Developer tools
The tools a developer reaches for mid-task: decode what an API really returned, check a hash, make an unreadable payload readable, or look up a status code without leaving the browser. Each one takes what you paste and answers immediately, without a round trip to a service you would then have to trust.
Base64 Encoder / DecoderEncode and decode Base64 online — free.JWT decoderDecode a JWT, read its claims and dates, and check its HMAC signature.URL encoder / decoderEncode and decode URLs and query parameters.Hex to text converterDecode a hexadecimal string back into readable text (ignores spaces and 0x prefixes).HTML Entity Encoder / DecoderConvert text to HTML entities and back, escaping <, >, &, quotes and optionally all non-ASCII characters.JSON String Escape / UnescapeTurn raw text into a JSON-safe string and back, with control characters, \uXXXX, emoji surrogate pairs and lone surrogates handled exactly like JSON.stringify.
JSON formatterFormat, beautify or minify JSON — with instant validation.Markdown to HTMLSee your Markdown rendered live and copy the clean HTML behind it.CSS BeautifierReformat minified or messy CSS into clean, properly indented rules — or minify it back.CSS minifierShrink CSS by removing comments and unnecessary whitespace.CSV to JSON converterParse CSV text (with header row) into a JSON array of objects, handling quoted fields. Drop a file in rather than pasting it — it is read in your browser and never uploaded.CSV to Markdown tableTurn CSV into a Markdown table, quoting and all: a field may hold the delimiter, a line break or a pipe and the table still lines up. Comma, semicolon (French Excel), tab or pipe, detected or forced.
Hash generatorCompute 15 hashes (MD5, SHA-256, SHA-3, CRC-32…) of a text or a file.UUID generatorGenerate UUID v7, v4, v5, v3, v1 or v6 in bulk, in several output formats.Adler32 Checksum CalculatorGenerate a Adler-32 hash of any text instantly in your browser, with hex or Base64 output. Used in zlib and PNG.Atbash cipherEncode or decode text with the Atbash substitution cipher (A↔Z, B↔Y…). Paste the text or drop the file; nothing leaves the page either way.Caesar cipher (ROT13)Encode or decode text with a Caesar shift cipher — ROT13 by default.CRC32 Checksum CalculatorGenerate a CRC32 hash of any text instantly in your browser, with hex or Base64 output. Fast integrity check (zip, PNG).
Number base converterConvert numbers between all 35 bases, exactly, with two's complement.Regex testerTest a regular expression and see what it does: matches highlighted in the text, every capture group listed, a replace panel, and the pattern read back to you piece by piece. Flags are toggles that say what they change, and a pattern that could freeze the page is flagged before you run it.ASCII code converterConvert text to ASCII/Unicode code points and back.Programming case converterConvert identifiers between camelCase, snake_case, kebab-case, PascalCase and CONSTANT_CASE, one per line. Runs of capitals split correctly: parseHTTPResponse becomes parse_http_response.Column extractorExtract a single column from delimited data (CSV, TSV…). Works on a pasted block or on a file you drop in.Delimiter converterSwap the delimiter of your data — comma, tab, semicolon, pipe or space. Drop a file in rather than pasting it — it is read in your browser and never uploaded.
Color converterConvert a colour to HEX, RGB, HSL, HSV, CMYK, LAB and OKLCH, with contrast.Color Contrast CheckerWCAG contrast ratio between text and background, with AA/AAA pass-fail and a live preview.Color InverterInvert a colour (255 − RGB) or take its complement, in HEX/RGB/HSL/CMYK with the contrast between them.Color Scheme GeneratorDerive complementary, analogous, triadic, tetradic, split and monochromatic schemes from a base colour.CSS CompressorMinify CSS by stripping comments and whitespace to shrink your stylesheet's size.CSS Flexbox PlaygroundExperiment with flex-direction, wrap, justify-content, align-items and gap — live preview and copyable CSS.
Barcode generatorGenerate an EAN, UPC, CODE128 or CODE39 barcode and download it as SVG or PNG.CSV / JSON / YAML converterConvert between CSV, TSV, JSON and YAML, and see the rows as a table.Fake data generatorGenerate mock people as JSON, NDJSON, CSV or SQL — columns and countries of your choosing.QR Code GeneratorCreate a QR code from any text or URL — free.ASCII Table ReferenceFull ASCII table (0-127) with a decimal / hex / octal / binary / character converter and a text-to-codes panel.Aspect ratio calculatorFind the aspect ratio of any width and height, like 16:9.