Should I use %20 or + for a space?

%20 is the correct percent-encoding for a space and works everywhere, including in the path. + is a convention specific to the application/x-www-form-urlencoded format used by HTML forms and query strings, where it means "space" and a literal plus sign must itself be encoded as %2B. Outside a form-encoded query string, a + is just a literal plus character.

What is double encoding and how do I spot it?

Double encoding happens when a value that is already percent-encoded gets encoded again, turning %20 into %2520. It usually comes from encoding a value twice in code, or from a proxy or framework re-encoding a URL it received already encoded. This tool decodes your input and checks whether the result still contains valid percent-encoded sequences — if it does, it shows a banner so you can decode again.

Which characters actually need to be URL encoded?

Unreserved characters — letters, digits, and - _ . ~ — never need encoding. Reserved characters like : / ? # [ ] @ ! $ & ' ( ) * + , ; = have structural meaning in a URL and must be encoded when they appear as literal data rather than as a delimiter. Everything else, including spaces, non-ASCII letters and emoji, must always be percent-encoded.

Is my URL sent anywhere?

No. All encoding, decoding and parsing happens in your browser using the built-in URL and URLSearchParams APIs. Nothing you type is uploaded or stored — the tool doesn't even keep it in local storage, only your chosen mode and toggle settings persist.

Tools

URL Encoder / Decoder with Live Query String Parser

Encode, decode and parse URLs live, with a query string editor and double-encoding detection.

Encode and decode URLs with live synced panes, an editable query string table, double-encoding detection and a URL parser. Everything runs in your browser. Nothing is uploaded.

Decode + as space

encodeURIComponent — for a single value like a query param. Escapes : / ? # & = too.

Decoded

Encoded

Copy as code

Encode (decoded → encoded)

Decode (encoded → decoded)

About URL Encoder / Decoder

URL encoding trips people up constantly: encodeURI and encodeURIComponent behave differently, a space can be %20 or +, and encoding something twice silently breaks it. This tool keeps a decoded and encoded pane in sync, reports exactly where malformed percent-encoding breaks, detects double encoding, and gives you an editable query string table that rebuilds the URL live. It also generates equivalent code for JavaScript, Python, Go, Java, C#, PHP, Ruby and Rust.

Features

Synced decode / encode panes

Type in either pane and the other updates live, without fighting your cursor.

Precise decode errors

A malformed sequence like %zz or a truncated multi-byte character points to the exact index instead of just failing.

Double-encoding detection

Spots a value that has been percent-encoded more than once and offers to decode it back down, layer by layer.

URL parser & query table

Break a URL into protocol, host, port and path, and edit its query string as an ordered, duplicate-preserving table.

Query to JSON, and back

Convert a query string to JSON, with optional bracket notation for nested keys like user[name].

Copy as code

Generate the equivalent encode/decode call in JavaScript, Python, Go, Java, C#, PHP, Ruby and Rust.

How to use URL Encoder / Decoder

1
Pick an encoding mode
Choose Component, Full URL, Form or RFC 3986 depending on what you're encoding.
2
Type or paste your text
Type into either the decoded or encoded pane — the other one updates as you type.
3
Check for errors
A malformed percent-encoded sequence or double-encoded value shows a banner pointing to the exact problem.
4
Edit the query string
If your input has a query string, edit it as a table, remove tracking parameters, or convert it to JSON.
5
Copy the result or the code
Copy the encoded or decoded text, or copy an equivalent snippet in JavaScript, Python, Go and five other languages.

Use cases

Debugging a URL that fails to decode correctly in an API request
Stripping UTM and click-id parameters before sharing a link
Turning a query string into JSON for a config file or test fixture
Checking whether a URL has been encoded more than once
Generating the equivalent encode/decode call for a backend language

Privacy

Encoding, decoding and parsing all run in your browser using the built-in URL and URLSearchParams APIs. Nothing you type is uploaded — only your chosen mode and toggle settings are saved locally.

Frequently asked questions

encodeURI is meant for encoding a whole URL, so it leaves characters that are structurally meaningful in a URL — like :, /, ?, # and & — untouched. encodeURIComponent is meant for encoding a single piece, like a query parameter value, so it escapes those characters too. Using encodeURI on a query value can leave & or = unescaped and break the URL; using encodeURIComponent on a full URL will mangle the :// and path separators.

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Free online tool to encode and decode Base64. Supports text, files, and images. URL-safe encoding option. No signup required, 100% private - all processing happens in your browser.

JWT Decoder

Decode JWT tokens free online. View header, payload, and signature. Check expiration timestamps. Perfect for debugging authentication issues.

JSON Formatter

Free online tool to format, beautify, and validate JSON. Features include syntax highlighting, minification, error detection, and customizable indentation. No signup required, 100% private - all processing happens in your browser.

Developed by MadMVP

Book a call to build your vision into reality

About URL Encoder / Decoder

Features

Synced decode / encode panes

Type in either pane and the other updates live, without fighting your cursor.

Precise decode errors

A malformed sequence like %zz or a truncated multi-byte character points to the exact index instead of just failing.

Double-encoding detection

Spots a value that has been percent-encoded more than once and offers to decode it back down, layer by layer.

URL parser & query table

Break a URL into protocol, host, port and path, and edit its query string as an ordered, duplicate-preserving table.

Query to JSON, and back

Convert a query string to JSON, with optional bracket notation for nested keys like user[name].

Copy as code

Generate the equivalent encode/decode call in JavaScript, Python, Go, Java, C#, PHP, Ruby and Rust.

How to use URL Encoder / Decoder

Pick an encoding mode

Choose Component, Full URL, Form or RFC 3986 depending on what you're encoding.

Type or paste your text

Type into either the decoded or encoded pane — the other one updates as you type.

Check for errors

A malformed percent-encoded sequence or double-encoded value shows a banner pointing to the exact problem.

Edit the query string

If your input has a query string, edit it as a table, remove tracking parameters, or convert it to JSON.

Copy the result or the code

Copy the encoded or decoded text, or copy an equivalent snippet in JavaScript, Python, Go and five other languages.

Use cases

Debugging a URL that fails to decode correctly in an API request

Stripping UTM and click-id parameters before sharing a link

Turning a query string into JSON for a config file or test fixture

Checking whether a URL has been encoded more than once

Generating the equivalent encode/decode call for a backend language

Frequently asked questions

URL Encoder / Decoder with Live Query String Parser

Copy as code

About URL Encoder / Decoder

Features

Synced decode / encode panes

Precise decode errors

Double-encoding detection

URL parser & query table

Query to JSON, and back

Copy as code

How to use URL Encoder / Decoder

Pick an encoding mode

Type or paste your text

Check for errors

Edit the query string

Copy the result or the code

Use cases

Privacy

Frequently asked questions

What is the difference between encodeURI and encodeURIComponent?

Should I use %20 or + for a space?

What is double encoding and how do I spot it?

Which characters actually need to be URL encoded?

Is my URL sent anywhere?

Related tools

Base64 Encoder & Decoder

JWT Decoder

JSON Formatter

URL Encoder / Decoder with Live Query String Parser

Copy as code

About URL Encoder / Decoder

Features

Synced decode / encode panes

Precise decode errors

Double-encoding detection

URL parser & query table

Query to JSON, and back

Copy as code

How to use URL Encoder / Decoder

Pick an encoding mode

Type or paste your text

Check for errors

Edit the query string

Copy the result or the code

Use cases

Privacy

Frequently asked questions

What is the difference between encodeURI and encodeURIComponent?

Should I use %20 or + for a space?

What is double encoding and how do I spot it?

Which characters actually need to be URL encoded?

Is my URL sent anywhere?

Related tools

Base64 Encoder & Decoder

JWT Decoder

JSON Formatter