NextTool
6 tools · runs in your browser

Web Tools

Encoders, decoders and inspectors for the plumbing between a browser and a server.

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All Web Tools

Grouped by what you want to get done. Star a tool to find it again on the homepage.

URLs and browsers · Break down URLs, user agents and file types.

3

URL Parser

Parse any URL into its components: protocol, host, path, query, fragment

User Agent Parser

Parse any user-agent string into browser, OS, device and engine details

Characters and encoding · HTML entities, Unicode code points and ASCII.

3

Unicode Converter

Convert characters to Unicode code points and back, supports emoji and scripts

ASCII Converter

Convert text to ASCII codes and ASCII codes back to characters

Related tools

Often used alongside these, from other categories.

About these Web Tools

Most of what breaks between a form and a server is an encoding question: a character that meant one thing in a URL and another in a query string, a MIME type that does not match the bytes, a string that was encoded twice. These tools do the small, exact transformations that make those problems visible, and they do them in the tab, which matters because the URLs people debug tend to carry tokens.

Choosing between these Web Tools

Encode for the position, not for the string

The same character needs different escaping in a path segment, a query parameter value and a form body. Encoding a whole URL at once is the classic mistake: it escapes the separators that make it a URL. Encode the component, then assemble.

Double encoding is the most common bug here

A value that arrives already encoded and is encoded again produces %2520 where %20 was meant. If a decoded string still contains percent signs followed by hex digits, it was encoded more than once, and the fix is upstream rather than another decode.

MIME type is a claim, not a fact

The type a server declares and the bytes it sends can disagree, and browsers increasingly refuse to guess. Checking a file's actual signature against its declared type is usually the fastest way to explain a download that opens as gibberish.

Questions people ask

Why does my URL break after encoding it?
Almost always because the whole URL was encoded rather than one component of it. The colon after the scheme, the slashes in the path and the ampersands between parameters are structural: escaping them turns a URL into a single opaque string.
Is Base64 a way to hide data?
No. Base64 is an encoding that makes binary data safe to put in text, and reversing it requires nothing but the decoder. Anyone who can see the encoded value can read the original. It provides no confidentiality whatsoever.
Do these tools send anything to a server?
No. Encoding, decoding and type detection are all local string and byte operations. The values people paste into web encoders are disproportionately signed URLs and API responses, which is a good reason for the tool not to be somebody else's server.

Guides on this topic

What a user agent string actually says about youEvery browser claims to be Mozilla. The string is part identification, part historical fiction, and it is a weaker signal every year.QR codes: what is actually encoded, and how to make one that scansThere is no database behind a QR code. Everything it knows is printed in the squares, which is why a long URL makes a code nobody can scan.URL encoding, HTML entities and MIME types: three things people mix upThe same ampersand needs three different treatments depending on where it is going. Getting them confused is how & ends up on a page.HTTP status codes: the handful that decide what search engines doMoving a page with the wrong redirect code throws away everything that page had earned. The difference is one digit.