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Developer tools that just work

Format and validate JSON, convert CSV and XML, encode and decode data, test APIs, build campaign links and more. 74 tools in 11 categories. Paste your input and get the result instantly. Your data stays on your device.

Browse by category Try JSON Formatter
API Testing1 Converter13 Developer7 Difference1 Encoder7 Formatter4 Generator6 Marketing16 SEO2 Text Tool9 URL Tool8

A CodeBySDE project

74Toolsand more added regularly
11Categoriesfrom formatters to marketing
PrivateBy designyour input stays on your device
FreeNo sign-upno account, trial or limits

Popular

JSON Formatter

Beautify and validate JSON data online.

Url Pro Analyzer

Analyze, decode, and manipulate URLs like a pro.

JSON Difference Checker

Compare and highlight differences between two JSON objects.

CSV to JSON Converter

Convert CSV data into JSON array format instantly.

Api Testing 1

Send REST and SOAP requests and inspect responses.

API Test Lab

Send HTTP requests, inspect responses and copy the code.

Converter 13

Convert between JSON, XML, CSV, query strings and JavaScript objects.

Color Converter (HEX, RGB, HSL)

Convert colors between HEX, RGB and HSL with a live preview.

CSV to JSON Converter

Convert CSV data into JSON array format instantly.

CSV to Markdown Table

Turn CSV or spreadsheet data into a Markdown table.

Javascript Object to JSON

Turn JS objects into valid JSON format online.

Javascript Object to String

Convert JS objects to URL query strings easily.

JSON Stringify

Convert JS objects or arrays into JSON strings online.

JSON to CSV Converter

Convert JSON data into CSV format for Excel or Sheets.

JSON to TypeScript Interface

Generate TypeScript interfaces from a JSON sample.

JSON to XML Converter

Convert structured JSON data into clean XML format.

Markdown to HTML Converter

Convert Markdown to clean HTML.

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal.

Query String to JavaScript Object

Convert URL query strings into JavaScript objects.

XML to JSON Converter

Convert structured XML into JSON format instantly.

Developer 7

Everyday utilities for developers: timestamps, regular expressions and more.

Card Number Validator (Luhn)

Check a card number with the Luhn algorithm and detect its network.

Chmod Calculator

Work out Unix file permissions in octal and symbolic form.

CIDR and Subnet Calculator

Calculate network, broadcast and host range from a CIDR block.

Cron Expression Explainer

Explain a cron schedule and see its next run times.

HTTP Status Codes Reference

Look up any HTTP status code by number or keyword.

Regex Tester

Test regular expressions and see every match and capture group.

Unix Timestamp Converter

Convert Unix timestamps to dates and dates to timestamps.

Difference 1

Compare two JSON documents and see exactly what changed.

JSON Difference Checker

Compare and highlight differences between two JSON objects.

Encoder 7

Encode, decode, hash and inspect data such as Base64, URLs, JWTs and HTML entities.

Base64 Encode and Decode

Encode text to Base64 or decode Base64 back to text.

Hash Generator (SHA-1, SHA-256, SHA-512)

Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text.

HTML Entities Encode and Decode

Escape or unescape HTML special characters and entities.

JSON String Escape and Unescape

Escape text for use inside a JSON string, or unescape it.

JWT Decoder

Decode a JSON Web Token and read its header and payload.

Text to Binary, Hex and Decimal

Convert text to binary, hex, decimal or octal and back.

URL Encode and Decode

Percent-encode or decode URLs and query string values.

Formatter 4

Beautify, validate and minify structured data so it is readable.

CSS Minifier

Minify CSS by removing comments and whitespace.

JSON Formatter

Extension

Beautify and validate JSON data online.

JSON Validator

Check JSON and see exactly where the error is.

XML Formatter

Beautify and validate XML code effortlessly.

Generator 6

Generate UUIDs, passwords and placeholder text instantly.

CSS Gradient Generator

Create CSS gradients with a live preview.

Lorem Ipsum Generator

Generate placeholder text by paragraphs, sentences or words.

Password Generator

Create strong random passwords with the character types you choose.

Random Number Generator

Generate random numbers in a range, with unique and decimal options.

Random String Generator

Generate random strings, tokens and IDs of any length.

UUID Generator (v4)

Generate random version 4 UUIDs in bulk.

Marketing 16

Campaign calculators, A/B test tools, link builders and copy checkers for marketers.

A/B Test Sample Size Calculator

Work out how many visitors each variant needs.

A/B Test Significance Calculator

Check whether your A/B test result is statistically significant.

Add to Calendar Link Generator

Create Google, Outlook and .ics calendar links for an event.

Break-even ROAS Calculator

Find the minimum ROAS and the maximum CPA you can afford.

Bulk UTM Link Builder

Add the same UTM parameters to a whole list of URLs.

Coupon Code Generator

Generate unique, readable promo codes in bulk.

Email Subject Line Checker

Check your subject line for length and spam-style wording.

Hashtag Generator

Turn keywords and phrases into ready-to-use hashtags.

Keyword Density Checker

Find the most used words and phrases in your text.

LTV and CAC Calculator

Estimate customer lifetime value, LTV:CAC ratio and payback time.

Mailto Link Generator

Create a mailto link with subject, body, CC and BCC.

Marketing Metrics Calculator (CTR, CPC, CPA, ROAS)

Calculate CTR, CPM, CPC, CPA, conversion rate, ROAS and ROI.

Readability Checker (Flesch Score)

Score how easy your text is to read.

SERP Title and Description Length Checker

Check title and meta description length for Google results.

Social Media Character Counter

Check your text against X, LinkedIn, Instagram and more.

UPI Payment Link Generator

Create a UPI payment link with amount and note.

Seo 2

Check redirects, preview search results and generate meta tags.

Meta Tag Generator for SEO

Generate SEO-friendly meta tags with customizable title, description, and social previews.

Redirection Checker

Check and trace the redirection path of any URL instantly.

Text Tool 9

Change case, count words, sort lines and create clean slugs.

Email Extractor

Pull every email address out of a block of text.

Find and Replace

Find and replace text, with regular expression support.

HTML Tag Stripper

Remove HTML tags and keep the plain text.

List Converter (Lines and Comma Separated)

Convert lines to a comma separated list and back.

Number to Words Converter

Write numbers in words, in international or Indian format.

Slug Generator

Turn titles into clean, URL-friendly slugs.

Sort and Dedupe Lines

Sort, reverse, deduplicate and clean up lines of text.

Text Case Converter

Convert text to upper, lower, title, camel, snake, kebab case and more.

Word and Character Counter

Count words, characters, sentences and reading time.

Url Tool 8

Break down, edit and shorten URLs and their query parameters.

Domain Extractor

Get the domains and hostnames from a list of URLs.

Punycode Converter (IDN)

Convert internationalized domain names to and from Punycode.

Tracking Parameter Remover

Strip UTM, fbclid, gclid and other tracking parameters from URLs.

URL Extractor

Pull every link out of a block of text.

URL Normalizer

Standardize URLs: lowercase host, sort parameters, remove fragments and slashes.

Url Pro Analyzer

Extension

Analyze, decode, and manipulate URLs like a pro.

UTM Link Builder

Build campaign URLs with UTM parameters for tracking.

WhatsApp Link Generator

Create a wa.me click-to-chat link with a pre-filled message.

Why DevTools

Private by design

Formatting and conversion run in your browser. Your JSON, XML and URLs are not uploaded or stored.

Instant results

No waiting on a server. Paste your input and get the output immediately.

Free, no sign-up

Every tool is free to use with no account, trial or usage limit.

Works anywhere

Use it on desktop, tablet or phone. Nothing to install, and Chrome extensions are available for some tools.

How it works

  1. Pick a tool. Search, or browse by category in the sidebar.
  2. Paste your input. Text, a URL, JSON or XML, depending on the tool.
  3. Copy the result. Output is ready to copy straight into your code, API client or docs.

FAQ

Is my data sent to a server?

For formatters and converters, no. Processing happens locally in your browser. Tools that need the network, such as the redirection checker, only send the requests you ask them to make.

Do I need an account?

No. There is no sign-up and no paywall.

Can I use these tools for work?

Yes. They are free for personal and commercial use.

How do I suggest a new tool or report a bug?

Use the contact page and tell us what you need.