Developer tools

These tools cover the small jobs that come up in the middle of development work: an identifier for a new record, a value that has to be encoded before it goes into a URL, a hash to compare with a checksum, a throwaway password for a test account, a JSON response that is one long line and refuses to parse. They are written for developers, students learning how these formats work, and IT administrators who need a result quickly without installing anything. Each one runs in your browser, nothing you type is uploaded, and no account is needed.

What each tool does

The UUID generator makes version 4 (random) or version 7 (time-ordered) UUIDs, up to 100 at once, and has a checker that reads the version, the variant and, for version 7, the timestamp of any UUID you paste. Use version 7 when identifiers should sort by creation time and version 4 when they should reveal nothing.

The Base64 encoder and decoder works on text as UTF-8, so ş and emoji come out right where btoa() throws. It can write the URL-safe alphabet, drop or keep padding and wrap lines at 64 or 76 columns.

The URL encoder and decoder has three encoding types, component, whole URL and form data, which differ in what they leave alone and in how they write a space (%20 or +). It also shows the parts of an http or https address, and it never opens the address.

The password generator draws each character independently from the sets you choose and shows the exact entropy in bits. It gives no crack-time estimate because that depends on the attacker.

The hash generator computes MD5, SHA-1, SHA-256, SHA-384 and SHA-512 of a text at once, as hex or Base64.

The JSON formatter validates, indents or minifies JSON, can sort keys, and lists statistics about the document.

Which tool for which situation

• A new primary key, request ID or test fixture: UUID generator. Checking what kind of UUID a value is: its checker.
• A text with accented letters has to travel through a system that only accepts ASCII: Base64 encoder.
• A query value contains &, # or a space: URL encoder, component type.
• Your hash does not match the one in a release note: hash generator, then compare the byte count first.
• A password for a staging account or a service that you will store in a password manager: password generator.
• An API response that is a single line, or a config file that fails to load: JSON formatter.

Combining them

A value copied from a query string is sometimes percent-encoded Base64 holding JSON. Run it through the URL decoder with the component type, paste the result into the Base64 decoder, which accepts the URL-safe alphabet and a missing =, and paste the decoded text into the JSON formatter. Each step is a separate paste on your device. A mismatch between two hashes is another common case: the hash generator shows the input size in bytes, and a difference of one or two bytes against the other side usually means a trailing newline or Windows line endings.

Things to keep in mind

• Encoding is not protection. Base64 and percent-encoding are reversible by anyone. A token written in Base64 is still a token.
• Hashes are one-way, and fast ones are not for passwords. MD5 and SHA-1 have demonstrated collisions, so keep them for checksums and cache keys, not signatures or security checks. For stored passwords use a dedicated, slow, salted password hashing function, which this site does not provide.
• A UUID is an identifier, not a secret. A version 7 value also states when it was made, to the millisecond.
• These tools handle text. There is no file mode for hashing or Base64.
• JSON is stricter than JavaScript. Single quotes, comments and trailing commas are errors, and the formatter tells you exactly where.