HttpMaster - HttpMaster is a professional software tool for testing and debugging HTTP applications, primarily aimed at REST API applications and web services.
Dr. Link Check - Broken link checker with malware and parked domain detection
Hoppscotch - Open source API development ecosystem
BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
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LinkChecker - LinkChecker is a free, GPL licensed website validator.