Text Tools
Remove Duplicate Lines
Strip repeated lines from multiline text while keeping first-seen order.
Open Remove Duplicate Lines
Explore all tools
Find the utility you need and open it instantly.
Developer Tools
JSON Formatter / Beautifier
Format and beautify JSON instantly with proper indentation.
Open JSON Formatter / Beautifier
Developer Tools
JSON Fixer
Auto-detect and fix common JSON formatting issues in real time.
Open JSON Fixer
Developer Tools
JSON Schema Validator
Validate JSON against a JSON Schema in the browser with clear errors and example templates.
Open JSON Schema Validator
Developer Tools
CSV to JSON Converter
Convert CSV data into structured JSON quickly.
Open CSV to JSON Converter
Developer Tools
JSON to CSV Converter
Convert JSON arrays of objects (or a single object) into CSV.
Open JSON to CSV Converter
Developer Tools
CSV to TSV Converter
Convert comma-separated values (CSV) into tab-separated values (TSV).
Open CSV to TSV Converter
Developer Tools
TSV to CSV Converter
Convert tab-separated values (TSV) into comma-separated values (CSV).
Open TSV to CSV Converter
Developer Tools
JSON to TypeScript Interface Generator
Generate TypeScript interfaces from JSON samples.
Open JSON to TypeScript Interface Generator
Text Tools
Text Diff Checker (Compare Text)
Compare two text blocks and highlight differences.
Open Text Diff Checker (Compare Text)
Text Tools
Remove Extra Spaces / Clean Text
Clean up extra spaces and normalize plain text.
Open Remove Extra Spaces / Clean Text
Text Tools
Case Converter
Convert text into UPPERCASE, lowercase, Title Case, sentence case, camelCase, PascalCase, or snake_case.
Open Case Converter
Text Tools
Slug Generator
Convert titles and phrases into clean URL-friendly slugs.
Open Slug Generator
Text Tools
Word & Character Counter
Count words, characters (with and without spaces), lines, and paragraphs as you type.
Open Word & Character Counter
Text Tools
Text Sorter
Sort lines alphabetically or numerically with optional case sensitivity and duplicate removal.
Open Text Sorter
Text Tools
Find & Replace Text
Find and replace text using plain matching or regular expressions.
Open Find & Replace Text
Text Tools
Lorem Ipsum Generator
Generate placeholder text for design and development.
Open Lorem Ipsum Generator
Developer Tools
Base64 Encoder
Encode plain text to Base64 instantly.
Open Base64 Encoder
Developer Tools
Base64 Decoder
Decode Base64 back to plain text.
Open Base64 Decoder
Developer Tools
URL Encoder
Encode text into URL-safe format instantly.
Open URL Encoder
Developer Tools
URL Decoder
Decode URL encoded strings back to plain text.
Open URL Decoder
Developer Tools
URL Parser & Analyzer
Break down any URL into protocol, domain, path, query params, and hash.
Open URL Parser & Analyzer
Developer Tools
JWT Decoder
Decode JWT header, payload, and signature parts instantly.
Open JWT Decoder
Developer Tools
JWT Encoder
Encode JWT header and payload JSON into a token.
Open JWT Encoder
Developer Tools
Regex Tester
Test regular expressions against sample text with live highlights, match list, and capture groups.
Open Regex Tester
Developer Tools
SHA256 Hash Generator
Generate SHA256 hashes from text instantly in your browser.
Open SHA256 Hash Generator
Developer Tools
MD5 Hash Generator
Generate MD5 hashes from text instantly in your browser.
Open MD5 Hash Generator
Developer Tools
SHA1 Hash Generator
Generate SHA1 hashes from text instantly with a fast client-side hashing engine.
Open SHA1 Hash Generator
Developer Tools
SHA224 Hash Generator
Generate SHA224 hashes from text instantly in your browser.
Open SHA224 Hash Generator
Developer Tools
SHA384 Hash Generator
Generate SHA384 hashes from text instantly with a fast browser-side hashing engine.
Open SHA384 Hash Generator
Developer Tools
SHA512 Hash Generator
Generate SHA512 hashes from text securely in your browser.
Open SHA512 Hash Generator
Developer Tools
SHA3-256 Hash Generator
Generate SHA3-256 hashes from text instantly in your browser.
Open SHA3-256 Hash Generator
Developer Tools
RIPEMD160 Hash Generator
Generate RIPEMD160 hashes from text instantly in your browser.
Open RIPEMD160 Hash Generator
Developer Tools
HMAC Generator
Generate HMAC signatures with Web Crypto and crypto-es using a secret key and payload.
Open HMAC Generator
Security Tools
Strong Password Generator
Generate strong random passwords with customizable character rules.
Open Strong Password Generator
Security Tools
Password Strength Checker
Analyze password strength with scoring, entropy estimate, breach-risk heuristics, and improvement suggestions.
Open Password Strength Checker
Calculators
Percentage Calculator
Calculate percentages, increases, and decreases quickly.
Open Percentage Calculator
Calculators
SIP Calculator
Calculate SIP growth with compound returns over time.
Open SIP Calculator
Calculators
EMI Calculator
Calculate your monthly EMI, total interest, and total loan repayment.
Open EMI Calculator
Developer Tools
UTM Builder
Generate trackable campaign URLs with UTM parameters and ready-to-copy output.
Open UTM Builder
Developer Tools
QR Code Generator
Generate QR codes from text or links and download as PNG, SVG, or JPEG.
Open QR Code Generator
Developer Tools
Barcode Generator
Generate barcodes in multiple formats and export as PNG, SVG, or JPEG.
Open Barcode Generator
Document Tools
PDF to Image Converter
Convert PDF pages to JPG, PNG, or WEBP images directly in your browser. No upload required.
Open PDF to Image Converter
Document Tools
Markdown to PDF
Convert Markdown to PDF with custom CSS styling and Mermaid diagram support.
Open Markdown to PDF
Developer Tools
Cron Schedule Generator
Build cron schedule expressions with an intuitive visual builder.
Open Cron Schedule Generator
Developer Tools
JSON to Dart Model Generator
Generate Dart model classes with fromJson/toJson from JSON samples.
Open JSON to Dart Model Generator
Developer Tools
JSON to Python Pydantic Model Generator
Generate Python Pydantic BaseModel classes from JSON samples.
Open JSON to Python Pydantic Model Generator
Developer Tools
JSON to Kotlin Data Class Generator
Generate Kotlin data classes with null safety and serialization annotations from JSON samples.
Open JSON to Kotlin Data Class Generator
Developer Tools
JSON to Swift Codable Model Generator
Generate Swift Codable structs from JSON samples with CodingKeys support.
Open JSON to Swift Codable Model Generator
Developer Tools
JSON to Go Struct Generator
Generate Go struct definitions with JSON tags from JSON samples.
Open JSON to Go Struct Generator
Developer Tools
JSON to Zod Schema Generator
Generate Zod validation schemas with inferred TypeScript types from JSON samples.
Open JSON to Zod Schema Generator
Developer Tools
JSON to C# Class Generator
Generate C# classes with JSON property attributes from JSON samples.
Open JSON to C# Class Generator
Developer Tools
JSON to Java POJO Generator
Generate Java POJO classes with Jackson annotations from JSON samples.
Open JSON to Java POJO Generator
Developer Tools
HEX ↔ RGB ↔ HSL Converter
Convert colors between HEX, RGB, and HSL formats with a live color preview.
Open HEX ↔ RGB ↔ HSL Converter
Developer Tools
Color Palette Generator
Generate harmonious color palettes from any base color — complementary, analogous, triadic, and more.
Open Color Palette Generator
Developer Tools
Tailwind Palette Generator
Generate Tailwind CSS v4 color shades (50–950) from any base color with a ready-to-copy @theme snippet.
Open Tailwind Palette Generator
Frequently asked questions
Quick answers about using OnlineToolkit.
OnlineToolkit is a collection of free, fast browser utilities for text, developers, security, and everyday calculations. Open a tool, use it immediately, and leave when you are done.
No. The tools are available without signup. Your session stays in the browser for most utilities, so you can start working right away.
Most tools process input locally in your browser. We do not use your pasted text or files for training, and nothing is stored on our servers for typical client-side tools.
You need a network connection the first time you load a page. After that, many tools continue to work with cached assets until you refresh or clear site data.
Yes. OnlineToolkit is free to use. There are no paywalls for the utilities listed in the catalog.
Browse by category from the Categories page, open the full Tools directory, or use the search on the homepage and tools page to filter by name or description.
Use a current version of Chrome, Firefox, Safari, or Edge. Tools rely on modern JavaScript; very old browsers may not work correctly.
Yes. Copy the output from any tool and paste it into another-for example, format JSON, then convert or diff it in a follow-up step.
We ship improvements and new utilities regularly. Each tool page reflects the latest behavior when you load the site.
OnlineToolkit is built for interactive use in the browser. There is no public HTTP API; integrate by linking to the tools you need.
Check that your input matches the expected format-for example valid JSON for a formatter. Error messages usually point to the line or rule that failed.
Some tools keep your latest input in browser local storage for convenience. You can clear inputs anytime, and browser data can be removed from site settings.