Free Online Developer Tools

20 free browser-based developer tools — no sign-up, no server uploads, all processing happens in your browser.

Developer Tools

Regex Tester & Debugger — Free Online Tool

Test and debug regular expressions with real-time matching, live highlighting, capture groups, and a built-in cheatsheet. Free regex tester with flags support (g, i, m, s)

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Developer Tools

JWT Decoder & Debugger

Decode and debug JSON Web Tokens online. Verify HS256 & RS256 signatures, check expiration, inspect header & payload claims. 100% client-side.

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Developer Tools

Diff Checker

Compare two texts and find differences with unified and side-by-side views

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Developer Tools

SQL Formatter & Beautifier

Format, beautify, and minify SQL queries online. Supports MySQL, PostgreSQL, SQLite, SQL Server, Oracle dialects with configurable indentation and keyword casing

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Developer Tools

HTML Beautifier & Formatter

Beautify, format, and minify HTML with proper indentation and void element handling

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Developer Tools

XML Formatter & Validator

Format, validate, beautify, and minify XML online. Syntax highlighting with line numbers, well-formed XML checking with error location, and download as .xml file.

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Developer Tools

JavaScript Minifier & Beautifier

Minify and beautify JavaScript with safe string, template literal, and regex preservation

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Developer Tools

Cron Expression Parser

Parse cron expressions into human-readable schedules with next run times and syntax reference

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Developer Tools

Cron Expression Generator

Build cron expressions visually with dropdowns, preset templates, human-readable descriptions, and next run time previews. Reverse-parse any cron expression

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Developer Tools

YAML Formatter & Beautifier

Format, beautify, minify, and sort YAML with proper indentation for Kubernetes, Docker, and config files

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Developer Tools

TOML Formatter & Validator

Format, beautify, minify, sort, and validate TOML files for Cargo.toml, pyproject.toml, and configs

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Developer Tools

IP Address Lookup & Subnet Calculator

Find your public IP with geolocation, look up any IP address, and calculate subnets with CIDR notation

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Developer Tools

Unix Timestamp Converter & Epoch Tool

Convert Unix timestamps to human-readable dates and back. Live counter, timezone selector, milliseconds toggle, and common timestamps reference table

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Developer Tools

HTTP Status Codes Reference

Complete HTTP status codes reference. Search all HTTP response codes from 100 to 511 with descriptions, common use cases, and category filters. Find what 404, 500, 301, 429 and every other status code means

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Developer Tools

Chmod Calculator

Interactive Unix file permission calculator. Convert between numeric (755, 644) and symbolic (rwxr-xr-x) permissions with checkboxes, common presets, and ready-to-copy chmod commands

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Developer Tools

HTTP Headers Analyzer

Parse, categorize, and audit HTTP headers with plain-English explanations, security scoring, and export as curl or JSON. Paste raw headers from DevTools or curl.

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Developer Tools

Markdown to HTML Converter

Convert Markdown to clean HTML online. Live preview, raw HTML view, copy button. Supports headings, tables, code blocks, lists, links, images, blockquotes, horizontal rules. 100% client-side.

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Developer Tools

Open Graph & Meta Tag Generator

Free Open Graph and meta tag generator. Create og:title, og:description, og:image, Twitter Card tags and more. Live preview shows exactly how your page looks when shared on Facebook, Twitter/X, LinkedIn, Discord, and Slack.

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Developer Tools

Open Graph & Meta Tag Generator

Generate Open Graph and Twitter Card meta tags instantly. Preview how your page looks when shared on social media. Copy ready-to-paste HTML.

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Developer Tools

Cron Expression Generator

Free online cron expression generator. Visually build cron schedules with minute/hour/day/month/weekday selectors. See human-readable description and next 5 run times instantly.

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