Developer and data utilities
Format and validate JSON, decode JWTs, test regular expressions, hash strings, generate UUIDs, read cron expressions, convert between CSV, YAML and XML, and calculate subnets. Every tool here runs locally, so tokens and production data never leave the tab.
- Tools
- 42
- Run on your device
- 42
- Signup required
- No
QR Code Generator
Generates high-resolution QR codes for URLs, Wi-Fi credentials, contact details, or plain text, ready to download as a PNG.
QR & Barcode Reader
Decodes QR codes and common barcode formats from an uploaded image file, or straight from a live device camera feed instantly.
Unit Converter
Converts length, weight, volume, and temperature values between the metric and imperial measurement systems instantly as you type.
Currency Converter
Converts between world currencies using current reference exchange rates, refreshed automatically on a regular schedule.
Color Converter
Converts colors between HEX, RGB, and HSL formats, showing a live color swatch preview updated as you edit each of the values.
JSON ⇄ CSV
Converts JSON arrays into CSV spreadsheets, or CSV files back into JSON, correctly handling quoted, escaped, and nested values.
Base64 Encoder / Decoder
Encodes plain text or files into Base64, or decodes existing Base64 strings back into their original readable text form.
Unix Timestamp Converter
Converts between Unix timestamps and human-readable calendar dates in either direction, with full local timezone support built in.
Password Generator
Generates strong, random passwords with a custom length and character set, computed locally and never sent anywhere at all.
UUID Generator
Generates one or many random version-4 UUIDs (GUIDs) instantly, ready to copy straight into your code or database schema.
Hash Generator
Computes SHA-1, SHA-256, SHA-384, and SHA-512 hashes for any text string or uploaded file, right inside your own browser.
Word & Character Counter
Counts words, characters, sentences, and paragraphs in any block of pasted text, plus an estimated reading time for the piece.
JSON Formatter & Validator
Validates and pretty-prints JSON with custom indentation, pointing out the exact line and column of any parse error found.
Text Case Converter
Converts text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, and kebab-case formatting styles instantly.
URL Encoder / Decoder
Encodes or decodes URL components and query strings, correctly handling special characters, spaces, and reserved symbols.
JWT Decoder
Decodes a JWT's header and payload into readable JSON; this checks the token structure only, not the signature's validity.
Regex Tester
Tests regular expressions against sample text with live match highlighting and a full breakdown of each capture group found.
Text Diff Checker
Compares two blocks of text line by line and clearly highlights exactly what was added, removed, or changed between them.
Lorem Ipsum Generator
Generates placeholder Lorem Ipsum text as paragraphs, sentences, or individual words for mockups and layout testing work.
Number Base Converter
Converts numbers between binary, octal, decimal, and hexadecimal number systems instantly as you type each value into the field.
Text to Speech
Reads any text aloud using your browser's built-in voice engine, completely free and with nothing ever uploaded anywhere.
Timezone Converter
Converts a date and time between PST, CST, EST, UTC, and dozens of other zones, handling daylight saving changes automatically.
CSV ⇄ Excel
Converts CSV files into full Excel spreadsheets, or existing Excel workbooks back into plain, portable CSV text data files.
CSV Cleaner & Deduper
Cleans, deduplicates, transforms, and validates CSV data in bulk before exporting a corrected, ready-to-use output file.
YAML ⇄ JSON
Converts YAML configuration files into JSON, or JSON objects back into readable, properly indented YAML syntax instantly.
XML ⇄ JSON
Converts XML documents into JSON, or JSON objects back into well-formed XML markup with correct nested element structure.
Markdown to HTML
Converts Markdown source text into clean, ready-to-use HTML markup for publishing on websites, blogs, and inside emails.
HTML to Markdown
Converts HTML markup back into clean Markdown source, stripping out unnecessary tags and inline formatting along the way.
Cron Expression Parser
Turns a cron expression into a plain-English description of exactly when and how often that scheduled job will actually run.
IP Subnet Calculator
Calculates the network range, subnet mask, broadcast address, and total usable host count from any IPv4 CIDR block you enter.
Geo/IP Lookup
Looks up an IP address's approximate geographic location, ASN number, network owner, and local timezone information for you.
JSON Diff
Compares two JSON objects side by side and highlights every key, value, and structural difference found between the two.
CSV Diff
Compares two CSV files row by row and clearly highlights exactly which rows were added, removed, or changed between them.
Barcode Generator
Generates CODE128, EAN-13, UPC, CODE39, or ITF-14 barcodes from your input text and downloads each one as a PNG image file.
Markdown Table Generator
Turns CSV or tab-separated data into a properly aligned, ready-to-paste Markdown table for docs, wikis, and README files.
Slug Generator
Converts any piece of text into a clean, lowercase, URL-friendly slug suitable for links, page routes, and file names in one step.
Text Encrypt / Decrypt
Encrypts or decrypts text using a chosen password with AES-GCM encryption; the whole process runs locally and is never uploaded.
vCard Generator
Creates a downloadable vCard (.vcf) contact file built from a name, phone number, email address, and other custom fields.
JSON to TypeScript
Turns a JSON object into ready-to-use TypeScript interfaces, inferring nested object types automatically as it walks the structure.
SQL Formatter
Formats and indents messy SQL queries for MySQL, PostgreSQL, SQLite, T-SQL, and standard ANSI SQL syntax with one click.
JS / CSS / HTML Minifier
Minifies JavaScript, CSS, or HTML source code, producing smaller, faster-loading files that are ready to deploy to production.
Color Contrast Checker
Checks the WCAG contrast ratio between a foreground and background color against both the AA and AAA accessibility thresholds.
Other categories
Last updated 2026-08-03