JSON tool · Runs in your browser
JSON Formatter
Format JSON online: beautify messy JSON with 2 or 4 spaces or tabs, sort keys, minify it to one line and find errors. Free, runs in your browser.
Free Online Tools
Quick tools for the jobs that come up while building apps and websites: turn JSON into model classes, check a domain's DNS and headers, test redirects and robots.txt, and more. Free, with no sign-up, and most of them run right in your browser.
JSON tools
11 tools
JSON and code models
JSON tool · Runs in your browser
JSON Validator
Check if JSON is valid and see the exact line and column of any error, with a hint on how to fix it. A free online JSON validator in your browser.
JSON tool · Runs in your browser
JSON to Kotlin Data Class
Paste JSON and get Kotlin data classes for Android, with kotlinx.serialization, Gson or Moshi names, nullable fields and defaults. Free, in your browser.
JSON tool · Runs in your browser
JSON to Dart (Flutter)
Convert JSON to null-safe Dart model classes for Flutter, with fromJson, toJson and an optional copyWith. Free, no sign-up, runs in your browser.
JSON tool · Runs in your browser
JSON to Swift (Codable)
Turn JSON into Swift Codable structs or classes, with CodingKeys for snake_case keys. Free JSON to Swift converter for iOS and macOS apps.
JSON tool · Runs in your browser
JSON to Java Class (POJO)
Convert JSON to Java classes: a POJO with getters and setters, Lombok @Data or a record, with Gson or Jackson names. Free, runs in your browser.
JSON tool · Runs in your browser
JSON to TypeScript
Turn JSON into TypeScript interfaces or types, with export, optional and readonly options. A free JSON to TypeScript converter that runs in your browser.
JSON tool · Runs in your browser
JSON to Go Struct
Turn JSON into Go structs with json tags and omitempty, ready for encoding/json.
JSON tool · Runs in your browser
JSON to C# Class
Generate C# classes or records from JSON with JsonPropertyName or JsonProperty attributes, for .NET, Unity and Xamarin.
JSON tool · Runs in your browser
JSON to Python Class
Convert JSON to Python dataclasses, Pydantic models or TypedDicts with type hints and Optional fields.
JSON tool · Runs in your browser
JSON to SQL
Convert a JSON array into a MySQL, PostgreSQL or SQLite CREATE TABLE statement and INSERT rows.
Network tools
4 tools
Domain, server and network
Network tool · Checks live sites
DNS Lookup
Check any domain's DNS records online: A, AAAA, CNAME, MX, NS, TXT, SOA and CAA. See where a domain points, its mail servers and its nameservers.
Network tool · Checks live sites
HTTP Headers Checker
Check the HTTP response headers of any URL: status code, server, caching, Last-Modified, redirects and security headers like HSTS and CSP. Free.
Network tool · Checks live sites
Redirect Checker
Trace every redirect of a URL: each hop's status code (301, 302, 307, 308), its Location, the server and meta refresh. Find redirect chains and loops.
Network tool · Checks live sites
What Is My IP
See your public IP address (IPv4 or IPv6), its reverse host name, and what your browser tells websites. Works on phones and computers.
SEO tools
5 tools
SEO and AI search
SEO tool · Checks live sites
Robots.txt Checker
Test if robots.txt blocks a URL for Googlebot, Bingbot or AI crawlers like GPTBot and ClaudeBot. See the rule that matches and the sitemaps listed.
SEO tool · Runs in your browser
Robots.txt Generator
Create a robots.txt file: block folders, add your sitemap, and allow or block AI crawlers such as GPTBot, ClaudeBot and PerplexityBot.
SEO tool · Runs in your browser
llms.txt Generator
Create an llms.txt file for your website in a minute: name, summary, details and sections of links in the right Markdown format. Free, with an example.
SEO tool · Runs in your browser
Meta Tag Generator
Generate HTML meta tags for SEO and sharing: title, description, robots, canonical, Open Graph and Twitter cards, with a Google preview. Free.
SEO tool · Checks live sites
Open Graph Checker
Preview how a link looks when shared on Facebook, WhatsApp, LinkedIn and X, and check every Open Graph and Twitter Card tag.
Developer tools
8 tools
Developer tools
Developer tool · Runs in your browser
Password Generator
Generate strong random passwords of 16, 18, 25 or up to 64 characters with uppercase, lowercase, numbers and symbols. Free and made in your browser.
Developer tool · Runs in your browser
Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to text, with full UTF-8 support and a URL-safe option.
Developer tool · Runs in your browser
Hash Generator
Create MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text instantly in your browser.
Developer tool · Runs in your browser
UUID Generator
Generate random version 4 UUIDs (GUIDs) in bulk, in lowercase or uppercase, with or without hyphens.
Developer tool · Runs in your browser
URL Encode / Decode
Percent-encode text for safe use in URLs and query strings, or decode %20-style URLs back to readable text.
Developer tool · Runs in your browser
Unix Timestamp Converter
Convert Unix epoch timestamps (seconds or milliseconds) to readable dates in your time zone and UTC, and dates back to timestamps.
Developer tool · Runs in your browser
QR Code Generator
Create QR codes for links, text, Wi-Fi, phone numbers and email. Choose colours and size, then download as PNG or SVG.
Developer tool · Runs in your browser
Slug Generator
Convert any title into a clean, lowercase, SEO-friendly URL slug with hyphens. Removes accents, symbols and stop words.
Image tools
3 tools
Image tools
Image tool · Runs in your browser
Image Compressor
Compress images to a smaller file size with a quality slider and live before/after size. Works offline in your browser.
Image tool · Runs in your browser
Image Resizer
Resize images to exact pixels or a percentage, keep the aspect ratio and download as JPG, PNG or WebP. No upload needed.
Image tool · Runs in your browser
Image Converter
Convert images between JPG, PNG and WebP in your browser, including batches of several files.
About these tools
We build Android apps, websites and servers for a living, and these are the small tools we reach for every day. Tools that work on text or files run in your browser, so your data never leaves your device. The domain, header, redirect and robots.txt tools ask our server to fetch public information only, and nothing you type is stored.
Each tool links to one of our guides that shows the job it helps with, from connecting a domain to hosting to securing an Ubuntu server.