> ## Documentation Index
> Fetch the complete documentation index at: https://docs.opentechacademy.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Open Tech Tools: Free Browser-Based Utilities

> Free browser-based utilities at opentechtools.org for converting images, PDFs, and audio locally, plus encrypted file sharing with full client-side privacy.

**Open Tech Tools** (available at [opentechtools.org](https://opentechtools.org)) is a suite of free web-based utility tools built by Open Tech Academy. Every tool runs client-side inside the user's browser, ensuring that files never touch a remote server, offering complete privacy.

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## Design Principles

* **No Paywalls or Ads**: Unlimited, free usage for all users.
* **Privacy First**: Calculations and conversions happen locally on your computer.
* **Zero Server Uploads**: Unlike traditional converters that upload your documents to third-party servers, your data remains in your browser.

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## Available Utilities

### 1. Image Converter

Easily convert images between popular formats:

* **Supported Formats**: PNG, JPEG, WEBP, BMP, and SVG.
* **Features**: Quality compression controls, bulk image resizing, and aspect ratio locks.

### 2. PDF Converter & Editor

Manipulate and edit PDF documents without exposing sensitive information:

* **Features**: Convert images to PDF, merge multiple PDFs, extract individual pages, or split documents by section.

### 3. Audio & Media Converter

Convert audio tracks locally:

* **Supported Formats**: MP3, WAV, OGG, M4A, and WebM.
* **Features**: Bitrate adjustment and audio track trimming.

### 4. Data Converter

Parse and translate data schemas:

* **Supported Translations**: JSON to CSV and CSV to JSON.

### 5. Text Toolkit

Clean, format, and manipulate text:

* **Features**: Uppercase, lowercase, title case, sentence case, trim whitespace, and character/word statistics.

### 6. ZIP Builder

Package multiple files directly in the browser:

* **Features**: Client-side ZIP archive creation using `fflate` with custom levels.

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## Encrypted Sharing

Open Tech Tools provides a secure, end-to-end encrypted file sharing utility.

* **Client-Side Encryption**: Files are encrypted with AES-GCM (256-bit) in the browser using the Web Crypto API before upload.
* **Secure Link Generation**: The decryption key is appended to the URL hash fragment (`#`), which is never sent to the hosting server.
* **Expiration Controls**: Set files to expire after 1 hour, 6 hours, 24 hours, or 7 days.
* **QR Code Sharing**: Instantly generate QR codes for secure mobile downloads.

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## Contributing & Open Source

Open Tech Tools is fully open-source and welcomes community contributions.

### Development Setup

1. Clone the repository: `git clone https://github.com/opentechacademy/opentechtools`
2. Run a local web server (e.g. `npx netlify dev` or any static file server) to load the assets under `public/`.
3. Open `http://localhost:8888` or your local port in your browser.

### Netlify Functions

The E2E encrypted share functionality uses Netlify functions located in `netlify/functions/` to store encrypted file chunks in **Netlify Blobs**. Make sure to configure the appropriate Environment Variables (`LMS_DATABASE_URL` if linking to database systems, or Netlify Blob permissions) when deploying your own instance.