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.

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

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.