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

Convert Ethereum addresses to EIP-55 checksum format. Validate and format ETH, BSC, Polygon addresses with mixed-case checksums for error detection.

BIP39 Mnemonic

Generate or validate BIP39 seed phrases of 12-24 words for crypto wallets. Verify checksum, derive seed hex, view entropy bits. Client-side and private.

Crypto Address Validator

Validate Bitcoin, Ethereum, Solana, Tron, Litecoin and 30+ blockchain addresses with Base58Check, Bech32 and EIP-55 checksum verification, all in your browser.

Wallet Address Validator

Validate any wallet address offline: Bitcoin Base58Check + Bech32, Ethereum EIP-55, Solana, Tron, Litecoin, Dogecoin, Cardano, Stellar. No API, runs in your 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: view, validate and visualize GeoJSON data on interactive map. Display points, lines, polygons. Check GeoJSON syntax and structure.

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

Analyze hashtags with frequency counting, length analysis, topic grouping, and duplicate detection. Find overused hashtags and optimize your social media strategy.

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.