UPC Barcode Validator - Online Check Digit & EAN
Enter a UPC or EAN barcode number and validate the check digit. See if it's a real product code. Local calculation.
UD5 Toolkit
Check if a URL is allowed or disallowed for any crawler. Paste or fetch any robots.txt to inspect rules instantly.
/.Fetch or paste a robots.txt, then test a URL path.
/robots.txt) that tells search engine crawlers and other bots which pages or sections of the site they are allowed or disallowed to crawl. It follows the Robots Exclusion Protocol (REP).* wildcard matches any character sequence, and $ forces an exact end-of-path match.<meta name="robots" content="noindex"> tag or an X-Robots-Tag: noindex HTTP header. For complete protection, combine both robots.txt disallow and noindex tags.* character serves two purposes in robots.txt: (1) As a user-agent value, User-agent: * means the rules apply to all bots that don't have a more specific block. (2) In path patterns, * matches any sequence of characters. For example, Disallow: /*.pdf$ blocks all PDF files regardless of directory. Combine with $ for precise matching.User-agent: * Disallow: /This tells every bot (
*) that the entire site (/) is disallowed. Note that well-behaved bots respect this, but malicious bots may ignore robots.txt entirely.Crawl-delay: 10 means 10 seconds between crawls. Googlebot does not support Crawl-delay — use Google Search Console to adjust crawl rate. Bingbot and YandexBot do respect it. Use it sparingly; setting it too high can slow down indexing./robots.txt to your domain: https://yourdomain.com/robots.txt. If you see a 404 error, your site doesn't have one — which means all bots are allowed to crawl everything. Use this tool to fetch and inspect any site's robots.txt instantly.* (wildcard for any character sequence) and $ (end-of-path anchor). It does not support full regular expressions, character classes, or alternation. For more granular control, use meta robots tags or HTTP headers on individual pages.Disallow: with no path (means nothing is blocked — use Disallow: / to block all); (3) Relying solely on robots.txt for hiding sensitive content (use authentication instead); (4) Wrong path format — paths are case-sensitive and prefix-matched; (5) Not testing — always use a tester like this one before deploying!User-agent: line starts a new block. You can target specific bots with tailored rules. Example: block Googlebot-Image from your /images/ folder while allowing all other bots. You can also group multiple user-agents together by listing them on consecutive lines before the rules — they'll share the same Allow/Disallow directives.Enter a UPC or EAN barcode number and validate the check digit. See if it's a real product code. Local calculation.
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Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
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Build a properly formatted robots.txt file with user-agent rules and sitemap location. Validate syntax in real time. Essential for webmasters.
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Online JSON formatting and validation tool, supporting JSON minify/beautify, syntax highlighting, and error locating. Data processed locally in browser for security.