All Tools
16 free, private developer tools that run entirely in your browser. No sign-up, no data uploads, no tracking. Pick a tool and get to work.
Developer Tool Collection
Every tool below processes data 100% client-side using your browser's built-in APIs. Your JSON, code, images, and PDFs never leave your device. Bookmark this page for quick access to the full collection.
JSON Explorer
DevToolBox JSON Explorer lets you format, visualize, and compare JSON data with an interactive tree view. Paste raw JSON and instantly see it formatted with syntax highlighting.
Use ToolDiff Checker
DevToolBox Diff Checker compares two blocks of text or code and highlights every difference at the character level. View diffs side by side or inline.
Use ToolRegex Playground
DevToolBox Regex Playground lets you test regular expressions in real time. See matches highlighted as you type, inspect capture groups, get plain-English explanations of your patterns, and generate ready-to-use code snippets for JavaScript, Python, and more.
Use ToolCron Visualizer
DevToolBox Cron Visualizer helps you build, test, and understand cron expressions. Enter a cron expression or use the visual builder, and see the next execution times on a timeline with a plain-English explanation of what the schedule does.
Use ToolCSS Generators
DevToolBox CSS Generators give you visual editors for common CSS patterns. Adjust sliders and see results in real time.
Use ToolQR Code Generator
DevToolBox QR Generator creates QR codes instantly from any text, URL, or data. Customize foreground and background colors, adjust size, and download in PNG or SVG format.
Use ToolImage Compressor
DevToolBox Image Compressor shrinks image file sizes without noticeable quality loss. Drop images in, adjust quality, resize dimensions, and export in JPG, PNG, or WebP.
Use ToolColor Palette
DevToolBox Color Palette helps designers generate beautiful color palettes, convert between color formats (HEX, RGB, HSL), and check WCAG accessibility contrast ratios. Create complementary, analogous, and triadic color schemes instantly.
Use ToolOG Preview
DevToolBox OG Preview shows you exactly how your website appears when shared on Google, Twitter, Facebook, Slack, and Discord. Enter your meta tags and see live previews across all platforms.
Use ToolTimestamp Converter
DevToolBox Timestamp Converter converts between Unix timestamps (epoch seconds/milliseconds) and human-readable dates. Compare times across timezones, see relative time differences, and format dates in ISO 8601, RFC 2822, and custom formats.
Use ToolPDF Tools
DevToolBox PDF Tools let you merge multiple PDFs, split pages, compress file size, rotate pages, add watermarks, and convert images to PDF — all in your browser. Your files are never uploaded to any server.
Use ToolJWT Decoder
DevToolBox JWT Decoder lets you paste any JSON Web Token and instantly view the decoded header, payload, and signature. See all claims, check expiration status, and inspect the token structure.
Use ToolBase64 Encoder
DevToolBox Base64 Encoder converts text and files to and from Base64 encoding. Supports standard and URL-safe Base64.
Use ToolURL Encoder
DevToolBox URL Encoder lets you encode and decode URLs using encodeURIComponent or encodeURI. Parse any URL into its components (protocol, host, path, query parameters).
Use ToolMarkdown Preview
DevToolBox Markdown Preview gives you a split-pane editor with live rendering. Write markdown on the left, see formatted HTML on the right.
Use ToolHash Generator
DevToolBox Hash Generator computes cryptographic hashes instantly. Enter text or drop a file to get MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes simultaneously.
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