Free Online Developer Tools — JSON, Base64, URL Encoding & More
Developer tools are the utilities that software engineers, web developers, DevOps engineers, and data professionals reach for when debugging, building, or testing. Formatting a raw API response, decoding a Base64 string, encoding a URL parameter, validating JSON syntax, or generating a secure random password — these are tasks that come up every day, and having a fast, no-install browser-based tool makes the workflow significantly smoother.
Our developer tool collection is built specifically for people who know what they are doing and need the tool to get out of the way. No ads cluttering the interface, no requiring you to log in, no sending your data to a third-party server. Your JSON, Base64 strings, URLs, and passwords are all processed locally in your browser.
These tools are particularly useful when you are working across environments — debugging an API response on a client's server, reviewing a JWT token from a production log, or encoding a URL parameter while writing documentation. Having a reliable, fast browser tab you can switch to without installing anything is a genuine productivity advantage. CalcDash developer tools are fast-loading, keyboard-friendly, and accurate.
All Developer Tools (12)
JSON Formatter
Format, validate, and minify JSON online. Instantly beautify or compress JSON data with syntax highlighting. Free JSON formatter and validator.
Use JSON Formatter →PopularBase64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings back to plain text online. Free Base64 encoder decoder tool for developers and data analysts.
Use Base64 Encoder / Decoder →URL Encoder / Decoder
Encode or decode URLs and query strings online. Convert special characters to percent-encoding instantly. Free URL encoder decoder for developers.
Use URL Encoder / Decoder →PopularPassword Generator
Generate strong, random passwords instantly. Customize length and character types. Free secure password generator tool for safe online accounts.
Use Password Generator →PopularColor Converter
Convert colors between HEX, RGB, HSL, and HSB online free. Pick colors visually and copy CSS values in any format instantly — no signup needed.
Use Color Converter →Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and times online free. Convert dates to Unix timestamps in seconds or milliseconds instantly.
Use Unix Timestamp Converter →Regex Tester
Test and debug regular expressions online free. Write regex patterns, test against sample text, and see matches highlighted instantly.
Use Regex Tester →JWT Decoder
Decode and inspect JSON Web Tokens online free. View the JWT header, payload, and claims without your secret key — client-side only, no data sent anywhere.
Use JWT Decoder →Markdown to HTML Converter
Convert Markdown to HTML online free with a live preview. Paste any Markdown and copy clean HTML output for websites, CMS platforms, or apps. No install.
Use Markdown to HTML Converter →HTML Entity Encoder & Decoder
Encode HTML special characters to entities and decode HTML entities back to text free online. Convert <, >, &, and " instantly — no signup, browser-based.
Use HTML Entity Encoder & Decoder →UUID Generator
Generate random UUIDs (Universally Unique Identifiers) free online. Create single or bulk UUID v4 values instantly for databases, APIs, and development.
Use UUID Generator →Hash Generator
Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text free online. Verify file integrity and check passwords with instant hash generation.
Use Hash Generator →Frequently Asked Questions
- Are CalcDash developer tools safe to use with real data?
- Yes. All data is processed entirely in your browser using JavaScript — nothing is ever sent to CalcDash servers. You can safely paste production JSON, JWT tokens, credentials, and other sensitive data.
- What is the most common use for the JSON formatter?
- The most common use is formatting (beautifying) minified API responses to make them human-readable for debugging. The second most common use is validating JSON syntax to find errors like trailing commas, missing quotes, or incorrect value types before running code.
- How is Base64 different from encryption?
- Base64 is encoding, not encryption. It converts binary data to ASCII text and is completely reversible by anyone — it provides no security. Encryption (like AES or RSA) uses a secret key to make data unreadable without that key. Never use Base64 to protect sensitive information.
- When should I use URL encoding?
- Use URL encoding (percent-encoding) whenever you include user input, special characters, or non-ASCII text in a URL query parameter. Always encode individual parameter values, not the entire URL, to avoid encoding the structural characters like /, ?, and &.
- How long should a secure password be?
- Security experts recommend 16+ characters for most accounts and 20+ for email and financial accounts. Use all four character sets (uppercase, lowercase, numbers, symbols). A unique password for every site, stored in a password manager, is the most important security habit you can develop.