Fast, privacy-first utilities for JSON, CSV, strings and cryptography.
Everything runs locally in your browser.
JSON Validator
Validate, prettify, and minify JSON data
JSON Key Counter
Count keys and array elements in JSON
JSON → CSV
Convert JSON arrays to CSV format
CSV -> JSON (Drag & Drop)
Convert CSV files to JSON format
String Length Counter
Count characters, bytes, and lines
Base64 Encode/Decode
Convert strings to/from Base64
HMAC Signature Generator
Generate cryptographic signatures
Why Choose Json Nest?
- 100% Client-Side: Your data never leaves your browser. No uploads, no tracking, full privacy.
- Developer Friendly: Tools designed for everyday JSON, CSV, and encoding tasks.
- Fast & Lightweight: Runs instantly without waiting for servers or APIs.
- Cross-Platform: Works on desktop and mobile, with responsive design.
- Free Forever: All tools are completely free to use.
Frequently Asked Questions
What makes Json Nest different?
Unlike many online utilities, Json Nest never sends your data to a server. Everything runs locally in your browser, ensuring maximum privacy and speed.
Can I use these tools offline?
Yes. Once a page is loaded, most tools will work without internet access because they rely only on your browser’s JavaScript engine.
Is Json Nest free to use?
Yes, all tools are 100% free. We support the site through ads and community contributions.
Who is Json Nest for?
Developers, data analysts, students, and anyone working with structured data, strings, or cryptographic operations.