UD5 Toolkit
Base64 String Validator - Online Check Valid Encoding
Paste a string and verify if it is valid Base64. Auto‑detects padding issues and character errors. Quick dev check.
Crypto Address Format Checker - Online Validate Wallet
Crypto Address Format Checker
Instantly validate wallet address formats for 10+ cryptocurrencies
Try a sampleBitcoin
1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLyFrequently Asked Questions
It validates the format of cryptocurrency addresses including length, character set, and basic checksum patterns. For Bitcoin, it distinguishes between Legacy (P2PKH), SegWit (P2SH), and Bech32 formats. For Ethereum/BNB, it checks the 0x prefix and hex structure. It does not check if the address is active or contains funds.
BTC, ETH, BNB (BSC), LTC, BCH, DOGE, XRP, TRX, SOL. More chains are added regularly. Each coin is validated against its unique address rules (Base58, Bech32, Hex, etc.).
You may have selected the wrong coin. Also, some newer address types (like Taproot for Bitcoin) might not be recognized yet. Ensure there are no extra spaces and the address is exactly as copied from your wallet.
A checksum is a short code derived from the address data that helps detect typing errors. For example, Bitcoin uses a double SHA-256 checksum at the end of its Base58-encoded address. If you mistype one character, the checksum will likely mismatch, making the address invalid.
No, this checker only validates raw hexadecimal Ethereum addresses (0x...). It does not resolve ENS domain names.
Absolutely! All validation happens in your browser. No data is sent anywhere. You can even save the page and use it without internet.
DNSSEC Chain Validator - Online Check RRSIG & DS
Validate a DNSSEC chain by entering DS and RRSIG records. Verify that signatures match. Educational. Local algorithm.
Duct Tape Sheet Calculator – Online Length for Wallet or Purse
Enter wallet size and get the exact length of duct tape strips needed to build a sheet. DIY crafting.
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.
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.
Random Crypto Key Generator - Online Create API Tokens & Secrets
Generate strong random strings for API tokens, session secrets, or encryption keys. Uses crypto.getRandomValues().
Twitter Card Previewer - Online See How Tweets Render
Enter a URL and fetch its Twitter card meta tags. See a live preview of how the tweet will appear. Debug social sharing.
JavaScript Syntax Validator - Online Check Errors
Paste JavaScript and catch syntax errors instantly with line numbers. Lightweight pre‑commit check. Local.
HTML Validator Lite - Online Check Syntax Errors
Paste HTML and detect unclosed tags, invalid nesting, and duplicate IDs. Lightweight client‑side validation.
HTML lang Validator - Online Check Language Tag
Validate a language tag like en‑US or zh‑Hans against the IANA registry. Ensure correct HTML lang attribute.
ETag & Last‑Modified Validator - Online Check Cache Headers
Send conditional requests to a URL and verify that the server correctly handles ETag and If‑None‑Match. Audit caching.
Geolocation to Address - Online Reverse Geocode
Enter latitude and longitude and get a human‑readable address using the browser's built‑in reverse geocoding (if available).
Robots.txt Tester - Online Check URL Allow/Disallow
Enter a URL and a user‑agent to see if it is allowed or blocked by the robots.txt file. Quick bot validation.
CSS Media Query Syntax Checker - Online Validator
Paste a media query and instantly check for syntax errors. See if it's correctly formed. Quick developer tool.
DNS Record Syntax Checker - Online Validate BEFORE Publishing
Paste any DNS record and check if its format is valid for the selected record type (A, AAAA, CNAME, MX, TXT, SRV). Prevents typos.
BIP39 Mnemonic Generator - Online 12/24 Words
Generate cryptographically secure BIP39 mnemonic phrases (12 or 24 words) for HD wallet seeds. All entropy generated locally.
SQL Syntax Validator - Online Quick Check
Paste your SQL query and check for basic syntax errors. Highlights missing commas, wrong keywords. Local analysis.
TOML Formatter & Validator - Online Config Tool
Check and beautify your TOML config files. Highlights errors and aligns tables and arrays. Safe local parsing.
YAML Validator & Formatter - Online Check Syntax
Validate YAML syntax with line‑by‑line error messages. Also format messy YAML into clean, indented output. All in your browser.
ISBN Validator - Online Check ISBN‑10 & ISBN‑13
Validate ISBN‑10 and ISBN‑13 numbers and compute their check digits. Useful for booksellers and libraries. All local.
IBAN Structure Checker - Online Validate Format & Country
Check if an IBAN has the correct length and structure for its country. Early validation, no bank connection.
Test Credit Card Validator - Online Luhn Check & Issuer
Paste a test card number to verify Luhn algorithm, identify issuer (Visa, MC), and check length. No real data.
Semantic Versioning Validator - Check Semver Syntax
Validate if a version string follows SemVer 2.0.0. Also sort and compare versions. Developer tool.
Markdown Linter - Online Check Syntax & Style
Paste Markdown and get warnings for common mistakes: inconsistent heading spacing, bare URLs, and broken links. All local.
Robots.txt Validator - Online Check Syntax & Rules
Paste a robots.txt file and validate its syntax. See if a specific user‑agent can access a path. Essential for webmasters.
Envelope Addressing Tool - Online Print Address on Envelope
Type sender and recipient addresses and format them for printing on a standard envelope. No special software.
PRNG Validator - Online Check Randomness Pattern
Paste a list of numbers to visually check uniformity, mean, and simple pattern analysis. Educational tool for statistics and RNG.
Crypto Price Ticker - Online Live Bitcoin & Ethereum
Live cryptocurrency prices from public APIs. Clean ticker with percentage changes. Pure frontend, no account needed.
XML Formatter & Validator - Free Online XML Beautifier
Easily format, validate, and beautify XML documents. Minify XML data with a single click. All processing happens locally in your browser for maximum privacy.
JSON Formatter & Validator - Online JSON Beautifier
Online JSON formatting and validation tool, supporting JSON minify/beautify, syntax highlighting, and error locating. Data processed locally in browser for security.