💻 Developer Tools

Everyday coding utilities: JSON, diff, cron, regex and more 115 free online tools, no sign-up.

• Code DiffCompare two snippets of text or code line by line
• UUID & Password GeneratorGenerate UUIDs and strong random passwords
• JSON DiffCompare two JSON documents and highlight differences
• JSON ValidatorValidate JSON syntax with precise error messages
• JSON Schema GeneratorInfer and generate a JSON Schema from a sample
• JSON EscapeEscape and unescape JSON strings
• Directory Tree GeneratorRender an indented text outline as a directory tree
• Cron Expression ParserParse a cron expression and list upcoming run times
• Regex TesterTest regular expressions with match groups and replacements
• Chmod CalculatorConvert chmod numeric and symbolic modes with explanations
• TOTP GeneratorTime-based one-time passwords (HMAC-SHA1, 2FA)
• Markdown EditorWrite Markdown with live preview and one-click copy
• HTML Entity EncoderEncode and decode HTML entities like &
• IP to Number ConverterConvert IPv4 between integer, hex and binary
• Image to Base64Convert images to Data URLs and back
• Variable Naming ConverterConvert between camelCase, snake_case and kebab-case
• Markdown TOC GeneratorGenerate an anchored table of contents from Markdown headings
• .gitignore GeneratorGenerate .gitignore files by language and framework
• robots.txt GeneratorVisually build robots.txt rules
• Meta Tag GeneratorGenerate SEO and Open Graph meta tags
• SVG MinifierStrip comments and redundant whitespace to shrink SVG files
• Nginx Config GeneratorVisually build static-site or reverse-proxy Nginx configs
• Dockerfile GeneratorGenerate ready-to-use Dockerfile templates by language
• HTML Live PreviewEdit HTML/CSS/JS on the left, rendered instantly on the right
• Keycode DetectorPress any key to see its key, code and keyCode values
• Screen RulerMeasure on-screen elements with a pixel ruler
• Viewport InfoInspect live window size, device pixel ratio and breakpoints
• Code ScreenshotTurn code snippets into shareable images with syntax highlighting themes
• PHP Serialize ConverterConvert between PHP serialize format and JSON
• SQL to Go StructGenerate Go structs with GORM tags from CREATE TABLE
• JSON to PostmanBuild a Postman Collection v2.1 from a request body, import and go
• Registry Mirror CheatsheetCopy-paste mirror commands for npm, pip, Go, Docker and more
• Redirect Code GeneratorGenerate HTML, JavaScript and Nginx redirect snippets
• MySQL Replication ConfigGenerate full primary-replica settings and CHANGE SOURCE statements
• Math Worksheet GeneratorPrintable arithmetic worksheets by grade with answer keys
• Magnet Link ConverterParse and build magnet links, convert infohash, append trackers
• JSON to C# ClassGenerate C# classes from JSON with nested types
• JSON to PHP ArrayConvert JSON to PHP array literals, ready to paste
• Truth or DareRandom truth and dare prompts for parties
• Color Name MatcherMatch a HEX value to the nearest named color
• LaTeX Table ConverterConvert between LaTeX tabular and Markdown tables
• Email Signature GeneratorBuild an HTML email signature from name, title and phone
• Keyboard TesterTest every key on your keyboard
• Map Coordinate ConverterConvert between WGS84, GCJ02 and BD09 coordinates
• Gzip Text CompressorGzip-compress text to Base64 and decompress it back
• Punycode ConverterConvert internationalized domain names to and from xn-- encoding
• Comment RemoverStrip comments from JS, CSS and HTML code
• JSON to PythonGenerate Pydantic or plain Python data models from JSON
• JSON to GoGenerate Go structs with json tags from JSON
• JSON to SQLGenerate CREATE TABLE and INSERT statements from a JSON array
• CSV to SQLTurn CSV rows into INSERT statements
• CSV to MarkdownConvert tables between CSV and Markdown
• TOML to JSONConvert TOML configuration to JSON and back
• INI to JSONConvert INI config files to JSON and back
• .env to JSONConvert environment variable files to JSON and back
• Slug GeneratorTurn titles into URL-friendly slugs
• Base32 EncoderEncode and decode text with Base32 (RFC 4648)
• Base58 EncoderEncode and decode text with the Bitcoin Base58 alphabet
• HEX ConverterConvert text to hexadecimal strings and back (UTF-8)
• ROT13Classic 13-letter rotation cipher for Latin text
• Vigenere CipherEncrypt and decrypt text with a Vigenere key
• Rail Fence CipherZigzag rail fence encryption and decryption
• Bacon CipherConvert letters to and from five-letter a/b groups
• CRC32 ChecksumCompute the CRC-32 checksum of text
• ASCII BannerRender letters and digits as 5x7 dot-matrix ASCII art
• IPv6 Expand/CompressConvert IPv6 addresses between full and compressed forms
• XML to JSONConvert XML documents to JSON, attributes prefixed with @
• HTML to MarkdownConvert HTML markup into clean Markdown
• Calendar Event GeneratorCreate .ics calendar files for any calendar app
• Cron Expression BuilderBuild cron expressions visually and preview run times
• List to SQL INJoin a list of IDs into an SQL IN clause
• Regex EscaperEscape regex special characters for safe interpolation
• CIDR CalculatorCompute subnet masks, network and host ranges
• IP Range ExpanderExpand IP ranges or CIDR blocks into single addresses
• Number Range ParserExpand expressions like 1-3,5 into a number list
• Snowflake ID GeneratorGenerate snowflake IDs in bulk for distributed systems
• Sitemap URL ExtractorExtract every URL from a sitemap XML file
• URL to SitemapBuild a sitemap XML from a list of URLs
• JSON FlattenerFlatten nested JSON to dot paths and restore it
• JSON Field ExtractorExtract JSON fields by path in bulk
• WebRTC Leak TestCheck whether WebRTC leaks your real IP address
• RSA Key GeneratorGenerate RSA key pairs locally with WebCrypto
• SVG PreviewRender SVG code instantly with live preview
• curl to CodeConvert curl commands into Python, PHP, Node, Go or Java code
• Cookie FormatterConvert cookie strings to JSON and back, with Set-Cookie attributes
• HTTP Header FormatterTurn raw request or response headers into JSON
• JSON to Query StringConvert JSON objects to URL query strings and back
• JavaScript ObfuscatorObfuscate JavaScript with string array encoding
• htaccess to NginxConvert Apache .htaccess rewrite rules to Nginx config
• GitHub TrendingWeekly GitHub trending repositories with language filters
• XPath TesterTest XPath expressions against XML or HTML live
• JSONPath TesterTest JSONPath expressions and preview results live
• JSON FixerAuto-repair broken JSON: trailing commas, single quotes, bare keys
• HTML to JSXConvert HTML fragments into React JSX
• JSON SorterRecursively sort JSON keys, arrays included
• JSON to JSONLConvert JSON arrays to JSON Lines format for LLM training
• htpasswd GeneratorGenerate htpasswd entries for basic auth
• Hill CipherMatrix-based classical cipher encryption and decryption
• SQL to Java EntityGenerate Java POJOs with comments and getters from DDL
• ULID GeneratorGenerate sortable ULIDs (timestamp + randomness) in bulk
• NanoID GeneratorGenerate NanoIDs with custom length and alphabet
• NMEA ParserParse GPS NMEA-0183 sentences: coordinates, time, satellites
• Base62/85/91 EncoderEncode text with Base62, Ascii85 and Base91
• Quoted-Printable CodecEncode and decode MIME Quoted-Printable email bodies
• Mojibake Fixer (Latin-1)Repair UTF-8 text mis-decoded as Latin-1
• Hex CalculatorHex arithmetic, bitwise ops and shifts with big integers
• IEEE 754 ConverterConvert floats to and from float32/64 bit patterns
• BCC & LRC ChecksumXOR, LRC and additive checksums for serial and Modbus frames
• Modular ExponentiationCompute a^e mod m with big integers, no size limit
• Voltage Divider CalculatorVout = R2-Vin/(R1+R2) with E12 resistor suggestions
• Voltage Drop CalculatorCable voltage drop in percent, copper or aluminum, 1P/3P
• kVA & Power FactorInterconvert kW, kVA and amps with capacitor advice
• mAh to Wh ConverterBattery charge and energy, plus runtime estimate
• AWG Wire Gauge ChartDiameter, area, resistance and ampacity for AWG 4/0-40
• Resistor Color CodeRead 4/5-band resistor values with tolerance

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