Developer & Utility
Generators, encoders and handy everyday utilities.
What are developer and utility tools?
Developer and utility tools handle everyday formats and checks in the browser: JSON formatting and schema generation, MD5 and SHA hashes, Base64 encoding, strong password generation, test card numbers and browser, user-agent and screen details.
| I want to… | Use this tool |
|---|---|
| Format and validate JSON | JSON Formatter & Validator |
| Generate SHA-256 or MD5 hashes | MD5 & SHA Hash Generator |
| Encode or decode Base64 | Base64 Encoder / Decoder |
| Create a strong random password | Strong Password Generator |
JSON to JSON Schema
Generate a JSON Schema (draft 2020-12) from any JSON sample.
JSON Formatter & Validator
Beautify, minify and validate JSON with clear error messages.
MD5 & SHA Hash Generator
Generate MD5, SHA-1, SHA-256 and SHA-512 hashes.
Base64 Encoder / Decoder
Encode or decode Base64 text (UTF-8 safe).
Strong Password Generator
Generate secure random passwords in your browser.
Credit Card Generator (Test Numbers)
Generate Luhn-valid dummy card numbers for testing payment forms.
Credit Card Validator
Validate a card number with the Luhn check and detect its brand.
User Agent Detector
See and decode your browser user agent string.
What Is My Browser
Details about your browser, OS, screen, language and capabilities.
Screen Resolution Detector
Find your screen resolution, viewport and pixel ratio.
JSON to CSV Converter
Convert a JSON array to CSV, with nested objects flattened into columns.
CSV to JSON Converter
Convert CSV to a JSON array, with header detection, quoted fields and number parsing.
JSON to YAML Converter
Convert JSON to clean, readable YAML.
YAML to JSON Converter
Convert YAML (including multi-document files) to JSON and validate the syntax.
JSON to XML Converter
Convert JSON to well-formed XML, with @attributes and a custom root element.
XML to JSON Converter
Convert XML to JSON, keeping attributes, repeated elements and text.
XML Formatter & Validator
Beautify or minify XML and check it is well-formed.
JSON to TypeScript Interface
Generate TypeScript interfaces from a JSON sample, including nested objects and arrays.
HTML Beautifier
Format messy or minified HTML with clean indentation.
HTML Minifier
Minify HTML safely: remove comments and whitespace while keeping pre, textarea, script and style intact.
CSS Beautifier
Format minified or messy CSS into readable, indented code.
CSS Minifier
Minify CSS with the csso optimiser to make stylesheets smaller and faster.
JavaScript Beautifier
Format minified or messy JavaScript into readable code.
JavaScript Minifier
Minify JavaScript with Terser: compress, mangle names and strip comments.
SQL Formatter
Format SQL queries for MySQL, PostgreSQL, SQL Server, SQLite, BigQuery and more.
Markdown to HTML Converter
Convert Markdown (GitHub-flavoured) to HTML with a live, safe preview.
HTML to Markdown Converter
Convert HTML to clean Markdown with headings, lists, links, tables of text and code blocks.
HTML Viewer (Online HTML Editor)
Paste HTML, CSS and JavaScript and see it rendered instantly in a secure sandbox.
Regex Tester
Test regular expressions with live match highlighting, groups and replace — safely, with a timeout.
JWT Decoder & Verifier
Decode JSON Web Tokens, check expiry and verify HS, RS, PS and ES signatures — all in your browser.
UUID Generator (v4 & v7)
Generate random v4 or time-ordered v7 UUIDs in bulk, with formatting options.
Unix Timestamp Converter
Convert Unix timestamps (seconds, milliseconds, microseconds) to dates and dates to timestamps.
Cron Expression Explainer
Translate a cron expression into plain English and see the next 10 run times.
Chmod Calculator
Convert Linux file permissions between octal (755) and symbolic (rwxr-xr-x) form.
Bcrypt Hash Generator & Checker
Create bcrypt password hashes with a chosen cost, or verify a password against a hash.
Htpasswd Generator
Create a secure bcrypt .htpasswd line and .htaccess rules to password-protect a folder.
HTML Entity Encoder / Decoder
Encode special characters as HTML entities or decode entities back to text.
HMAC Generator
Generate HMAC-SHA1, SHA256, SHA384 or SHA512 signatures in hex and Base64.
Number Base Converter
Convert numbers between binary, octal, decimal, hex and any base from 2 to 36 — even very large numbers.
Text to Binary Converter
Convert text to binary (UTF-8) and binary back to text.
Text to Hex Converter
Convert text to hexadecimal (UTF-8 bytes) and hex back to text.
Password Strength Checker
Check how strong a password is: entropy, cracking time and common weaknesses — privately in your browser.
IP Subnet Calculator (CIDR)
Calculate network, broadcast, host range, mask and wildcard for any IPv4 CIDR — and split it into smaller subnets.
IPv6 Address Expander & Compressor
Expand or compress an IPv6 address, see its type, reverse DNS name and prefix range.
MAC Address Formatter & Generator
Convert a MAC address between colon, hyphen and Cisco formats, check its type, or generate a random MAC.
HTTP Status Codes List & Lookup
Look up any HTTP status code (200, 301, 404, 503…) with its meaning and SEO impact, or browse the full list.
MIME Type Lookup
Find the MIME (Content-Type) for a file extension, or the extensions for a MIME type, with server config lines.
JSON Diff (Compare JSON)
Compare two JSON documents and list every added, removed and changed value by its path.
Test Data Generator (Fake JSON, CSV, SQL)
Generate realistic fake user records as JSON, CSV or SQL inserts for testing and demos.
Barcode Generator (Code 128, EAN-13, UPC)
Create Code 128, EAN-13, EAN-8, UPC-A, Code 39, ITF-14 and more barcodes — download as PNG or SVG.
Markdown Table Generator
Turn CSV or cells copied from Excel / Google Sheets into a neatly aligned Markdown table.
HTML Table Generator
Convert CSV or spreadsheet cells into clean, accessible HTML table code with a live preview.
IBAN Validator
Check whether an IBAN is valid: country, length and MOD-97 check digits, with the bank and account part split out.
SSH Key Generator (RSA, Ed25519)
Generate an SSH key pair (Ed25519 or RSA 2048/4096) in OpenSSH format, right in your browser.
cURL to Code Converter
Convert curl commands to JavaScript fetch, Python requests, PHP cURL and Node.js axios code.
Popular
JSONPath Tester
Test JSONPath expressions against your JSON and see every matching value and its path.
XPath Tester
Run XPath queries on HTML or XML and list matching elements, attributes and text.
Crontab Generator
Build a cron schedule line with presets or custom fields, see the next run times and stop cron emails.
Docker Run to Compose Converter
Convert a docker run command into a docker compose.yaml service with ports, volumes and environment.
String Escape & Unescape
Escape or unescape text for JSON, JavaScript, HTML, XML, SQL, CSV, regex, shell and Unicode.
TOTP / 2FA Code Generator
Generate live 2FA codes (TOTP) from a Base32 secret, or create a new secret with an authenticator QR code.
ASCII Table & Character Codes
Full ASCII table (0–127) with decimal, hex, octal, binary and HTML codes — or look up any character.
SSL Certificate Decoder
Decode a PEM SSL/TLS certificate: domains (SANs), issuer, validity dates, key size and fingerprints.
CSR Decoder
Decode a certificate signing request (CSR) to check its common name, organisation, SANs and key strength before ordering SSL.
CSV to SQL Converter
Convert CSV into SQL CREATE TABLE and INSERT statements for MySQL, PostgreSQL, SQLite or SQL Server.
Base32, Base58 & Base85 Encoder / Decoder
Encode and decode text with Base32, Base58 (Bitcoin), Ascii85, Base36, Base64URL or hex.
HTML to JSX Converter
Convert HTML into React JSX: className, htmlFor, style objects, self-closing tags and event handlers.
Code to Image (Code Screenshot)
Turn code into a beautiful syntax-highlighted image with a window frame and gradient — perfect for social posts.
JSON to Go, Python, Java, C# Classes
Generate Go structs, Python dataclasses, Java, C#, Rust, Kotlin or PHP classes from a JSON sample.
ULID, NanoID & UUID v7 Generator
Generate ULIDs, NanoIDs, MongoDB ObjectIds and time-ordered UUID v7 identifiers in bulk.
WebSocket Tester
Connect to a WebSocket (wss://) server, send messages and watch the replies live in your browser.
IP Range to CIDR Converter
Convert an IPv4 range into the minimal list of CIDR blocks, or CIDR blocks into IP ranges.
File Checksum Calculator (MD5, SHA-256)
Calculate MD5, SHA-1, SHA-256, SHA-512 and CRC32 checksums of any file, and verify a download.
Nginx Config Generator
Generate an nginx server block for PHP, static sites, SPAs or reverse proxies — HTTPS, redirects, gzip and caching.
.gitignore Generator
Create a .gitignore file for Node, Python, PHP, Laravel, WordPress, Java, .NET, Go, Rust, editors and operating systems.
Open Source License Generator
Generate a LICENSE file — MIT, Apache 2.0, GPL-3.0, BSD, ISC, MPL-2.0, Unlicense — with your name and year.
Semver Checker (Version Range Tester)
Check if a version satisfies an npm semver range (^, ~, x, >=, ||), compare versions and get the next version.
Hex Viewer (Hex Dump)
View any file as a hex dump with offsets and ASCII, and identify its real type from the magic bytes.
JavaScript Keycode Tester
Press any key to see its event.key, event.code, keyCode and modifiers — the JavaScript keycode reference.
API Tester (Online REST Client)
Send GET, POST, PUT, PATCH and DELETE requests with headers and a JSON body, and inspect the response.
Popular
CORS Tester
Test whether a URL’s CORS headers let a browser on another origin call it — preflight and actual request.
MAC Address Vendor Lookup
Find the manufacturer of any MAC address from the official IEEE OUI registry — bulk lookup up to 100.
.env to JSON Converter
Convert .env files to JSON and JSON back to .env — handles quotes, comments, export and nested keys.
Binary Calculator
Add, subtract, multiply and divide binary, octal or hex numbers and run AND, OR, XOR, NOT and bit shifts — any size.
ISBN Validator & Converter
Validate ISBN-10 and ISBN-13 numbers, fix the check digit and convert between ISBN-10 and ISBN-13.