Developer Tools
Everyday developer utilities — formatters, encoders, generators, and testers — with no server round-trip, so sensitive strings and payloads never leave your machine.
JSON Formatter
Format, validate, and minify JSON.
CSV ⇄ JSON Converter
Convert CSV to JSON or JSON to CSV.
Base64 Encoder/Decoder
Encode or decode Base64 text.
URL Encoder/Decoder
Encode or decode URL components.
HTML Entity Encoder/Decoder
Encode or decode HTML entities.
Hash Generator
Generate SHA-1/256/384/512 hashes of text.
UUID Generator
Generate random UUID v4 identifiers.
Regex Tester
Test a regular expression against sample text.
Number Base Converter
Convert numbers between binary, octal, decimal, and hex.
IP Subnet Calculator
Calculate network, broadcast, and usable host range from a CIDR block.
Barcode Generator
Generate a Code 128 barcode from text.
CSS Gradient Generator
Design a linear or radial gradient and copy the CSS.
CSS Box Shadow Generator
Design a box shadow and copy the CSS.
CSS Border Radius Generator
Design a per-corner border radius and copy the CSS.
Meta Tag Generator
Generate SEO and Open Graph meta tags with a live preview.
Unit Converter
Convert length, weight, temperature, and data units.
Timestamp Converter
Convert Unix epoch time to and from a readable date.
Guides & articles
SHA-256 Hash Explained: What It Is and When to Use It
What a SHA-256 hash is, why one changed letter changes everything, how it differs from encryption, and how to generate SHA hashes free in your browser.
Unix Timestamps Explained: Epoch Time to Date and Back
What a Unix timestamp is, why it starts in 1970, seconds versus milliseconds, time zones, and the 2038 problem. Convert epoch time free in your browser.
CSS Gradients, Shadows and Border Radius, Explained
Learn the syntax behind linear-gradient, box-shadow and border-radius, with the values to start from and free generators to preview and copy the CSS.
CSV vs JSON: When to Use Each Format (and How to Convert)
CSV and JSON solve different problems. Learn which fits your data, where each breaks down, and how to convert between them without losing information.
WCAG Color Contrast Ratio Explained: AA vs AAA
What a contrast ratio measures, the 4.5:1, 3:1 and 7:1 WCAG thresholds, and how to check a color pair so light gray text does not fail accessibility.
Base64 Encoding: What It Does and Why It Is Not Security
Base64 turns binary data into plain text so it can travel through text-only systems. It protects nothing. Here is how it works and when to use it.
UUID v4 Explained: How Random IDs Avoid Collisions
What a UUID guarantees, why version 4 is the common default, how unlikely a collision really is, and when a UUID is the wrong choice for your database.
How to Test a Regex Online Before You Ship It
A regex that looks right can still match too much, too little, or hang. Test it against real inputs in your browser before it reaches production.
Why Minified JSON Is Hard to Debug (and How to Fix It)
Minified JSON is great for machines and painful for people. Learn to format, validate and minify JSON, and spot the usual syntax errors fast.
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Frequently asked questions
- Is it safe to paste API keys or secrets into these tools?
- Processing happens entirely in your browser with no network calls, so nothing you paste is transmitted. Still, treat any tool as you would a local script when handling secrets.
- Do these tools work offline?
- Once the page is loaded, most tools continue to work without an internet connection since there is no backend dependency.