Format and minify JSON online
Make API responses, logs and configuration files easier to read.
Free Online Developer Tools — JSON, Base64, JWT and More
Use free browser-based developer tools to format JSON, encode Base64, decode JWTs, generate UUIDs and work with URLs without uploading your data.
Popular developer tasks
Start with common tools for API debugging, data conversion and test preparation. These tools run locally in your browser.
Validate JSON syntax
Find malformed JSON before sending an API request or loading configuration.
Encode text as Base64
Convert UTF-8 text into standard Base64 for development workflows.
Decode JWT headers and payloads
Inspect token claims locally without implying signature verification.
Generate secure UUID v4 values
Create identifiers for databases, APIs and test fixtures.
Encode URL parameters
Percent-encode query values, redirect URLs and path components.
Security & generators
Hashes, identifiers, tokens and authentication helpers.
UUID v4 Generator Online — Create Random UUIDs
Generate cryptographically secure UUID v4 identifiers locally in your browser. Create multiple copy-ready IDs for databases, APIs, tests and fixtures.
Open tool →Hash Generator Online — Create SHA-256 and SHA Hashes
Use this hash generator online to create SHA-1, SHA-256, SHA-384 or SHA-512 digests from UTF-8 text locally with the Web Crypto API.
Open tool →Secure Password Generator Online — Create Random Passwords
Use this secure password generator online to create a random password locally with browser cryptography, without sending it to a server.
Open tool →JWT Decoder Online — Inspect Header and Payload
Decode JWT headers and payloads locally in your browser. Inspect claims, timestamps and token structure without uploading the token or implying signature verification.
Open tool →Secure Token Generator Online — Create a 256-Bit Hex Token
Generate a cryptographically secure 256-bit random hexadecimal token locally in your browser.
Open tool →ULID Generator Online — Create Sortable Unique IDs
Generate a ULID online with a timestamp prefix and browser-random suffix, locally without an upload.
Open tool →HMAC Generator Online — Create SHA-256, SHA-384 or SHA-512
Generate an HMAC online from UTF-8 text and a secret key with the browser Web Crypto API.
Open tool →TOTP Generator Online - 6-Digit Authenticator Code
Generate a six-digit time-based one-time password from a Base32 secret locally in your browser.
Open tool →RSA Key Pair Generator Online - 2048-bit RSA-OAEP PEM
Generate an exportable 2048-bit RSA-OAEP key pair with SHA-256 locally and output PEM text.
Open tool →Password Strength Analyzer Online — Check Password Weaknesses
Estimate password strength locally using length, character variety, repetition and common-pattern checks.
Open tool →AES-GCM Encryption Online - Password Encrypt and Decrypt Text
Encrypt text with AES-256-GCM and PBKDF2 or decrypt a compatible JSON payload locally.
Open tool →Secure Random Number Generator Online — Unbiased Integers
Generate up to 1000 cryptographically secure random integers within an inclusive range.
Open tool →Converters & data
Transform structured data, numbers, dates and units.
JSON Formatter Online — Beautify and Minify JSON
Format, validate and minify JSON online in your browser. Make API responses, configuration files and logs readable without uploading your data.
Open tool →JSON Validator Online — Check JSON Syntax
Validate JSON syntax online and identify parsing errors in API payloads, configuration files and copied data without uploading the content.
Open tool →Base64 Encoder Online — Encode UTF-8 Text
Encode Unicode and UTF-8 text to Base64 online in your browser. Create Base64 values for APIs, data fields and development tasks without uploading text.
Open tool →Base64 Decoder Online — Decode Base64 to Text
Decode Base64 into readable UTF-8 text online. Inspect encoded API values, tokens and test data locally in your browser without uploading them.
Open tool →URL Encoder Online — Percent-Encode URL Components
Percent-encode URL components online in your browser. Safely prepare query values, paths and redirect parameters without uploading the source text.
Open tool →URL Decoder Online — Decode Percent-Encoded Text
Use this URL decoder online to convert percent-encoded URLs and query values into readable UTF-8 text locally in your browser.
Open tool →Case Converter Online — camelCase, snake_case and kebab-case
Use this case converter online to transform text into camelCase, snake_case, kebab-case and Title Case locally in your browser.
Open tool →Unix Timestamp Converter Online — Convert Epoch Time to Date
Use this Unix timestamp converter online to turn epoch seconds or milliseconds into an ISO date and local date without uploading data.
Open tool →Number Base Converter Online — Binary, Decimal and Hex
Convert integers online between binary, octal, decimal and hexadecimal. Process large whole numbers locally with browser BigInt.
Open tool →HEX to RGB Color Converter Online — Convert HEX, RGB and HSL
Use this HEX to RGB color converter online to turn HEX or RGB input into normalized HEX, RGB and HSL values locally in your browser.
Open tool →JSON to YAML Converter Online — Convert JSON and YAML
Convert JSON to YAML or YAML to JSON online in your browser. Format structured configuration data locally without uploading it.
Open tool →XML to JSON Converter Online — Convert XML and JSON
Convert XML to JSON or JSON to XML online in your browser. Transform structured data locally while retaining XML attributes.
Open tool →CSV to JSON Converter Online — Convert CSV and JSON
Convert CSV to JSON or JSON to CSV online in your browser. Transform tabular data locally with quoted-cell and header support.
Open tool →YAML Formatter Online — Validate and Prettify YAML
Format YAML online with consistent two-space indentation and validate its syntax locally in your browser.
Open tool →XML Formatter Online — Validate and Beautify XML
Format XML online into readable indentation while retaining elements and attributes locally in your browser.
Open tool →JSON Minifier Online — Remove JSON Whitespace
Minify JSON online by validating and removing unnecessary whitespace locally in your browser.
Open tool →Chmod Calculator Online — Convert Numeric Unix Permissions
Convert three- or four-digit chmod values into symbolic rwx permissions and a ready command locally.
Open tool →Temperature Converter Online — Celsius to Fahrenheit and Kelvin
Convert Celsius online to Fahrenheit and Kelvin with two-decimal output.
Open tool →Percentage Calculator Online — Percentage and Relative Change
Calculate what percentage one number is of another and their relative change online.
Open tool →Roman Numeral Converter Online — Numbers to Roman Numerals
Convert integers from 1 to 3999 into Roman numerals or valid Roman numerals back to integers.
Open tool →Date Converter Online — ISO, Local and Unix Time
Convert a date string or Unix timestamp into ISO, local time, Unix seconds and milliseconds.
Open tool →JSON Diff Online — Compare JSON by Property Path
Compare two JSON documents online and list changed property paths and values locally in your browser.
Open tool →REM to PX Converter Online - CSS Unit Calculator
Convert CSS px and rem values in either direction with a configurable root font size.
Open tool →Data Size Converter Online — Bytes to KB, MB, KiB and MiB
Convert bytes into decimal KB, MB, GB and binary KiB, MiB, GiB units online.
Open tool →Angle Converter Online - Degrees to Radians, Gradians and Turns
Convert a degree value into radians, gradians and full turns instantly in your browser.
Open tool →Duration Converter Online — Seconds to Minutes, Hours and Days
Convert seconds online into milliseconds, minutes, hours and days.
Open tool →JSON to TOML Converter Online — Convert Configuration Locally
Convert a JSON object to readable TOML tables and values locally in your browser.
Open tool →YAML to TOML Converter Online — Convert YAML Configuration
Convert YAML objects to readable TOML locally in your browser.
Open tool →ETA Calculator Online - Estimate Task Completion Time
Estimate remaining seconds and local completion time from completed items, total items and elapsed seconds.
Open tool →Energy Converter Online - Joules, Wh and kWh
Convert energy values among joules, kilojoules, watt-hours and kilowatt-hours.
Open tool →Power Converter Online - Watts, Kilowatts and Horsepower
Convert power values among watts, kilowatts and mechanical horsepower.
Open tool →Length Converter Online - Metric and Imperial Units
Convert length among meters, kilometers, centimeters, millimeters, inches, feet, yards and miles.
Open tool →Markdown to HTML Converter Online — Convert Markdown Locally
Convert common Markdown headings, emphasis, links, lists, quotes and code into HTML locally in your browser.
Open tool →SQL Formatter Online - Format Common SQL Clauses
Add readable line breaks around common SQL clauses, commas and AND or OR conditions locally.
Open tool →JSON Flattener Online - Flatten Objects to Property Paths
Flatten nested JSON objects and arrays into a map of dollar-prefixed dot property paths.
Open tool →JSON Key Sorter Online — Recursively Sort Object Keys
Recursively sort JSON object keys online while preserving array order and values.
Open tool →JSON Path Query Online — Read JSON by Dot or Bracket Path
Read a value from JSON using a simple dot or bracket property path locally.
Open tool →HTML to Text Converter Online - Extract Visible Page Text
Parse HTML locally, remove script, style, template and noscript elements, and return normalized body text.
Open tool →Character Code Converter Online - Text and Unicode Decimal Codes
Convert text characters to decimal Unicode code points or decimal code points back into text.
Open tool →TOML to JSON Converter Online - Parse TOML Locally
Convert supported TOML tables, dotted keys, strings, numbers, booleans, arrays and inline tables into formatted JSON.
Open tool →TOML to YAML Converter Online - Convert Configuration Locally
Parse supported TOML configuration and serialize it as readable two-space YAML.
Open tool →Math Expression Calculator Online — Safe Local Evaluator
Evaluate arithmetic expressions and common math functions locally without executing JavaScript.
Open tool →Base64 File Converter Online - Encode and Decode Files Locally
Encode a file as a Base64 data URL or decode Base64 into a downloadable browser Blob without uploading it.
Open tool →Web & network
Utilities for URLs, browsers, network data and web development.
HTML Encoder Online — Escape HTML Special Characters
Encode HTML special characters online by converting text into safe HTML entities locally in your browser.
Open tool →HTML Entity Decoder Online — Decode HTML to Text
Decode HTML entities online into readable characters locally in your browser, including common named and numeric references.
Open tool →Regex Tester Online — Test JavaScript Regular Expressions
Use this regex tester online to run JavaScript regular expressions against sample text and inspect matches, indexes and capture groups locally.
Open tool →Cron Expression Parser Online — Explain Five Cron Fields
Parse a standard five-field cron expression online and label its minute, hour, day, month and weekday fields.
Open tool →QR Code Generator Online — Create and Download QR Codes
Use this free QR code generator online to create a downloadable 512-pixel PNG from text or a URL locally in your browser.
Open tool →Basic Auth Header Generator Online — Create Authorization Header
Generate an HTTP Basic Authorization header from a UTF-8 username and password locally in your browser.
Open tool →Random Port Generator Online - Generate an Unprivileged Port
Generate one random TCP or UDP port number from the unprivileged range 1024 through 65535.
Open tool →URL Parser Online — Break a URL into Components
Parse a URL online into protocol, host, port, path, query parameters and fragment locally in your browser.
Open tool →IPv4 Address Converter Online - Decimal, Hex and Binary
Convert a dotted IPv4 address into its unsigned decimal, hexadecimal and 32-bit binary representations.
Open tool →Random MAC Address Generator Online — Locally Administered MACs
Generate up to 50 random locally administered unicast MAC addresses with browser cryptographic randomness.
Open tool →Device Information Checker Online - Browser, Screen and Time Zone
View browser-exposed user agent, language, platform, screen, connectivity and time-zone information locally.
Open tool →CSS Formatter Online — Beautify Compact CSS
Format compact CSS online into readable rules and declarations locally in your browser.
Open tool →Outlook Safe Link Decoder Online - Extract the Original URL
Extract the encoded destination URL from a Microsoft Outlook Safe Links address without opening it.
Open tool →IPv4 Subnet Calculator Online — Calculate CIDR Ranges
Calculate IPv4 network, netmask, broadcast, host range and address counts from CIDR notation locally.
Open tool →URL Defanger Online - Defang and Refang Links
Convert http links into hxxp and dot-bracket notation, or restore that notation for security analysis.
Open tool →Query String Converter Online — Query Parameters to JSON
Convert URL query strings to JSON or JSON objects to encoded query strings locally.
Open tool →CSS Minifier Online — Remove CSS Comments and Whitespace
Minify CSS online by removing comments and unnecessary whitespace locally in your browser.
Open tool →HTML Minifier Online — Compress HTML Markup
Minify HTML online by removing ordinary comments and whitespace between tags locally in your browser.
Open tool →User-Agent Parser Online — Detect Browser and Operating System
Parse a User-Agent string online to identify common browsers, engines, operating systems and mobile hints locally.
Open tool →HTTP Status Codes Reference Online — Look Up Response Codes
Look up common HTTP status codes and meanings online, including 2xx, 3xx, 4xx and 5xx responses.
Open tool →WCAG Color Contrast Checker Online — Test HEX Colors
Check the WCAG contrast ratio between two HEX colors and test AA and AAA text thresholds locally.
Open tool →IBAN Validator Online - Check and Parse an IBAN
Normalize an IBAN, validate its basic structure and MOD 97 checksum, and display country and check digits.
Open tool →IPv6 ULA Generator Online - Create a Random /48 Prefix
Generate a random locally assigned IPv6 Unique Local Address prefix beginning with fd and ending in /48.
Open tool →Open Graph Meta Tag Generator Online - Create Social Tags
Generate escaped Open Graph and Twitter card meta tags from a small JSON object.
Open tool →SVG Placeholder Generator Online - Create Lightweight Placeholders
Create a simple SVG placeholder from width, height, background color and label text.
Open tool →MIME Type Lookup Online - Search File Content Types
Look up common MIME types by extension or by a partial content-type value.
Open tool →Docker Run to Compose Converter Online - Generate Compose YAML
Convert a supported docker run command into a simple Docker Compose service definition.
Open tool →IPv4 Range Expander Online - List Addresses Between Two IPs
Expand an inclusive start and end IPv4 range into one dotted address per line.
Open tool →Wi-Fi QR Code Generator Online — Create Network QR
Generate a downloadable Wi-Fi connection QR code from SSID, password, security and hidden-network settings locally.
Open tool →Git Command Reference Online - Search Common Git Commands
Search a concise local reference of common Git status, staging, history, branch, remote and recovery commands.
Open tool →Regex Cheat Sheet Online - Search JavaScript Syntax
Search a compact JavaScript regular expression reference for classes, anchors, groups, lookaheads, quantifiers and flags.
Open tool →Character Encoding Info Online - Unicode, UTF-8 and UTF-16
Inspect the first entered character as a Unicode code point plus UTF-8 and UTF-16 numeric units.
Open tool →Hyperfine Benchmark Command Builder Online - Compare Commands
Build a quoted hyperfine command from one or more shell commands plus run and warmup counts.
Open tool →Online Chronometer - Browser Stopwatch with Milliseconds
Measure elapsed time with a local browser stopwatch that supports start, pause, resume and reset.
Open tool →HTML WYSIWYG Editor Online - Edit Rich Text and Copy HTML
Edit formatted content visually with bold, italic, underline, heading and paragraph controls, then copy generated HTML.
Open tool →PDF Signature Structure Checker Online - Inspect Embedded Signatures
Inspect a PDF locally for signature dictionaries, ByteRange values and SubFilter identifiers without uploading it.
Open tool →Text utilities
Analyze, compare, normalize and generate text.
Word and Character Counter Online — Count Text Instantly
Use this word and character counter online to count characters, words and lines instantly in your browser without uploading text.
Open tool →Text Diff Online — Compare Text Line by Line
Compare two text blocks online and identify changed lines locally in your browser.
Open tool →Slug Generator Online — Convert Text to URL Slugs
Generate a clean lowercase URL slug online from text, including Latin letters, numbers and Chinese characters.
Open tool →Numeronym Generator Online - Create i18n-Style Abbreviations
Turn long alphabetic words into numeronyms such as internationalization to i18n directly in your browser.
Open tool →Text to Binary Converter Online — UTF-8 Binary to Text
Convert UTF-8 text to eight-bit binary bytes or binary bytes back to text locally.
Open tool →Unicode Converter Online — Text to Unicode Code Points
Convert text to U+ Unicode code points or code points back to text locally in your browser.
Open tool →String Obfuscator Online - Mask Sensitive Text
Mask the middle of a string while retaining a small prefix and suffix for recognizable sharing.
Open tool →Lorem Ipsum Generator Online — Create Placeholder Paragraphs
Generate one to twenty Lorem Ipsum placeholder paragraphs locally in your browser.
Open tool →Email List Normalizer Online - Lowercase, Deduplicate and Sort
Normalize an email list by splitting common separators, lowercasing, validating, deduplicating and sorting addresses.
Open tool →List Cleaner Online — Trim, Deduplicate and Sort Lines
Clean a line-based list online by trimming, removing blanks, deduplicating and naturally sorting it.
Open tool →NATO Phonetic Alphabet Converter Online - Text to Alfa Bravo
Convert letters into NATO spelling alphabet words for clearer voice communication.
Open tool →Morse Code Converter Online - Text to Morse and Back
Convert English letters and digits to International Morse code or decode spaced Morse code into text.
Open tool →Word Frequency Counter Online - Count and Rank Words
Count repeated Unicode words and numbers in text, then rank them by frequency locally.
Open tool →Phone Number Formatter Online - Normalize Readable Digits
Remove punctuation from a 7-to-15-digit phone number and display E.164-like and grouped readable forms.
Open tool →Line Sorter Online — Natural Sort Text Lines
Sort text lines online with case-insensitive, numeric-aware natural ordering.
Open tool →Duplicate Line Remover Online — Deduplicate Text Lines
Remove duplicate text lines online while preserving the first occurrence and original order.
Open tool →Emoji Picker Online - Search Common Emoji by Keyword
Search a compact built-in emoji catalog by English keyword and copy matching characters locally.
Open tool →ASCII Text Art Generator Online - Draw Letters with Hash Symbols
Turn up to twenty letters, digits or spaces into five-row hash-sign banner text locally.
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