👨‍💻 Developer Toolkit

Free Online Tools for Developers

JSON workspace, JWT decoder, TypeScript generators, Base64, URL encoder, CSS/HTML/JS minifiers, and more. No signup. Runs entirely in your browser.

Developer Essentials

JSON Workspace
Complete JSON toolkit — 15 tools
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JSON Validator
Validate & auto-repair JSON
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JSON to TypeScript
Generate TypeScript interfaces
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JSON Editor
Format, validate, minify, sort
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JWT Decoder
Decode JWT tokens instantly
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Base64 Encoder / Decoder
Encode/decode Base64 & files
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JSON Schema Generator
Generate JSON Schema draft-07
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JSON Repair
Fix broken JSON automatically
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CSS Minifier
Minify CSS for production
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HTML Minifier
Minify HTML for faster pages
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JavaScript Minifier
Minify JS for production
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URL Encoder / Decoder
Encode and decode URL components
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Timestamp Converter
Unix epoch to human-readable date
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Secret Generator
Secure passwords and API keys
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JSON Workspace — 15 Tools in One Place

🛠️ JSON Tools Hub — All 15 tools→✓ JSON Validator & Auto-Repair→TS JSON to TypeScript Interfaces→⊞ JSON Schema Generator (draft-07)→$. JSONPath Tester→🔧 JSON Repair — Fix Broken JSON→

Tools for Other Audiences

✍️ Tools for Bloggers
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📣 Tools for Marketers
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🎓 Tools for Students
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🔍 Tools for SEO Experts
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The Complete Free Developer Toolkit

Multi-Toolkit provides 20+ free developer tools that run entirely in your browser — no server uploads, no account required. The JSON Workspace includes a validator, formatter, minifier, schema generator, JSONPath tester, and converters for CSV, YAML, XML, TypeScript, Python, and Java. Every tool is optimised for speed, keyboard shortcuts, and dark mode.

Frequently Asked Questions

What is the best free JSON validator online?

Multi-Toolkit's JSON Validator at /json-tools/validator is free, fast, and requires no signup. It validates JSON in real-time, shows line-by-line errors, and can auto-repair common issues like trailing commas and single quotes.

How do I decode a JWT token for free?

Use the JWT Decoder at /jwt-decoder. Paste any JWT token to instantly see the decoded header, payload, and verify the token structure. No signup or account required.

How do I generate TypeScript interfaces from JSON?

Use JSON to TypeScript at /json-tools/to-typescript. Paste any JSON object (e.g., from an API response) and it instantly generates TypeScript interface definitions with proper types.

What is the best free online CSS minifier?

The CSS Minifier at /css-minifier removes whitespace and comments from CSS instantly in your browser. No upload, no account, completely free. Also available: HTML and JavaScript minifiers.

Can I generate a JSON Schema from sample data?

Yes. The JSON Schema Generator at /json-tools/schema-generator infers a JSON Schema (draft-07) from any JSON value automatically. It detects types, required fields, and nested structures.