Free Online Developer Tools

Format JSON, encode Base64, test regular expressions, generate UUIDs and more. Free, fast, and nothing is sent to a server.

JSON FormatterFormat, validate and minify JSON with clear error locations.
JSON to CSVTurn a JSON array into a CSV for Excel or Google Sheets.
CSV to JSONConvert CSV or spreadsheet exports into JSON.
JSON to YAMLConvert JSON to YAML and YAML to JSON.
Base64 Encode and DecodeEncode text to Base64 or decode Base64 back to text or a file.
URL Encode and DecodePercent-encode text for URLs or decode %20-style text.
Hash GeneratorMD5, SHA-1, SHA-256, SHA-512 and HMAC for text or files.
UUID GeneratorGenerate random v4 or time-ordered v7 UUIDs in bulk.
Password GeneratorCreate strong random passwords with the characters you choose.
JWT DecoderDecode JSON Web Tokens and check HMAC signatures.
Timestamp ConverterConvert Unix timestamps to dates and dates to timestamps.
Regex TesterTest regular expressions with highlighted matches and groups.
JSON ValidatorCheck that JSON is valid and see exactly where it isn't.
JSON MinifierRemove all the whitespace from JSON to make it as small as possible.
JSON ViewerExplore JSON as a collapsible tree, find keys and copy paths.
JSON DiffCompare two JSON documents and list every added, removed and changed value.
YAML to JSONConvert YAML to JSON, with clear errors for invalid YAML.
XML to JSONConvert XML to JSON, with attributes, repeated elements and text handled.
JSON to XMLConvert JSON to well-formed, indented XML.
JSON to TypeScriptGenerate TypeScript interfaces from example JSON.
JSON to ZodGenerate Zod schemas, and their TypeScript types, from example JSON.
JSON to GoGenerate Go structs with JSON tags from example JSON.
JSON to RustGenerate Rust structs with serde attributes from example JSON.
JSON to PythonGenerate Python dataclasses or Pydantic models from example JSON.
JSON to JSON SchemaGenerate a JSON Schema from an example JSON document.
HTML FormatterBeautify messy or minified HTML with clean indentation.
CSS FormatterBeautify minified CSS into readable, indented rules.
JavaScript FormatterBeautify minified or messy JavaScript with consistent indentation.
SQL FormatterFormat SQL queries for MySQL, PostgreSQL, SQL Server and more.
XML FormatterFormat, validate or minify XML, with clear error locations.
HTML MinifierShrink HTML by removing comments and spacing, safely.
CSS MinifierMinify CSS and merge duplicate rules to make stylesheets smaller.
JavaScript MinifierMinify JavaScript with Terser: shorter names, less code, same behavior.
Image to Base64Turn an image into a Base64 data URL for HTML, CSS or JSON.
Base64 to ImagePreview and download the image inside a Base64 string or data URL.
URL ParserSplit a URL into scheme, host, port, path, query parameters and fragment.
HTML Entity EncoderEncode text for HTML (< & ") or decode entities back to text.
Unicode EscapeTurn characters into \u escapes for JavaScript, Python, CSS or HTML, and back.
JSON EscapeEscape text to put inside a JSON string, or unescape it back.
Base32 Encode / DecodeEncode text to Base32 (RFC 4648) or decode Base32 back to text.
Morse Code TranslatorTranslate text to Morse code and back, and hear it played.
Text to BinaryConvert text to binary (UTF-8 bytes) and binary back to text.
Text to HexConvert text to hexadecimal bytes and hex back to text.
Text to ASCII CodesConvert text to ASCII (and Unicode) codes, and codes back to text.
Number Base ConverterConvert numbers between binary, octal, decimal, hex and any base to 36.
Binary to DecimalConvert binary numbers to decimal, and decimal to binary.
Decimal to BinaryConvert decimal numbers to binary, and binary to decimal.
Hex to DecimalConvert hexadecimal numbers to decimal, and decimal to hex.
Decimal to HexConvert decimal numbers to hexadecimal, and hex to decimal.
Markdown to HTMLConvert Markdown to clean HTML and preview it.
HTML to MarkdownConvert HTML to clean Markdown, tables included.
CSV ViewerView a CSV file as a table you can sort and filter.
CSV to SQLTurn CSV into CREATE TABLE and INSERT statements.
MD5 GeneratorGet the MD5 hash of text or a file.
SHA-1 GeneratorGet the SHA-1 hash of text or a file.
SHA-256 GeneratorGet the SHA-256 hash of text or a file.
SHA-512 GeneratorGet the SHA-512 hash of text or a file.
HMAC GeneratorCreate HMAC-SHA256 (and SHA-1, 384, 512) signatures with a secret key.
File ChecksumCheck a download's MD5 or SHA-256 checksum against the expected one.
Bcrypt GeneratorHash passwords with bcrypt and check a password against a hash.
ULID GeneratorGenerate sortable, URL-safe ULIDs that start with their creation time.
Nano ID GeneratorGenerate short, URL-safe random IDs with your own length and alphabet.
Random String GeneratorGenerate random strings, tokens and keys from any set of characters.
Passphrase GeneratorGenerate strong, memorable passphrases from random words.
Mock Data GeneratorGenerate fake names, emails, addresses and more as JSON, CSV or SQL.
TOTP GeneratorShow two-factor (TOTP) codes for a secret, like an authenticator app.
JWT EncoderCreate and sign JSON Web Tokens with HS256, HS384 or HS512.
Cron Expression ParserExplain a cron schedule in plain English and list its next run times.
Chmod CalculatorConvert Linux file permissions between checkboxes, 755 and rwxr-xr-x.
Subnet CalculatorCalculate network, broadcast, host range and mask for IPv4 and IPv6 CIDRs.
User Agent ParserSee the browser, OS and device behind a user agent string.
HTTP Status CodesLook up what any HTTP status code means, from 100 to 511.
MIME Type LookupFind the MIME type for a file extension, or the extensions for a type.
cURL to CodeConvert a curl command to JavaScript fetch, axios or Python requests.
.gitignore GeneratorBuild a .gitignore for your languages, frameworks, editors and OS.
Keycode FinderPress any key to see its event.key, event.code and keyCode.