# Coder

> Encode and decode HTML entities, URLs, Base64, JSON, JWT, and Data URIs — seven tabs, all client-side in the browser, no account.

Source: https://www.jpkc.com/db/en/tools/coder/

## Seven encode/decode tools in one place

Web development throws the same small chores at you again and again: quickly escape a chunk of HTML so the angle brackets stay as text. Encode a query parameter correctly for a URL. Figure out what's inside a Base64 string. Or take a **JWT** and see what its payload claims. For each of these there are one-liners, command-line tricks, or sketchy online converters — and with tokens, that last option is risky.

The [Coder](https://www.jpkc.com/tools/coder/) bundles these chores into **one** tool with seven tabs. You pick the right tab, paste your text, click **Encode** or **Decode** — done. Everything happens **right in your browser**: no account, no upload, no installation.

The tool is built for everyone who works with code and data: **developers** who translate between HTML, URLs, and Base64 all day; **backend and API people** who want to inspect a JWT without handing it to someone else's server; and anyone who needs to quickly embed an **image as a Data URI** in their CSS or HTML.

## The codecs at a glance

The interface is in English — the tabs are named exactly as shown here in parentheses. The seven functions group into three blocks:

**Markup and web**

- **HTML entities, basic** (*HTML* tab) — turns `&`, `<`, and `>` into HTML entities and back. The minimum needed to display a code snippet without the browser interpreting it as markup.
- **HTML entities, advanced** (*HTML+* tab) — same as above, plus double quote `"` (`&quot;`) and apostrophe `'` (`&#39;`). You need this when the text lands inside an attribute value.
- **URL encoding** (*URL* tab) — encodes a string for safe use in URLs (built on `encodeURIComponent`) and decodes it again.

**Binary and transport**

- **Base64** (*Base64* tab) — encodes text to Base64 and back, UTF-8 safe (including accents and emoji). Invalid Base64 input is detected and reported on decode.
- **Data URI** (*Data URI* tab) — converts **any file** into a Base64-encoded `data:` URI you can embed directly in CSS or HTML. With a progress indicator and file info.

**Data and tokens**

- **JSON string** (*JSON* tab) — escapes special characters such as `\n`, `\t`, `\"` to their JSON escape sequences (Escape) and reverses that (Unescape).
- **JWT decoder** (*JWT* tab) — splits a JSON Web Token into **header**, **payload**, and **signature**, and shows the header and payload as formatted JSON. Important: the tool **decodes and displays only** — it does **not** verify the signature and does **not** generate tokens. More on that in the manual.

## Everything runs in the browser

The Coder is a **pure client-side tool**. The server only delivers the page; the actual encoding and decoding is done by JavaScript locally in your browser. There is **no** server-side processing of your input.

That's not just fast — it's a real **privacy advantage**: a JWT you decode, a file you turn into a Data URI, a string you Base64-encode — none of it leaves your machine or gets sent to a server. Tokens in particular often carry sensitive claims; here they stay local.

## Try it now

**[→ Open the Coder](https://www.jpkc.com/tools/coder/)** — pick a tab, paste your text, click Encode or Decode. No account, free, right in the browser.

## Related JPKCom tools

When the Coder hits its limits, these tools take over:

- **[Convertor PRO](https://www.jpkc.com/db/en/tools/convertor/)** — converts between HTML/XML, Unicode, UTF-8, hexadecimal, YAML, JSON, and TOML. The bigger sibling for format conversions beyond the plain encode/decode tabs.
- **[JSON Editor](https://www.jpkc.com/db/en/tools/json/)** — format, validate, and transform JSON. Ideal for taking a decoded JWT payload or an unescaped JSON string further.
- **[Generator](https://www.jpkc.com/db/en/tools/generator/)** — generate passwords, BCrypt/Argon2 hashes, TOTP codes, and more — the security side next to the JWT tab.

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There's more on the subpages: the **[manual](https://www.jpkc.com/db/en/tools/coder/manual/)** with every tab in detail, hands-on **[examples](https://www.jpkc.com/db/en/tools/coder/examples/)**, and a collection of **[tips & tricks](https://www.jpkc.com/db/en/tools/coder/tips/)**.