Developer Encoding & Decoding Tools
20 tools in this collection — free, instant, and private in your browser.
Developer encoding and decoding tools are the workbench utilities that every web developer, API designer, and security engineer reaches for daily. At their core, these tools translate data between the raw binary or byte-level representation computers use internally and the text-safe or human-readable forms required by browsers, HTTP requests, databases, and third-party APIs.
Understanding a few foundational concepts makes every tool here easier to use. Character encoding determines how text is stored as bytes; UTF-8 is the universal standard on the web, and the String Byte Length Calculator helps you see exactly how many bytes a string occupies once encoded. Base64 maps binary data to a 64-character alphabet so it can travel safely inside JSON, email bodies, or data URIs — the Base64 Encoder and Decoder handle both directions. URL encoding (also called percent-encoding) replaces characters that carry special meaning in a URL — spaces, ampersands, equals signs — with their hexadecimal escape sequences, which is what the URL Encoder and Decoder manage.
HTML entity encoding serves a similar purpose for markup: the HTML Entity Encoder converts characters like <, >, and & into safe entity references so they display correctly without being interpreted as tags. The corresponding Decoder reverses this for reading or debugging server responses. For API work, the JWT Payload Decoder lets you inspect the claims inside a JSON Web Token without a library or server round-trip, while the Query String to JSON Converter turns a raw URL query string into a structured object you can read at a glance.
When working with source code or configuration files, the JSON Validator and JSON Minifier keep your data clean and compact, and the Regex Special Character Escaper saves time by automatically inserting the backslashes regex engines require. The URL Slug Generator normalizes titles and phrases into URL-safe slugs, removing accents and replacing spaces with hyphens — essential for CMS integrations and routing logic.
- Use the Base64 tools for binary payloads, images in data URIs, and HTTP Basic Auth headers.
- Use the URL Encoder / Decoder when constructing or debugging query parameters and redirect URLs.
- Use the HTML Entity tools when sanitizing user input or inspecting server-rendered HTML.
- Use the JWT Payload Decoder to quickly verify token claims during API development or troubleshooting.
- Use the JSON tools to validate API responses and strip whitespace before storing or transmitting JSON.
Whether you are building a REST client, debugging a webhook, or preparing text for safe storage, these tools eliminate the manual error-prone work of encoding conversions and let you stay focused on the logic that matters.
All developer encoding & decoding tools
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| Tool | What it does |
|---|---|
| ASCII Code to Text Converter | Convert space-separated ASCII (char code) values back to text. Free, instant. |
| Base64 Decoder | Decode any Base64 string back to plain text instantly. Free, no signup. |
| Base64 Encoder | Encode any text to Base64 instantly in your browser. Free, no signup. |
| Bytes to Human Readable Converter | Convert a byte count to a human-readable size like KB, MB, GB. Free, instant. |
| Date to Unix Epoch Converter | Convert any UTC date and time to a Unix timestamp (epoch seconds). Free, instant. |
| HTML Entity Decoder | Decode HTML entities back into readable characters. Free, instant. |
| HTML Entity Encoder | Encode special characters into HTML entities for safe display in HTML. Free, instant. |
| JSON Minifier | Minify JSON by removing whitespace and formatting. Free, instant, runs in your browser. |
| JSON Validator | Validate JSON syntax instantly. Get clear error messages for invalid JSON. Free. |
| JWT Payload Decoder | Decode and inspect a JWT token's header and payload instantly. Free, runs in your browser. |
| Lines of Code Counter | Count total lines, non-empty lines, and blank lines in code or text. Free, instant. |
| Query String to JSON Converter | Convert a URL query string to a JSON object instantly. Free, no signup. |
| Regex Special Character Escaper | Escape special regex characters in a string so it can be used as a literal pattern. Free, instant. |
| String Byte Length Calculator | Calculate the byte length of any string in UTF-8 encoding. Free, instant. |
| Text to ASCII Code Converter | Convert text to ASCII (char code) values. Free, instant, no signup. |
| URL Decoder | Decode a percent-encoded URL string back to readable text. Free, instant. |
| URL Encoder | Percent-encode a string for safe use in URLs. Free, instant, no signup. |
| URL Slug Generator (Slugify) | Convert any text to a URL-friendly slug. Free, instant, no signup. |
| Unix Epoch to Date Converter | Convert a Unix timestamp (epoch) to a human-readable UTC date and time. Free, instant. |
| Whitespace Remover & Text Minifier | Remove extra whitespace, blank lines, and leading/trailing spaces from text. Free, instant. |
Frequently asked questions
- What is the difference between URL encoding and Base64 encoding?
- URL encoding (percent-encoding) converts characters that have special meaning in a URL into a percent sign followed by two hex digits, so a space becomes %20. It is designed specifically for URLs and keeps the text mostly human-readable. Base64 encoding converts arbitrary binary data into a 64-character alphabet of letters, digits, plus, and slash. It is used when binary content must travel inside a text-only format such as JSON or email, not specifically for URLs.
- Is it safe to decode a JWT token in the browser?
- Decoding a JWT only reads the payload -- it does not verify the cryptographic signature. The JWT Payload Decoder is safe to use for inspecting claims during development or debugging, but you should never treat the decoded content as trusted data in a production application without also verifying the signature on a server using your secret or public key.
- Why does a string have more bytes than characters?
- Many characters outside basic ASCII -- accented letters, emoji, Chinese characters -- require two to four bytes in UTF-8. The String Byte Length Calculator shows you the byte count rather than the character count, which matters for database column limits, HTTP Content-Length headers, and any system that enforces byte-based size constraints rather than character-based ones.