JSON Formatter
Format valid JSON with 2 or 4 spaces and pinpoint common syntax errors.
Open toolOnline Developer Tools
A collection of 60 developer tools for data processing, code formatting, hashing, text conversion, HTTP workflows, and local IP network calculations.
Every tool runs locally in your browser with no sign-in, backend, or online API, so your input is never uploaded by the tool.
JSON & Data Tools
JSON Validator
Validate JSON syntax with a clear status, error reason, and precise location.
Open toolJSON Minifier
Parse and reserialize JSON into one reliable line while calculating size savings.
Open toolJSON Viewer
Switch between raw JSON and a collapsible tree with clear value-type highlighting.
Open toolJSON → CSV
Convert arrays of objects to standard CSV with correct quoting, commas, line breaks, and missing fields.
Open toolCSV → JSON
Parse CSV using RFC 4180 conventions, including quoted commas, line breaks, and escaped quotes.
Open toolXML & YAML Tools
XML Formatter
Validate and pretty-print XML while preserving attributes, comments, and CDATA.
Open toolXML → JSON
Convert XML nodes, attributes, text, and repeated elements to predictable JSON.
Open toolJSON → XML
Recursively convert objects and arrays, escape text, and reject invalid XML tag names.
Open toolYAML → JSON
Convert YAML objects, arrays, and scalar values to JSON and report syntax errors.
Open toolJSON → YAML
Turn standard JSON into readable YAML with correct handling for objects, arrays, and scalar values.
Open toolEncoding & Text Conversion
Base64 Encode
Encode UTF-8 text as Base64 with support for international characters and emoji.
Open toolBase64 Decode
Validate Base64 input and decode it back into multilingual Unicode text.
Open toolURL Encode
Encode international text and special characters in URL Component or Full URL mode.
Open toolURL Decode
Decode percent-encoded text and report incomplete or invalid sequences clearly.
Open toolHex → Text
Strictly parse hexadecimal bytes and restore to multilingual text as UTF-8.
Open toolText → Hex
Encode Unicode text into UTF-8 bytes and output in three common hexadecimal formats.
Open toolBinary → Text
Parses binary strictly as 8-bit bytes and decodes to readable text using UTF-8.
Open toolText → Binary
Encode Unicode text into UTF-8 bytes, and then output a fixed eight-bit binary.
Open toolASCII Converter
Convert between characters, ASCII decimal, hexadecimal, and binary, and mark non-ASCII characters.
Open toolUnicode Converter
View encoding information one by one Unicode Code Point, and support U+ and JavaScript escape and reverse conversion.
Open toolHTML Entity Encoder
Encode special characters commonly found in HTML, and optionally convert non-ASCII characters into numeric entities.
Open toolHTML Entity Decoder
Decode named and numeric HTML Entities and safely display the results as textContent.
Open toolDeveloper Utilities
Regex Tester
Test flags, match indexes, and capture groups with a time-limited worker for complex patterns.
Open toolUUID Generator
Generate 1–100 cryptographically random UUID v4 values with case and hyphen options.
Open toolUnix Timestamp Converter
Convert between Unix seconds, milliseconds, and dates with device time zone, UTC, and ISO output.
Open toolCode Formatters
HTML Formatter
Format complete HTML documents and common snippets with Prettier.
Open toolCSS Formatter
Format CSS selectors, declarations, media queries, keyframes, and custom properties.
Open toolJavaScript Formatter
Format modern JavaScript with Prettier, including classes, optional chaining, and async/await.
Open toolSQL Formatter
Format queries for Standard SQL, MySQL, PostgreSQL, or SQLite.
Open toolCode Minifiers
HTML Minifier
Minify HTML while preserving preformatted content and meaningful inline spacing.
Open toolCSS Minifier
Minify CSS with a syntax tree that understands strings, calc(), and custom properties.
Open toolJavaScript Minifier
Parse, compress, and mangle modern JavaScript with Terser while showing size changes.
Open toolHash & Security Tools
SHA256 Generator
Generate a 64-character hexadecimal SHA-256 digest from UTF-8 text using the browser's built-in Web Crypto API.
Open toolSHA512 Generator
Generate a 128-character hexadecimal SHA-512 digest from UTF-8 text using Web Crypto.
Open toolMD5 Generator
Compute a 32-character hexadecimal MD5 digest from UTF-8 text with a local implementation, for compatibility checks—not security.
Open toolFile Hash Calculator
Select a local file and calculate SHA-256, SHA-512 or MD5 within the browser, no upload required.
Open toolJWT Decoder
Locally decodes JWT Header and Payload, and interprets common Unix time claims; does not verify signatures.
Open toolBasic Auth Generator
Generate Basic Authorization Header securely in UTF-8, with the caveat that Base64 is not encryption.
Open toolCron & Time Expressions
URL & HTTP Tools
Query String Parser
Parse a query string while preserving repeated parameters, empty values, and standard percent-encoding behavior.
Open toolQuery String Generator
Generates a correctly encoded Query String from multi-line key-value parameters, allowing duplicate Keys.
Open toolURL Parser
Split full or relative URLs and list query parameters with the native URL API.
Open toolCookie Parser
Parses the pasted Cookie Header and displays the original value and secure decoding results side by side.
Open toolHTTP Header Parser
Parses plain text HTTP headers, preserving colons in repeated fields and values, and outputs JSON.
Open toolHTTP Request Helpers
Curl Generator
Generates correctly escaped cURL commands from structured request information, but does not execute the request.
Open toolCurl → Fetch
Safely parse common cURL commands into fetch code and explicitly report unsupported options.
Open toolFetch → Curl
Safely parses common fetch calls and generates cURL; does not use eval or new Function.
Open toolFile Type Tools
MIME Type Lookup
Look up file extensions and MIME types in either direction, or search by keyword, using a local mapping.
Open toolNetwork & IP Calculation Tools
IPv4 Validator
Strictly validate A.B.C.D notation, the 0 to 255 range, and leading-zero rules, then view each octet and the 32-bit binary representation.
Open toolIPv6 Validator
Parse and validate full, compressed, and IPv4-mapped IPv6 addresses, then generate expanded and canonical compressed forms.
Open toolIPv4 → Binary
Convert the four decimal IPv4 octets to fixed-width 8-bit binary, with both dotted and continuous output.
Open toolBinary → IPv4
Validate exactly 32 binary digits, then convert continuous, dotted, or whitespace-grouped binary input to IPv4.
Open toolCIDR Calculator
Calculate the subnet mask, network and broadcast addresses, address range, and host counts from an IPv4 address and CIDR prefix.
Open toolSubnet Calculator
Perform comprehensive subnet calculations using a CIDR prefix or contiguous subnet mask, including boundaries, bit counts, and the host range.
Open toolSubnet Mask Calculator
Convert between CIDR prefixes and subnet masks, with strict validation that the binary 1s and 0s are contiguous.
Open toolIP Range Calculator
Calculate a CIDR block's start and end addresses, usable range, and counts without expanding it into a large IP list.
Open toolNetwork Address Calculator
Precisely calculate the network address with IP AND Subnet Mask, and view the three-line binary operation.
Open toolBroadcast Address Calculator
Precisely calculate the broadcast address using Network OR Wildcard, and view the binary operation.
Open tool