DevKit

~/devkit 142 tools · 11 groups · runs in your browser

Free online developer tools that run in your browser

142 tools for converting, encoding, formatting and checking the data you work with every day: timestamps, JSON, Base64, hashes, regex, colors and more. Everything runs locally in your browser, so what you paste stays on your machine.

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01Time & Date 8

Unix TimestampSee the current epoch time, turn any Unix timestamp into a readable date, or turn a date in any time zone into a…Cron ParserPaste a crontab schedule to get a plain-English description, the next 10 run times, and a field-by-field breakdown.Cron GeneratorPick when the job should run and get the cron expression, its meaning in plain English, the next 5 run times and…Time Zone ConverterPick a date, a time and two time zones to convert between them, and compare the same moment across major cities.Date DifferenceFind the exact time between two dates — in calendar terms, total days and business days — or add and subtract a…ISO 8601 DurationDecode a duration like PT1H30M into its parts, total seconds and end date — or build one from numbers, seconds or two…Week NumberSee the current week number, convert any date to its ISO week (2026-W40) and back, and list every week of the year with…Age CalculatorEnter a date of birth to get the exact age today or on any date, the countdown to the next birthday, and milestones…

02Encode & Decode 16

Base64 Encode/DecodeConvert text or any file to Base64 and back.Image to Base64Drop an image to get its data URI, raw Base64, a CSS background rule and an tag — or paste a data URI to preview and…Base32 Encode/DecodeConvert text to Base32 and back with the standard RFC 4648 alphabet or the base32hex, Crockford and z-base-32 variants.Base58 Encode/DecodeConvert text or hex bytes to Base58 and back, with the Bitcoin, Ripple or Flickr alphabet.URL Encode/DecodePercent-encode text for use in a URL, or decode %XX sequences back to readable text.HTML EntitiesEscape special characters so text displays literally in HTML, or turn entities such as &, é and &#x1F680…XML Escape/UnescapeMake text safe to place inside XML elements and attributes, or convert <, &, ' and &#xNN; references back…Text to HexTurn any string into the hexadecimal values of its UTF-8 bytes, formatted the way your code or protocol expects.Hex to TextPaste hex bytes in almost any notation and get the UTF-8 text they represent.Text to BinarySee the exact bits behind any text: every UTF-8 byte written as eight binary digits.Binary to TextPaste binary digits and get the text they encode, with clear errors for stray characters or incomplete bytes.Unicode EscapeEscape non-ASCII characters for source code, JSON or HTML, or turn \u escapes and U+ code points back into readable…JWT DecoderPaste a JSON Web Token to read its header and claims, see when it was issued and when it expires, and verify its…JWT EncoderEdit the header and the payload as JSON, then sign with a secret (HS*) or a private key (RS*, PS*, ES*) to get a JSON…Certificate DecoderPaste a PEM certificate, a whole chain or the Base64 of a DER file to read who it was issued to, by whom and until…String EscapeTurn raw text into a correctly escaped string literal for your language, or unescape a literal back to plain text.

03Hash & Security 13

MD5 HashCompute the MD5 digest of any text or file, as lowercase hex, uppercase hex or Base64 — no upload needed.SHA-1 HashGenerate the 160-bit SHA-1 digest of text or a file, locally in your browser.SHA-256 HashCompute the SHA-256 digest of text or a file — the standard checksum for downloads, APIs and blockchains.SHA-512 HashCompute the 512-bit SHA-512 digest of any text or file without uploading it.Hash GeneratorGet every common digest of your text or file side by side: MD5, SHA-1, SHA-256, SHA-384 and SHA-512.HMAC GeneratorSign a message with a secret key using HMAC and get all four SHA variants at once — useful for testing webhook and API…Bcrypt GeneratorHash a password with bcrypt at a chosen cost, see how long it takes, and check whether a password matches an existing…Password GeneratorCreate strong random passwords or memorable passphrases in bulk, with the entropy of each shown in bits.UUID GeneratorCreate up to 1,000 UUIDs at once — random v4 or sortable v7 — and inspect any UUID to see its version, variant and…CRC32 CalculatorGet the CRC-32 of a text, a list of hex bytes or a file, together with CRC-32C, CRC-16/ARC, CRC-16/CCITT-FALSE, CRC-8…ULID GeneratorCreate up to 1,000 ULIDs at once, decode the timestamp inside any ULID and convert between the ULID and UUID forms of…Nano ID GeneratorCreate secure, URL-friendly Nano IDs of any length and alphabet, and check how safe that combination is against…RSA Key GeneratorCreate an RSA, ECDSA or Ed25519 key pair with the Web Crypto API and get it as PEM and JWK, with the SHA-256…

04Formatters & Minifiers 18

JSON FormatterPaste raw or minified JSON to pretty-print it with the indentation you want.JSON MinifyRemove indentation, line breaks and spaces from JSON to make it as small as possible.JSON ViewerPaste JSON to browse it as a collapsible tree.XML FormatterIndent XML so the element hierarchy is readable, and check that the document is well-formed.HTML FormatterReformat messy or minified HTML into clean, consistently indented markup.CSS FormatterTurn minified or inconsistent stylesheets into readable CSS with one declaration per line.JavaScript FormatterPaste JavaScript or JSX to format it with Prettier.TypeScript FormatterFormat TypeScript code with Prettier's TypeScript parser.SQL FormatterBeautify long SQL queries with clause-per-line layout and consistent keyword case.YAML FormatterNormalize indentation and spacing in YAML files such as Kubernetes manifests, CI workflows and Docker Compose files…GraphQL FormatterFormat GraphQL operations and schema definitions so nested selections are easy to read.Markdown FormatterNormalize Markdown syntax: consistent headings and list markers, aligned tables and optional line wrapping for prose.PHP FormatterFormat PHP source with the Prettier PHP plugin.CSS MinifierShrink stylesheets by removing comments and whitespace and shortening values.JavaScript MinifierCompress JavaScript with Terser, the minifier used by webpack, Vite and Rollup.HTML MinifierReduce HTML size by removing comments and redundant whitespace, without breaking <pre> blocks or inline spacing.XML MinifierCompact XML to a single line by removing whitespace between tags and, optionally, comments.JS ObfuscatorMake JavaScript harder to read and copy by renaming identifiers, moving strings into encoded arrays and restructuring…

05Linters & Validators 8

JSON ValidatorCheck whether a JSON document is valid.JSON Schema ValidatorPaste a JSON Schema and a JSON document side by side.Email ValidatorPaste one or many email addresses to check their syntax, catch typos and throw-away domains, and optionally confirm…YAML ValidatorCheck whether a YAML document parses.XML ValidatorCheck whether an XML document is well-formed.Dockerfile LinterPaste a Dockerfile to check it against more than 40 rules.GitHub Actions ValidatorPaste a workflow file from .github/workflows to check its structure.GitLab CI ValidatorPaste a .gitlab-ci.yml to check its structure without pushing and without a GitLab token.

06Data Conversion 21

CSV to JSONPaste CSV and get a JSON array with one object per row, keyed by the header.JSON to CSVTurn a JSON array of objects into CSV with one column per key.CSV to TSVChange a CSV file into tab-separated values that paste cleanly into spreadsheets, databases and command-line tools.TSV to CSVConvert tab-separated text, such as cells copied from a spreadsheet, into a properly quoted CSV file.CSV to XMLTurn each CSV row into an XML element whose children are named after the header columns.CSV to HTML TableGenerate semantic HTML table markup from CSV and preview the result before copying it.JSON to XMLConvert any JSON document into indented, well-formed XML with predictable rules for arrays and attributes.XML to JSONParse XML with the browser's own parser and get a clean JSON object that keeps attributes and repeated elements.JSON to YAMLConvert JSON into readable YAML with two-space indentation, ready for config files.YAML to JSONParse YAML, report syntax errors precisely, and output the equivalent JSON.JSON to HTML TableRender a JSON array as an HTML table to inspect API data, or copy the markup into a page or report.JSON to TSVConvert JSON records into tab-separated rows that paste directly into spreadsheet cells.XML to CSVExtract the repeated records from an XML document, such as items in a feed or rows in an export, into a CSV table.XML to HTML TableView the repeating records in an XML file as a table and copy the HTML markup.JSON to TypeScriptPaste a JSON sample, such as an API response, and get TypeScript interfaces for it, with nested types, optional fields…JSON to GoPaste a JSON sample and get Go struct types with json tags, named and formatted the way gofmt and golint expect.JSON to ZodPaste a JSON sample and get a Zod schema that validates it, with the inferred TypeScript type.JSON to JSON SchemaPaste a JSON document and get a JSON Schema that describes it: types, required keys, array items and string formats.TOML to JSONParse TOML, report syntax errors with their position, and output the equivalent JSON.JSON to TOMLTurn a JSON object into a TOML document with tables, arrays of tables and dates.SQL to JSONPaste INSERT statements or a database dump and get the rows as JSON, one object for each row.

07Number Conversion 12

Number Base ConverterType a number in any field — binary, octal, decimal, hex or a custom base — and every other field updates instantly.Binary to DecimalEnter a binary number to get its decimal value, with each bit's place value worked out below.Decimal to BinaryEnter a decimal (base-10) number to get its binary form, with the division-by-two working shown below.Hex to DecimalEnter a hexadecimal number to get its decimal value, with the powers-of-16 working shown step by step.Decimal to HexEnter a decimal number to get its hexadecimal form, with the repeated division by 16 worked out below.Binary to HexEnter a binary number to get its hexadecimal form, with the 4-bit grouping that makes the conversion work.Hex to BinaryEnter a hex value to see it as binary, with each hex digit expanded into its four bits.Octal to DecimalEnter an octal number to get its decimal value, with the powers-of-8 working shown step by step.Decimal to OctalEnter a decimal number to get its octal form, with the repeated division by 8 worked out below.Data Size ConverterConvert a file or disk size between decimal (SI) and binary (IEC) units, and see how long it takes to transfer at a…Unit ConverterPick a category and two units to convert between them, with a table of the same value in every other unit.Roman NumeralsTurn a number into Roman numerals or read a Roman numeral as a number; invalid numerals are explained, not just…

08Text 17

Word CounterPaste or type text to see live word, character, sentence and paragraph counts, estimated reading time and the most…Case ConverterType a phrase or identifier and get it in twelve cases at once, each with its own Copy button.Slug GeneratorConvert page titles into lowercase, hyphenated URL slugs, one per line, ready for a CMS, a static site or a database…Strip HTML TagsConvert HTML into readable plain text: tags removed, entities decoded, paragraphs and line breaks kept.Strip XML TagsExtract the text content from XML, RSS feeds, SVG or config files, without the markup.Text DiffPaste the original and the changed text to see exactly what was added and removed.JSON DiffPaste two JSON documents to see every value that was added, removed or changed, with its path.Regex TesterWrite a JavaScript regular expression, see every match highlighted as you type, inspect groups, and preview a…JSONPath TesterType a JSONPath expression and see the matching values of your JSON document, each with its normalized path.Remove Duplicate LinesPaste a list and remove repeated lines without changing the order of the rest.Sort LinesSort a list of lines A–Z, in natural order, by length, reverse it or shuffle it randomly.Lorem Ipsum GeneratorGenerate dummy text for mockups, layouts and tests: choose how many paragraphs, sentences or words, and copy.Markdown PreviewEdit Markdown on the left and see it rendered on the right, or switch to the HTML code to copy it.Regex Find & ReplaceReplace every match of a regular expression in a text, with capture groups in the replacement and a preview of what…Add Line NumbersPut a number in front of every line of a text or a code snippet, or remove the numbers from a listing you copied.Unicode Character InspectorPaste a text to see what it is really made of: every code point with its name and encodings, and the invisible or…ASCII Art GeneratorType a word or a few lines, pick a FIGlet font and get a text banner for a README, a CLI splash screen or the header of…

09Web 13

.htaccess GeneratorTick the rules you need and get a commented .htaccess for Apache 2.4 — HTTPS and www redirects, 301s, compression…Nginx Config GeneratorPick the kind of site and get a commented nginx config — HTTP to HTTPS and www redirects, SSL, reverse proxy with…Meta Tag GeneratorFill in your page details to get title, description, canonical, robots, Open Graph and Twitter tags, with length checks…Favicon GeneratorMake a favicon from one or two letters or your own image, then download favicon.ico, all PNG sizes, a web manifest and…QR Code GeneratorCreate a QR code for a link, Wi-Fi login, contact card or any text.URL ParserBreak any URL into its parts, decode percent-encoding, see the punycode form of international domains, and edit query…User Agent ParserPaste a User-Agent header to identify the browser, engine, OS, device type and crawlers.HTTP Status CodesEvery standard HTTP response status code with what it means, when to return it and the RFC that defines it.Chmod CalculatorConvert Unix permissions between checkboxes, octal numbers like 755 and symbolic strings like rwxr-xr-x, including…HTML/CSS/JS PlaygroundA lightweight online code editor: type HTML, CSS and JavaScript, watch the preview update, and read console output and…SVG OptimizerPaste or drop an SVG exported from Inkscape, Illustrator or Figma and get a smaller file: SVGO removes editor data…Robots.txt GeneratorBuild a robots.txt from Allow and Disallow lists for all robots or for specific crawlers, block AI bots in one click…XML Sitemap GeneratorPaste URLs one per line — optionally with lastmod, changefreq and priority — and get a valid XML sitemap, sitemap index…

10CSS 9

Color ConverterPaste any CSS color or pick one to get every common notation, a WCAG contrast check against white, black and a second…HTML Color CodesEvery named color CSS supports, grouped by family with HEX and RGB values.CSS Gradient GeneratorBuild a linear, radial or conic gradient visually: add, move and recolor stops, set the angle or position, and copy…Box Shadow GeneratorStack several shadow layers, tune offset, blur, spread, color and opacity, and see the result on a live card before…PX to REM ConverterType a length to see it in px, rem, em, pt and %, or paste CSS to convert all px values to rem at once while 1px…Contrast CheckerEnter a foreground and a background color to get the WCAG contrast ratio, pass or fail for AA and AAA, a live preview…Border Radius GeneratorRound each corner on its own or link them, switch to the 8-value elliptical syntax for blob shapes, and copy the…Flexbox GeneratorChange the container and item properties of a flex layout, watch the numbered items move in the live preview and copy…CSS Grid GeneratorSet the tracks of a grid, draw the areas of your layout directly on the preview and copy the CSS with…

11Network 7

CIDR CalculatorEnter an address with a prefix length, netmask or wildcard mask to get the network, broadcast and usable host range…IP to IntegerType an IPv4 or IPv6 address, or a number in decimal, hexadecimal, octal or binary: the kind is detected and every…MAC Address LookupPaste one or many MAC addresses in any notation — or the output of arp -a or ip neigh — to see the vendor, the assigned…What Is My IPShows the public IPv4 and IPv6 address your connection uses on the internet, and what your browser reports about itself.DNS LookupQuery A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, SRV or PTR records for a domain or IP address and see the answer with its…cURL to FetchPaste a curl command — for example from the browser's developer tools, “Copy as cURL” — and get the equivalent fetch()…cURL to AxiosPaste a curl command and get the equivalent axios call — axios.get(), axios.post() and friends with a config object —…