JSON-LD Validator - Online Structured Data Syntax Checker
Paste JSON-LD and validate basic syntax and required properties for Article, Product, etc. Local only. Instant feedback.
UD5 Toolkit
Validate your Web App Manifest for installability, completeness, and best practices
<link rel="manifest" href="/manifest.json"> and is essential for making your web app installable.
<link> tag in the <head> section of every HTML page: <link rel="manifest" href="/manifest.json">application/manifest+json. For full PWA support, you'll also need a service worker registered on your pages.
"/" or "/app/"). If not specified, the browser defaults to the directory containing the manifest.
display not set to standalone/fullscreen/minimal-ui, or the user has previously dismissed the prompt. Use this validator to check your manifest and also verify your service worker registration and HTTPS setup.
short_name is not provided, the browser truncates name for the home screen label, which may result in an awkward display. Providing both gives you full control over how your app name appears in different contexts.
Paste JSON-LD and validate basic syntax and required properties for Article, Product, etc. Local only. Instant feedback.
Enter a UPC or EAN barcode number and validate the check digit. See if it's a real product code. Local calculation.
Learn how to register your PWA to handle custom URL protocols. See the manifest entry and test.
Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.
Register a periodic background sync and see the status. Schedule content updates for your PWA. API demo.
Check if the browser has captured the beforeinstallprompt event. Understand why your PWA is (or isn't) installable.
Enter a URL and fetch its Twitter card meta tags. See a live preview of how the tweet will appear. Debug social sharing.
Paste HTML and detect unclosed tags, invalid nesting, and duplicate IDs. Lightweight client‑side validation.
Send conditional requests to a URL and verify that the server correctly handles ETag and If‑None‑Match. Audit caching.
Enter latitude and longitude and get a human‑readable address using the browser's built‑in reverse geocoding (if available).
Paste a media query and instantly check for syntax errors. See if it's correctly formed. Quick developer tool.
Check if your page triggers the beforeinstallprompt event. Simulate the install flow. Debug PWA installability.
Upload a 512x512 logo and get resized icons for every PWA requirement. Download a zip and the corresponding manifest.json snippet.
Validate a DNSSEC chain by entering DS and RRSIG records. Verify that signatures match. Educational. Local algorithm.
Register a periodic background sync to fetch fresh data even when the tab is closed. Understand the API and limits.
See the current state of a Service Worker for your page: installing, waiting, active. Unregister or skip waiting. Developer utility.
Paste any DNS record and check if its format is valid for the selected record type (A, AAAA, CNAME, MX, TXT, SRV). Prevents typos.
Paste your SQL query and check for basic syntax errors. Highlights missing commas, wrong keywords. Local analysis.
Paste a Bitcoin, Ethereum, or other crypto wallet address and quickly verify its format and checksum. No connection to blockchain.
Validate YAML syntax with line‑by‑line error messages. Also format messy YAML into clean, indented output. All in your browser.
Validate ISBN‑10 and ISBN‑13 numbers and compute their check digits. Useful for booksellers and libraries. All local.
Check if an IBAN has the correct length and structure for its country. Early validation, no bank connection.
Paste a test card number to verify Luhn algorithm, identify issuer (Visa, MC), and check length. No real data.
Validate if a version string follows SemVer 2.0.0. Also sort and compare versions. Developer tool.
Paste Markdown and get warnings for common mistakes: inconsistent heading spacing, bare URLs, and broken links. All local.
Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
Paste a string and verify if it is valid Base64. Auto‑detects padding issues and character errors. Quick dev check.
Paste a list of numbers to visually check uniformity, mean, and simple pattern analysis. Educational tool for statistics and RNG.
Easily format, validate, and beautify XML documents. Minify XML data with a single click. All processing happens locally in your browser for maximum privacy.
Online JSON formatting and validation tool, supporting JSON minify/beautify, syntax highlighting, and error locating. Data processed locally in browser for security.