonstrate sophisticated engineering, featuring auto-calibration, semantic soft-404 diffing, and a clean exception hierarchy.