About
About this site
Mr. Tools is a site that collects practical tools you can use directly in your browser for image conversion, text formatting, developer support, and network checks.
We collect the small tasks you often need in daily work and provide them in a form you can use immediately in the browser without installation or sign-up.
- Prioritize clear and easy-to-use UI
- Keep processing in the browser whenever possible
- Continue improving based on requests and issue reports
- Launched
- April 16, 2026
- Available tools
- 15 tools
- Supported languages
- Japanese, English, 中文, Español
Site operator
- Operator
- Individual (based in Japan)
- Purpose
- Providing free, practical tools that work entirely in the browser
- Contact
- Please use the contact page to get in touch
Published tools
Image Background Removal
Remove image backgrounds in the browser and save the result as a PNG.
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Image Format Conversion
Convert PNG, JPEG, WebP, BMP, GIF, AVIF, HEIC, and SVG directly in the browser.
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Image Crop & Resize
Crop images, adjust dimensions, and save the result directly.
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Video Format Conversion
Convert videos to MP4, WebM, MOV, or GIF and save them directly.
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Base64 Encode / Decode
Convert text to Base64 or restore Base64 text back to readable text.
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URL Encode / Decode
URL-encode or decode text and query parameter values directly in the browser.
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JSON Formatter
Format broken JSON and check syntax errors immediately.
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HTML / CSS / JS Formatter
Format and minify HTML, CSS, and JavaScript, then copy the result directly.
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IP & Network Information Checker
Check global IP, connection status, browser, screen size, and device information in one place.
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Markdown Preview
Edit Markdown and preview it with themes in split view or fullscreen.
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Mermaid Preview
Type Mermaid syntax and preview flowcharts or sequence diagrams in the browser.
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PlantUML Preview
Write PlantUML syntax and review UML diagrams in the browser.
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Color Picker, Image, and Transparency Support
Pick a color, convert HEX, RGB, and HSL values, and copy them directly.
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Favicon Generator
Create favicon.ico, PNG icons, SVG favicon, and a manifest from an image or a simple logo.
Open tool page
QR Code Generator
Create QR codes from URLs or text and save them as PNG or SVG.
Open tool page
Categories
Image Tools
A set of image tools for everyday work, including conversion, compression, and cropping.
View categoryVideo Tools
A set of video tools for browser-friendly tasks such as format conversion and lightweight adjustments.
View categoryText Tools
Browser-based tools for notes, Markdown, and common encoding or text transformations.
View categoryDeveloper Tools
Utilities for frequent developer workflows such as JSON, Mermaid, and Base64 handling.
View categoryDesign Tools
Utilities for design work such as color picking, color conversion, and quick palette checks.
View categoryGenerator Tools
Create deliverables such as QR codes and favicons directly in the browser.
View category