Tester Tools

Regex Tester

Test regular expressions against sample text with match highlighting.

Diff Checker

Compare two texts and see the differences highlighted line by line.

Word Counter

Count words, characters, sentences, paragraphs, and estimate reading time.

JSON Path Finder

Explore JSON structure and find paths to every value.

Word-Level Diff

Compare texts and highlight differences at the word level.

Open Graph Preview

Preview how your page looks when shared on Facebook, LinkedIn, and X.

User Agent Parser

Parse user agent strings to detect browser, OS, and device type.

SSL Certificate Checker

Check SSL certificate validity, issuer, expiration, and protocol for any domain.

Typing Speed Test

Test your typing speed (WPM) and accuracy with random programming quotes.

JSON Schema Validator

Validate JSON data against a JSON Schema with detailed error reporting.

JWT Expiry Checker

Check if a JWT token is expired and show remaining time until expiration.

JSON Diff

Compare two JSON documents structurally and see added, removed, and changed values.

JSON Query

Query JSON with dot paths, array indexes, and wildcards to extract values.

JWT Signature Verify

Verify a JWT HS256/384/512 signature against a secret, locally.

HTTP Header Analyzer

Paste HTTP response headers to see what each one does and which security headers are missing.

Text Statistics

Analyze word count, reading time, reading ease, grade level, and keyword density.

UUID Inspector

Validate a UUID and detect its version, variant, and v1 timestamp.

URL Parser

Break a URL into protocol, host, path, query, and hash components.

JSON Payload Validator

Validate a JSON payload and see size, key count, and nesting depth.

Color Contrast Checker

Check WCAG AA/AAA color contrast ratios for accessibility.

Color Blindness Simulator

Preview how a color looks under common color-vision deficiencies.

3-Way Diff

Compare two versions against a common base and spot merge conflicts.

Dockerfile Linter

Check a Dockerfile for best-practice issues like unpinned tags and root user.

ASN.1 / DER Parser

Parse DER-encoded ASN.1 (certificates, keys) into a readable tree.

WebAuthn Tester

Check WebAuthn support and run a passkey registration ceremony.