Developer Tools
The small utilities that come up constantly during debugging — encoding, timestamps, hashes, colours and formatters — without a round trip to a server.
Encoding, hashing, time, colour, regex and formatting utilities that come up in everyday work.
24 tools
24 tools
- Base64 EncodeEncode text or files to Base64, with URL-safe and line-wrap options.TextBase64
- Base64 DecodeDecode Base64 back to text, with automatic URL-safe and padding handling.Base64Text
- URL EncodePercent-encode text for safe use in URLs, with component and full-URL modes.TextEncoded text
- URL DecodeDecode percent-encoded URLs and parameters back to readable text.Encoded textText
- HTML EncodeEscape HTML special characters so markup and code display as text.TextHTML entities
- HTML DecodeConvert HTML entities back into the characters they represent.HTML entitiesText
- JWT DecoderDecode JWT header and payload claims. Signature is not verified.JWTJSON
- UUID GeneratorGenerate cryptographically random UUID v4 identifiers in bulk.OptionsUUID
- Timestamp ConverterConvert between epoch timestamps, ISO 8601 and human-readable dates.TimestampDate
- Unix Time ConverterWork with Unix epoch time, including arithmetic and timezone comparison.Unix timeDate
- Regex TesterTest regular expressions live with match highlighting and capture groups.Pattern + textMatches
- Text DiffCompare two blocks of text line by line and see additions and removals.TextDiff
- Hash GeneratorCompute SHA-1, SHA-256, SHA-384, SHA-512 and CRC32 checksums.TextHash
- Color ConverterConvert colours between HEX, RGB, HSL and HSV with a contrast check.ColorColor
- SQL FormatterFormat SQL queries with keyword casing and dialect-aware indentation.SQLSQL
- HTML FormatterIndent and clean up HTML markup with configurable wrapping.HTMLHTML
- CSS FormatterBeautify CSS with consistent indentation, or compact it back down.CSSCSS
- JavaScript FormatterBeautify JavaScript and JSON-like code with configurable style options.JavaScriptJavaScript
- Markdown PreviewWrite Markdown and see the rendered HTML result side by side.MarkdownHTML
- Lorem Ipsum GeneratorGenerate placeholder paragraphs, sentences, words or list items.OptionsText
- XML FormatterRe-indent or minify XML, keeping comments and whitespace inside elements.XMLXML
- XML ValidatorCheck that XML is well-formed and get the line and column of the first error.XMLReport
- YAML FormatterNormalise YAML indentation across a whole stream while keeping every comment.YAMLYAML
- YAML ValidatorValidate a YAML stream, with duplicate keys treated as the error they are.YAMLReport
Encoding, and what each one is for
Base64, URL percent-encoding and HTML entities all make text safe to carry somewhere, but they solve different problems and are not interchangeable. Base64 turns arbitrary bytes into printable ASCII so binary can travel through a text-only channel. Percent-encoding escapes characters that have reserved meaning inside a URL. HTML entities stop markup characters from being parsed as markup.
None of them is encryption. Base64 in particular is trivially reversible, so it protects nothing — if you find a secret that is merely Base64-encoded, treat it as plaintext that has been exposed.
Why these run locally
The values developers paste into utilities like these are often exactly the values that should not leave the machine: a JWT from a staging environment, a token from a log, a hash of something sensitive. Every tool here runs in your browser, so those values are never transmitted. The JWT Decoder in particular only reads the token — it decodes the header and claims for inspection and deliberately does not verify the signature, which would require the signing key.
You can confirm this the same way you would audit any client-side claim: open the network panel and watch while you use a tool, or disconnect from the network after the page loads and keep working.
Timestamps and hashes
Timestamp conversion trips people up because the unit is rarely stated. A value around 1.7 billion is epoch seconds; the same moment in milliseconds is a thousand times larger. The converters show both alongside the ISO 8601 form and your local time so the ambiguity is visible rather than assumed. Hashes are computed with the browser’s native Web Crypto API, which means the same digests you would get from any standard implementation.