About encodedecode.app

Free developer encoding & decoding tools. No signup, no upload, no limits.

What is encodedecode.app?

encodedecode.app is a collection of free developer tools for encoding, decoding, and converting data. All tools are instant, private, and run entirely in your browser. There is no server processing your data — ever. Whether you are decoding a JWT during API debugging, verifying a file checksum, or converting a hex color for a CSS variable, the goal is to give you the answer in under five seconds with zero friction.

Why we built it

Developer tools on the web have a persistent problem: they are often slow, cluttered with ads, require accounts, or silently send your data to a remote server. Pasting a JWT containing user data into a random online decoder is a real security risk. Uploading a sensitive file to an online Base64 converter is a data leak waiting to happen.

encodedecode.app was built with a single constraint: every operation must run entirely in the browser using only native APIs. No npm encoding libraries, no server-side processing, no data collection. You can open DevTools, switch to the Network tab, and use any tool on this site — you will see zero outbound requests triggered by the encoding or decoding operation itself.

Who uses these tools

Web and backend developers use the Base64, URL, HTML, JWT, and Hash tools daily during API integration, debugging, and security testing. Decoding a JWT to check claims and expiry, percent-encoding a query parameter, or generating a SHA-256 checksum are tasks that come up constantly in development workflows.

DevOps and sysadminsuse the Cron expression generator to build and verify scheduled job syntax before deploying to production, and the Binary & Hex converter for reading protocol dumps and memory addresses.

Designers and front-end engineers use the Color converter to translate between HEX, RGB, HSL, and CMYK formats and to verify accessibility contrast ratios against WCAG standards.

Students learning web development use the tools to understand how encoding systems work in practice — seeing “Hello” become “SGVsbG8=” in Base64, or watching a cron expression parse into a plain-English schedule, makes abstract concepts immediately concrete.

Tools available

Base64 Encode / Decode

Encode text and files to Base64, decode Base64 strings, URL-safe variant, image preview

URL Encode / Decode

Percent-encode URL components and full URLs, decode percent-encoded strings

HTML Encode / Decode

Convert HTML special characters to entities — basic, extended, and numeric modes

JWT Decoder

Decode JSON Web Tokens, inspect all claims, check expiry with human-readable timestamps

Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text or files

Base64 to Image

Render Base64 strings as images with instant preview and format detection

Image to Base64

Convert image files to Base64 data URIs for HTML, CSS, and API use

Binary & Hex

Convert text to binary and hexadecimal and back, with auto-format detection

ROT13 / Caesar

Apply ROT13 or any Caesar cipher shift with live letter mapping

Morse Code

Translate text to Morse code and back, with audio playback at adjustable speed

Cron Expression

Build and decode cron expressions with plain-English descriptions and next run times

Regex Tester

Test regular expressions with live highlighting, match list, and capture group display

Color Converter

Convert between HEX, RGB, HSL, and CMYK with WCAG contrast checker

Privacy first

Every tool on encodedecode.app processes data exclusively in your browser using only native APIs:btoa(),atob(),encodeURIComponent(),window.crypto.subtle, and the FileReader API. No data is ever transmitted to any server. No encoding library npm packages.

This matters most for sensitive data. A JWT token contains user identity information. A file being hashed may be confidential. A Base64 string may encode an API key or private certificate. With encodedecode.app, none of that data leaves your machine. You can verify this yourself at any time by opening DevTools → Network tab and using any tool — you will see zero outbound requests.

Built for developers

This site is built by developers, for developers. The goal is a tool you can bookmark and reach for every day without friction — no popups, no account requirements, no upload limits, no waiting for server responses. Every tool is instant because all computation happens locally in your browser. The dark mode respects your system preference and persists in localStorage. The URL for each tool is clean and memorable. Everything is designed to get out of your way and give you the answer.