What's the difference between encodeURI and encodeURIComponent?

encodeURI is for encoding a complete URL — it preserves reserved URL characters (/, ?, &, =, #) so the URL structure stays intact. encodeURIComponent is for encoding a single component (like a query value) — it encodes those reserved characters too, so they're treated as data, not as URL syntax.

What characters are left unencoded?

Per RFC 3986, the unreserved characters are A-Z, a-z, 0-9, and the four marks: hyphen, underscore, period, tilde. Everything else is encoded as percent-encoded bytes. The four characters - _ . ! ~ * ' ( ) are kept by encodeURIComponent specifically.

Does it encode the entire URL or just a value?

Both — pick the mode that matches your case. For encoding the whole URL (rare), use URI mode. For encoding a single query parameter value (the common case), use component mode.

What happens if the input is already encoded?

If you encode it again, you get double-encoding (e.g., %20 becomes %2520). If you decode an already-decoded string, you get the same string back. The tool warns when it detects a double-encoded pattern in the input.

How do I encode a URL for use in a JSON value or HTML attribute?

Use URL encoding first (this tool), then JSON-escape or HTML-escape the result if the context requires it. URL encoding alone doesn't make a value safe inside JSON strings or HTML attributes — see our HTML Escape tool for the next layer.

Is my text sent to a server?

No. Encoding and decoding happen entirely in your browser using built-in JavaScript URL APIs. Your text never leaves your device — no upload, no logging.

Does it support international (Unicode) characters?

Yes. Unicode characters are encoded as their UTF-8 byte sequence, each byte as %XX. For example, the character é becomes %C3%A9. Decoding reverses this back to the original character.

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URL 编解码

对 URL 文本做编码和解码。

数据留在您的设备无需上传至服务器可离线使用

编码模式

输入模式

输入

编码输出

a%20b%2Bc

解码输出

a b+c

可直接拼接参数

a%20b%2Bc

状态

Ready

为什么用这个工具

快速处理 percent-encoding 和可读文本之间的转换。

适合调试参数、拼接链接和处理查询值。

输入结果即时同步。

如何使用

01输入原始文本或已编码文本。

02复制编码后或解码后的值。

复制前快速检查

先确认输入格式符合你的预期。

在把结果用于文档、链接、配置或消息前快速扫一眼。

只复制你真正需要的输出。

常见问题

如果编码字符串不合法呢？

解码结果会显示为空值。

URL 编解码

为什么用这个工具

如何使用

复制前快速检查

常见问题

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