No Strings Attached
I spent the last month building free tools for developers. No signup walls, no email capture, no premium upsells on these. Just open and use.
Here's the full toolkit — bookmark this article because you'll use at least 3 of these this week.
🛠️ The 10 Tools
1. JSON Formatter & Validator
Paste messy JSON, get beautifully formatted output. Catches errors instantly. Supports minification too.
Use when: Debugging API responses, cleaning config files, preparing data payloads.
2. Base64 Encoder/Decoder
Encode text to Base64 or decode it back. Handles large inputs and binary data.
Use when: Working with API authentication, embedding small images in HTML/CSS, debugging tokens.
3. Secure Password Generator
Generate cryptographically secure passwords with customizable length, character sets, and exclusion rules.
Use when: Creating new accounts, rotating credentials, setting up service accounts.
4. Color Picker & Converter
Pick colors and convert between HEX, RGB, HSL, and CMYK instantly. Includes contrast checker for accessibility.
Use when: Designing UI components, checking WCAG compliance, matching brand colors.
5. Lorem Ipsum Generator
Generate placeholder text in paragraphs, sentences, or words. Control the exact count.
Use when: Building layouts before content is ready, prototyping UIs, filling design mockups.
6. Text Case Converter
Transform text between camelCase, snake_case, kebab-case, PascalCase, UPPER_CASE, and more.
Use when: Naming variables across languages, formatting API keys, normalizing database fields.
7. URL Encoder/Decoder
Encode or decode URLs with full special character support.
Use when: Building query strings, debugging URL parameters, handling special characters in paths.
8. Hash Generator (MD5, SHA)
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from any text input.
Use when: Verifying file integrity, checking password hashes, creating cache keys.
9. Regex Tester
Test regular expressions against sample text with real-time matching and group highlighting.
Use when: Writing validation rules, parsing log files, extracting data from text.
10. Unit Converter
Convert between common units: length, weight, temperature, data size, time.
Use when: Quick conversions without leaving your workflow, API response formatting.
Why I Built These
Every developer wastes time leaving their IDE to use random websites for simple tasks. These tools:
- Run 100% client-side — your data never leaves your browser
- No signup required — just open and use
- Work offline — once loaded, they keep working
- Are completely free — no "upgrade to pro" button
The Technical Stack
If you're curious how I built these:
- Frontend: Vanilla JavaScript (no framework bloat for simple tools)
- Hosting: GitHub Pages (free, fast CDN)
- Styling: Minimal CSS, mobile-responsive
- Privacy: Zero server-side processing, zero analytics tracking
Total hosting cost: $0/month.
Want to Build Your Own?
I compiled everything I learned building these tools into a PDF guide:
📚 The Developer's API Cheat Sheet Collection — 20 free APIs you can use to build tools like these in a weekend.
🆓 10 AI Prompts That Save Me 5 Hours Every Week — Free lead magnet with my best AI-assisted coding prompts.
Bookmark This
https://nguyenminhduc9988.github.io/free-tools-hub/
That's the permanent URL for the full toolkit. I add new tools weekly — last month added: QR code generator, Markdown preview, and HTML entity encoder.
What tools should I build next? Drop a comment.
If you found this useful, follow me for weekly developer productivity content. I publish new tools, cheat sheets, and tutorials every week.
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