ZeroData Tools
Tools
JSON Formatter Format and validate JSON instantly with no uploads, no server calls, and no stored data. JSON Validator Validate JSON instantly before deploys with local processing and zero server calls. YAML Validator Validate YAML files and catch indentation errors instantly with no uploads or backend processing. Base64 Encoder Encode or decode Base64 strings instantly with zero uploads. URL Encoder Encode and decode query parameters locally for APIs, redirects, and forms. HTML Formatter Pretty-print messy markup and inspect structure without exposing page code. CSS Minifier Shrink stylesheets for production with browser-only processing and instant output. JavaScript Beautifier Reformat dense JavaScript into readable code locally for debugging.
Blog

ZeroData Tools Blog

Deep dives into developer privacy, client-side security, and why your data should never leave your browser.

Security

What Is the JWT exp Claim? Understanding Token Expiration

Learn what the exp claim in a JWT does, how Unix timestamps control token expiration, common bugs, and how to check expiry safely in your browser.

· 7 min read
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Security

Why You Should Never Upload .env Files Online

Your .env file contains database passwords, API keys, and encryption secrets. Here's why online formatters are a risk and how to format .env files locally.

· 6 min read
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DevOps

How to Fix Common CORS Errors: A Developer's Guide

Understand why CORS errors happen, how preflight requests work, and how to fix them in Express, Flask, Spring Boot, and Nginx with correct headers.

· 8 min read
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DevOps

Docker Run vs Docker Compose: When to Use Each

Compare docker run and docker-compose for container workflows. Learn when to use each and how to convert between them safely.

· 7 min read
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Privacy

Best Privacy-First Developer Tools in 2026

A curated list of free, browser-based developer tools that never upload your data. JSON formatters, JWT debuggers, password generators, and more.

· 8 min read
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DevOps

How to Write a Cron Expression — From Basics to Every-5-Minute Schedules

Learn cron expression syntax step by step with real examples for every 5 minutes, daily, weekly, and monthly schedules.

· 7 min read
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Security

JWT Debugging Without Exposing Your Tokens Online

Why pasting JWTs into online debuggers is a security risk and how client-side tools let you inspect tokens without uploading them.

· 6 min read
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Security

How to Generate Strong Passwords in the Browser Without Uploading Anything

Why browser-based password generation is safer than server-side tools and how crypto.getRandomValues makes it cryptographically strong.

· 6 min read
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Security

Why Your SQL Formatter Shouldn't Upload Your Queries

Most online SQL formatters upload your queries to a remote server. Here's why that's a security risk and how client-side formatting protects your database schema.

· 6 min read
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