Every developer needs quick tools that just work — no install, no signup.
I've been building a collection of 100% client-side developer utilities that run entirely in your browser. Zero data sent to servers. Here are my favorites:
Text & Data Tools
1. JSON Formatter & Validator
Paste messy JSON, get it beautifully formatted with syntax highlighting. Validates on the fly.
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2. Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 back. Handles UTF-8 properly.
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3. JSON ↔ CSV Converter
Convert JSON arrays to CSV and back. Great for quick data transformations.
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4. Markdown Table Generator
Visual table builder that outputs clean Markdown. Drag to resize columns.
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5. Word Counter & Text Analyzer
Real-time character, word, sentence counts plus reading time and word frequency.
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Security & Encoding
6. Password Generator
Cryptographically secure passwords using Web Crypto API. Configurable length and character sets.
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7. Hash Generator (MD5, SHA-1, SHA-256, SHA-512)
Generate hashes for any text. Compare hashes side by side.
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8. UUID Generator
Generate v4 UUIDs instantly. Bulk generation support.
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Developer Utilities
9. Regex Tester & Explainer
Test regular expressions with real-time matching and plain-English explanations.
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10. Cron Expression Parser
Parse and explain cron expressions in human-readable format.
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11. Color Converter
Convert between HEX, RGB, HSL. Visual preview included.
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12. QR Code Generator
Generate QR codes for any text or URL. Download as PNG.
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13. Text Diff Checker
Compare two texts side by side with highlighted differences.
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14. Base64 JWT Decoder
Decode JWT tokens and inspect headers and payloads.
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15. Invoice Generator
Create professional invoices and download as PDF.
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All tools are open source, run 100% in your browser, and require no signup.
Full collection: Profiterole Developer Tools
What browser-based tools do you use daily? Drop them in the comments!
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