Free Online JSON Validators, RegEx Testers & Code Linters
Validate JSON syntax, test regular expressions with live match groups, lint package.json dependencies, and detect code obfuscation.
Available Tools (17)
View in Full Directory →SSL / X.509 Certificate Inspector
Inspect and decode PEM / CRT SSL certificates to view Common Name, Issuer, SANs, and Expiry.
CRC32 Checksum Calculator
Compute standard 32-bit CRC32 checksums (IEEE 802.3) in Hexadecimal, Decimal, and Binary.
FAQ Page JSON-LD Schema Generator
Build interactive FAQPage JSON-LD structured data for Google Search rich snippets.
Hash & Checksum Comparator
Compare two cryptographic hashes or file checksums with instant character-by-character integrity verification.
HowTo Step-by-Step Schema Generator
Build structured @type: 'HowTo' JSON-LD schema markup with step titles, descriptions, and supplies for Google.
HTTP Headers Parser & Security Audit
Parse raw HTTP request and response headers into structured JSON and perform an instant security audit.
Zero-Width & Invisible Character Detector
Detect, reveal, and remove hidden zero-width spaces, soft hyphens, and invisible Unicode control characters.
JavaScript Obfuscation & Entropy Analyzer
Detect code obfuscation, packed scripts, high Shannon entropy, eval() execution, and suspicious variable patterns in JavaScript.
JSON to Zod Schema Generator
Convert JSON objects into strict TypeScript Zod validation schemas with automatic type inference.
JSON Validator
Check if your JSON data is valid and well-formed.
Meta Robots & X-Robots-Tag Generator
Generate granular HTML meta robots directives (noindex, nofollow, nosnippet) and HTTP X-Robots-Tag response headers.
Open Graph & Meta Tag Generator
Generate HTML meta tags, OpenGraph (Facebook/LinkedIn), and Twitter Cards.
package.json Validator & Dependency Analyzer
Validate package.json syntax, check npm semver version ranges, and detect missing required fields.
RegEx Token Builder & Cheatsheet Tester
Interactive regular expression tester with quick-click token inserts for lookaheads, capture groups, and anchors.
Regex Tester
Test regular expressions with live match results.
Robots.txt Generator
Visual builder for search engine crawler directives and sitemap declarations.
WebSocket & JSON-RPC Frame Inspector
Construct, validate, and simulate JSON-RPC 2.0 WebSocket messages and client connection scripts.
Deep Syntax Validation & Structural Code Integrity
Catching syntax errors, unbalanced brackets, invalid schema structures, and dangerous wildcard dependencies before deploying code prevents costly downtime.
Our validation suite provides granular line-by-line error pointers, human-readable explanations, and one-click automated syntax fixes.
Interactive RegEx token builders and cheatsheets help developers construct, test, and debug complex regular expressions with live visual capture groups.
Frequently Asked Questions
Everything you need to know about our free client-side validation & syntax checkers.
Explore Other Categories
All Categories (9) →Data & Schema Converters
Convert, format, transform, and structure data between JSON, CSV, XML, YAML, SQL, TSV, TOML, and database schemas instantly in your browser.
Text & String Utilities
Format, count, sanitize, sort, filter, deduplicate, and analyze text strings with zero latency and complete privacy.
Calculators & Math Tools
Compute percentages, conversions, bandwidth transfer times, statistical distributions, loan payments, and binary math instantly.