Validator Tools

Validate data formats and schemas—JSON, HTML, CSS and more—with clear error messages and instant feedback for reliable data validation and quality assurance.

19 tools available

Blockchain Tools 4

Checksum Address Converter

Validate, fix and batch-convert Ethereum addresses to EIP-55 checksum format. Keccak-256 mixed-case validation for ETH, BSC, Polygon. 100% client-side.

BIP39 Mnemonic

Generate or validate BIP39 seed phrases (12-24 words), apply an optional passphrase (25th word), and derive the PBKDF2-HMAC-SHA512 512-bit seed hex.

Crypto Address Validator

Validate Bitcoin, Ethereum, Solana, Tron, Litecoin and 12 chains with real EIP-55, Base58Check and Bech32m checksum verification. Batch mode, CSV/JSON, in-browser.

Wallet Address Validator

Validate any wallet address offline: Bitcoin Base58Check + Bech32, Ethereum EIP-55, Solana, Tron, Cardano, Stellar. Batch CSV/JSON export, no API, in-browser.

Developer Tools 8

Generators 3

Regex Generator

Visual regex builder + live tester: highlight matches, capture groups, lookahead, replace preview, export valid JS/Python/PHP/Java/Ruby/Go code. No install.

Robots.txt Generator

Build a robots.txt with a live URL tester and an RFC 9309 (Robots Exclusion Protocol) compliance linter. WordPress, e-commerce & blog presets included.

Sitemap Generator

Build sitemap.xml with lastmod, changefreq and priority. Auto-splits past the 50,000-URL limit into a sitemap index, validates, ready for Search Console.

Utilities 5

Robots.txt Tester

Test robots.txt rules with RFC 9309 group selection and Allow/Disallow precedence. Bulk-check URLs per bot, export CSV. Blocking is not deindexing.

CSS Specificity

Compute CSS specificity for any selector with a color-coded breakdown, multi-selector comparison, and a source-order tiebreaker for specificity ties.

HTTP Status Codes

Complete HTTP status code reference. Search 60+ codes (100–511) with definitions, RFC links, cacheable & retryable flags. Covers 200, 301, 404, 429, 500.

OpenAPI Spec Validator

Validate an OpenAPI 3.x JSON or YAML spec online: lint structure, summarize endpoints, detect broken $ref, catch missing 401/403 and undeclared params. Free.

Password Strength Tester

Check password strength with real-time entropy and brute-force crack-time analysis. Pick a GPU attacker model, test NIST 800-63B, generate secure passwords.

File Tools 2

Hash Checker

Calculate AND verify MD5, SHA-1, SHA-256, SHA-512 file hashes in your browser. Paste the publisher's expected hash and get an instant Match / Mismatch result.

Type Detector

Detect a file's real type by its magic number, not its extension. Catch spoofed extensions, mismatched MIME types, and executables disguised as images.

Geography & Mapping Tools 3

WKT GeoJSON Converter

Free WKT GeoJSON converter: convert WKT, EWKT and PostGIS output to/from GeoJSON FeatureCollection in WGS84. Validate and visualize geometries online.

GeoJSON Viewer

Free GeoJSON viewer: validate RFC 7946 structure and visualize points, lines and polygons on an interactive map with a WGS84 bounding box readout.

GeoJSON Validator

Free RFC 7946 GeoJSON validator and repair tool. Check syntax, fix polygon winding order (right-hand rule), close rings, validate WGS84 bounds, and reduce coordinate precision.

Social Media Tools 1

Hashtag Analyzer

Audit hashtags by frequency, length, topic and duplicates, flag overused tags against Instagram/TikTok limits, build rotation sets, and export a CSV.

Text Tools 1

Text Difference

Free online diff tool to compare two texts side by side. See additions, deletions, and a similarity match percentage by line, word, or character.