I spent the weekend building free developer tools and ended up with 50. All run 100% in your browser — no signup, no tracking, no server uploads. Here is the complete list.
Formatters & Encoders
- JSON Formatter — Beautify, validate, minify, tree view, JSON to YAML/CSV
- HTML Formatter — Prettify and minify HTML with syntax highlighting
- JavaScript Formatter — Beautify and minify JS with ES6+ support
- SQL Formatter — Format SQL queries with keyword highlighting
- XML Formatter — Format, validate, and tree-view XML
- Base64 Encoder/Decoder — Text, files, and image preview
- URL Encoder/Decoder — With URL parser and query builder
- Image to Base64 — Convert images to data URIs
Generators
- UUID Generator — v1, v4, v7, ULID, Nano ID, bulk generate
- Hash Generator — MD5, SHA-1, SHA-256, SHA-512, HMAC
- QR Code Generator — URL, WiFi, vCard, email, custom colors
- Password Generator — Cryptographic, passphrase mode, strength meter
- Barcode Generator — Code 128, EAN-13, UPC-A, batch mode
- Lorem Ipsum Generator — Multiple styles including tech and business
Code & Testing
- Regex Tester — Live highlighting, flags, replace mode, cheat sheet
- cURL to Code — Convert to Python, JS, PHP, Go, Node.js
- Diff Checker — Side-by-side comparison with word-level highlighting
- Cron Builder — Visual scheduler with next 5 execution times
- Markdown Editor — Live preview with toolbar
- JSON/CSV Converter — Convert between formats with nested flattening
Inspectors
- JWT Decoder — Decode header, payload, check expiration
- Timestamp Converter — Unix to human, all timezones, live clock
Image Tools
- Image Compressor — Batch compress PNG, JPG, WebP
- Image Resizer — Social media presets, aspect lock
- Background Remover — AI-powered background removal
- Beauty Filters — 8 adjustments + 8 presets
- Image Enhancer — Auto-enhance, crop, rotate, undo/redo
- Passport Photo Maker — US/UK/EU sizes, print sheet
- Image Format Converter — PNG, JPG, WebP, ICO
- Image to PDF — Multiple images to single PDF
- Favicon Generator — All sizes + HTML code snippet
PDF Tools
- PDF Merge — Combine multiple PDFs, drag to reorder
- PDF Compress — 3 compression levels, batch mode
SEO & Web
- Meta Tag Generator — SEO + social tags with live preview
- Robots.txt Generator — Visual builder + URL tester
- Open Graph Preview — See how links look on 6 platforms
- SSL Checker — Certificate details, grade, warnings
- IP Lookup — Your IP, geolocation, ISP info
Text Tools
- Word Counter — Words, chars, reading time, keyword density
- Case Converter — 12 formats: camelCase, snake_case, etc.
Design
- Color Converter — HEX, RGB, HSL, CMYK + contrast checker
- CSS Gradient Generator — Visual builder with presets
Calculators
- Unit Converter — 10 categories, 100+ units
- Percentage Calculator — 5 modes + tip calculator
- Age Calculator — Zodiac, milestones, fun facts
- Loan Calculator — EMI, amortization, comparison
- BMI Calculator — BMR, ideal weight, calorie needs
Productivity
- Pomodoro Timer — Focus timer with task list
- Typing Speed Test — WPM, accuracy, live graph
- Invoice Generator — Professional invoices, print to PDF
All tools: theappsfirm.com/tools
Everything is client-side (your data never leaves your browser), free forever, no signup needed.
We are also launching on Product Hunt tomorrow (April 14) — would love your support!
What tools would you add to this list? Let me know in the comments.
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