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checker
Color Contrast Checker (WCAG)
Check foreground and background color contrast against WCAG 2.1 AA and AAA accessibility standards.
color contrast checkerwcag contrast
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9 tools
Free Checker Tools
Check and validate your work with diff checkers, regex testers, JSON validators, and code analysis tools.
📊
checker
Diff Checker
Compare two text blocks line by line and review added, removed, and unchanged lines in a clear diff view.
diff checkertext compare
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checker
Screen Resolution Tester
Detect your current screen size, browser window dimensions, DPR, color depth, orientation, and retina status.
screen resolutionwhat is my screen resolution
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IP Address Info
Check your public IP address, IPv4 or IPv6 availability, and location details such as city, ISP, and timezone.
what is my ipmy ip address
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Cron Expression Parser
Parse five-field cron schedules into human-readable text, explore presets, and preview the next execution times.
cron expression generatorcron parser
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checker
JWT Decoder
Decode JWT headers and payloads, inspect token claims, and review signature bytes without sending data anywhere.
jwt decoderjwt parser
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checker
HTTP Status Code Reference
Search common HTTP response codes, filter by category, and expand each status for details and practical use cases.
http status codeshttp status code list
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checker
AI Content Detector
Analyze pasted text for AI-like patterns using transparent heuristics such as sentence uniformity, vocabulary diversity, and a rough perplexity-style score.
ai detectorai content checker
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checker
Grammar Checker
Highlight common grammar, spelling, capitalization, and repeated-word issues with a basic rule-based browser checker.
grammar checkgrammar checker online
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