Free Developer Tools Online — 23 Tools, No Signup, 100% Private
23 free developer tools that run entirely in your browser. Format APIs, preview JSON, generate QR codes, test regex, convert encodings, debug CSV, rename files, visualize folders, and more — no server uploads, no signup, no watermarks. Unlike regex101 and diffchecker.com, your data never leaves your device.
JSON → UI Preview
Visualize JSON as an interactive collapsible tree with type badges and search.
API Response Formatter
Format raw API responses with status badges, headers, and error details.
Code Screenshot Generator
Create beautiful code screenshots with 8 themes and PNG export.
Markdown → Beautiful Docs
Render Markdown as styled documentation with syntax highlighting.
Fake Data Generator
Generate realistic dummy data — users, emails, addresses — export as CSV, JSON, or SQL.
Email Signature Generator
Create professional email signatures with custom colors and copy-paste HTML output.
SVG Optimizer
Clean and optimize SVG files — remove bloat from Figma/Illustrator exports with 30+ plugins.
QR Code Generator
Generate QR codes for URLs, text, WiFi, vCards, and emails. Custom colors and SVG export.
Barcode Generator
Generate barcodes in 7 formats — Code128, EAN-13, UPC-A, ITF-14, MSI, Codabar. PNG/SVG.
Password Generator
Generate strong, crypto-secure passwords with bulk export. Customizable length and character sets.
JSON ↔ CSV Converter
Convert between JSON and CSV formats with custom delimiters. Bidirectional, instant.
Favicon Generator
Generate .ico, multi-size PNGs, apple-touch-icon, and manifest.json from any image.
Color Picker & Palette
Pick colors with hex/RGB/HSL conversion, WCAG contrast checker, and image palette extraction.
Word Counter
Count words, characters, sentences. Check reading time, keyword density, and SEO metrics.
Base64 Encode / Decode
Encode and decode Base64, URL encoding, and HTML entities — 6 tools in one.
Regex Tester
Test regular expressions with real-time matching, group highlighting, and cheat sheet.
CSS Gradient Generator
Build CSS gradients visually — linear, radial, conic with 10 presets and copy-paste CSS.
Lorem Ipsum Generator
Generate placeholder text as paragraphs, sentences, or words. Start with Lorem option.
Diff Checker
Compare text, JSON, or images side by side with syntax-highlighted diff — no size limit.
Multi-Format Converter
Convert any file to Text, Table, JSON, or Images — all in one interface. One upload, four outputs.
CSV Visual Debugger
Upload CSV and instantly find duplicates, empty values, type mismatches, and column issues.
Bulk File Renamer
Rename multiple files at once using numbering, date, pattern, or find-and-replace rules.
Folder Structure Visualizer
Drag & drop a folder to see an interactive tree view with collapsible nodes and unused file detection.
Why Developers Choose Toolsz
100% Client-Side & Private
Your JSON, API tokens, regex patterns, and source code never leave your browser. Unlike regex101, diffchecker.com, and Mockaroo, nothing is uploaded to any server.
No Premium, No Limits
Mockaroo limits rows, diffchecker.com limits file size, QR Code Monkey gates SVG export. Toolsz has zero restrictions — every feature is completely free with no signup.
23 Tools, One Workflow
No more switching between regex101, carbon.now.sh, and 5 other sites. Toolsz puts every dev tool you need in one place — with consistent UI and no accounts.