What is Base64 decoding?

Base64 decoding is the process of translating a Base64-encoded ASCII string back into its original binary representation or readable text format. It takes groups of four 6-bit characters and reconstructs the original 8-bit bytes.

How do I decode Base64 to readable text?

Paste your Base64 string into the input box. The tool automatically processes the string in real time, converting encoded characters into UTF-8 text or binary content.

Can I decode Base64 online for free?

Yes. This online Base64 decoder runs directly inside any modern web browser without requiring software installations, subscriptions, or account creation.

Is my data uploaded to an external server?

No. All encoding and decoding operations execute strictly client-side within your browser using JavaScript Web APIs. Your input strings and converted files are never transmitted to any external server or stored anywhere.

What is the difference between Base64 and Base64URL?

Standard Base64 uses '+' and '/' characters with optional '=' padding, which can conflict with URL query strings. Base64URL replaces '+' with '-' and '/' with '_', and omits trailing '=' padding for safe web tokens and JWTs.

What is the difference between encodeURI and encodeURIComponent?

encodeURI is intended for complete URLs and preserves structural delimiters such as ://, /, ?, #, and &. encodeURIComponent is designed for individual query parameter values and path components, converting all delimiters (like &, =, ?, and /) into percent codes so they do not break the URL structure.

Why are spaces encoded as %20 or +?

In standard RFC 3986 percent-encoding for URLs, a space is encoded as %20. However, in HTML form submissions (application/x-www-form-urlencoded), query string spaces are traditionally replaced by the plus sign (+). Both formats are widely recognized, and this tool supports toggling between them.

Does this tool support international Unicode characters and emojis?

Yes. The tool converts multi-byte UTF-8 Unicode characters (such as German umlauts ä, ö, ü, ß, Chinese, Japanese, Cyrillic, and emojis like 🚀) into valid sequences of percent-encoded UTF-8 bytes (e.g., ä becomes %C3%A4).

Are my entered URLs or text data sent to an external server?

No. All URL encoding and decoding operations execute 100% locally inside your web browser using standard Web APIs. No text, tokens, or queries are ever sent over the network or saved on any server.

How does the tool handle invalid or malformed percent sequences?

If you attempt to decode an incomplete or corrupt percent sequence (such as %ZZ or a dangling %), the tool catches the error gracefully, points out the exact character position of the malformed token, and prevents application crashes.

What is the difference between encodeURI and encodeURIComponent?

encodeURI is intended for complete URLs and preserves structural delimiters such as ://, /, ?, #, and &. encodeURIComponent is designed for individual query parameter values and path components, converting all delimiters (like &, =, ?, and /) into percent codes so they do not break the URL structure.

Why are spaces encoded as %20 or +?

In standard RFC 3986 percent-encoding for URLs, a space is encoded as %20. However, in HTML form submissions (application/x-www-form-urlencoded), query string spaces are traditionally replaced by the plus sign (+). Both formats are widely recognized, and this tool supports toggling between them.

Does this tool support international Unicode characters and emojis?

Yes. The tool converts multi-byte UTF-8 Unicode characters (such as German umlauts ä, ö, ü, ß, Chinese, Japanese, Cyrillic, and emojis like 🚀) into valid sequences of percent-encoded UTF-8 bytes (e.g., ä becomes %C3%A4).

Are my entered URLs or text data sent to an external server?

No. All URL encoding and decoding operations execute 100% locally inside your web browser using standard Web APIs. No text, tokens, or queries are ever sent over the network or saved on any server.

How does the tool handle invalid or malformed percent sequences?

If you attempt to decode an incomplete or corrupt percent sequence (such as %ZZ or a dangling %), the tool catches the error gracefully, points out the exact character position of the malformed token, and prevents application crashes.

Your Base64 data stays in your browser. Client-side only

URL Encoder & Decoder

Fast, client-side URL percent-encoding and decoding. Encode special characters, query parameters, and Unicode strings securely in your browser.

Quick Samples:

Language:ENDE

Encode Mode:

Encode space as "+"Decode "+" as space

Input (Plain or Encoded URL / Text)

71 chars71 B

100% Client-Side in Browser

Result Output

0 chars0 B

What Is URL Encoding (Percent-Encoding)?

URL encoding, officially specified as percent-encoding in the RFC 3986 Uniform Resource Identifier (URI) specification, is a mechanism for converting characters into a safe format that can be reliably transmitted over the internet across any web server, browser, or proxy.

The standard URI character set is restricted to a small subset of US-ASCII characters: unreserved letters (A–Z, a–z), numbers (0–9), and four symbols (-, _, ., ~). Any other characters—such as spaces, punctuation, quotes, German umlauts (ä, ö, ü, ß), and emojis—must be converted into a percent sign (%) followed by two hexadecimal digits representing their UTF-8 byte values.

Example: A space character becomes %20. An ampersand (&) becomes %26. A German "ä" becomes %C3%A4.

What Is URL Decoding?

URL decoding is the reverse process of percent-encoding. It parses hexadecimal triplets (e.g., %2F) and restores the original characters (e.g., /) or multi-byte UTF-8 Unicode characters.

When web servers or APIs receive HTTP GET query parameters, they automatically decode the percent-encoded strings so that application code reads natural text (for instance, reading a search query "developer tools" rather than "developer%20tools").

Common URL Encoded Characters Reference Table

A quick-reference lookup for common reserved characters and their RFC 3986 percent-encoded hexadecimal values:

Character	Name	Percent Code	Purpose / Delimiter
<space>	Space	%20 (or +)	Separates words in query values
!	Exclamation mark	%21	Reserved sub-delimiter in RFC 3986
"	Double quote	%22	Delimiter in JSON and HTML attributes
#	Number sign / Hash	%23	Fragment identifier anchor delimiter
$	Dollar sign	%24	Reserved sub-delimiter in URLs
%	Percent sign	%25	Escape character for percent-encoding
&	Ampersand	%26	Separates query string key-value pairs
'	Single quote	%27	Reserved sub-delimiter in RFC 3986
(	Open parenthesis	%28	Reserved sub-delimiter in RFC 3986
)	Close parenthesis	%29	Reserved sub-delimiter in RFC 3986
+	Plus sign	%2B	Represents space in form-encoded queries
,	Comma	%2C	Reserved sub-delimiter for lists in parameters
/	Forward slash	%2F	Path segment separator
:	Colon	%3A	Scheme/port separator
;	Semicolon	%3B	Sub-delimiter in path segments
<	Less than	%3C	Unsafe character in HTML contexts

The Difference: encodeURI vs. encodeURIComponent

encodeURI (Full URL Mode)

Designed to encode an entire complete URL. It assumes the string already has URL structure and preserves protocol delimiters, host slashes, query initiators (://, /, ?, &, #, =).

encodeURI("https://site.com/search?q=a&b=1")
➔ "https://site.com/search?q=a&b=1"

encodeURIComponent (Component Mode)

Designed for single query parameter values or path segments. It encodes all reserved characters including /, ?, &, and = so they do not conflict with the outer URL structure.

encodeURIComponent("https://site.com/search?q=a&b=1")
➔ "https%3A%2F%2Fsite.com%2Fsearch%3Fq%3Da%26b%3D1"

Practical Use Cases for URL Encoding

Query Parameters in Web APIs

When passing complex strings, email addresses, or search terms into GET parameters (e.g. user=john@doe.com becomes user=john%40doe.com).

OAuth & OpenID Redirect URIs

Authentication flows require passing the redirect callback URL as a parameter (e.g. redirect_uri=https%3A%2F%2Fmyapp.com%2Fcallback) so security gateways do not truncate parameters.

International URLs (IDN & Unicode)

Encoding non-ASCII characters like German umlauts (ä, ö, ü, ß), French accents, Cyrillic, and emojis ensures universal link compatibility across legacy routers and firewalls.

Frequently Asked Questions

Clear, concise answers to common questions about Base64 decoding, encoding, and specifications.

URL encoding (also known as percent-encoding) converts reserved and unsafe characters into a standard format recognized by RFC 3986. Because URLs can only contain a limited set of ASCII characters, characters like spaces, ampersands, question marks, and non-ASCII Unicode glyphs must be represented with a percent sign followed by two hexadecimal digits (e.g., %20 for space).

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