GESIS Surf

An Open-Source Infrastructure for Privacy-Preserving Longitudinal Web Browsing Data Collection

---

---

Features • Installation • Usage • API Documentation • Contributing • License

---

GESIS Surf is an open-source research infrastructure for privacy-preserving, longitudinal collection of web browsing behavioral data at scale — combining a browser extension, REST API backend, and hierarchical session modeling to enable reproducible passive panel studies created by GESIS – Leibniz Institute for the Social Sciences.

🔗 Looking for the backend? Check out GESIS Surf Backend

✨ Features

• � Passive Longitudinal Data Collection - Captures naturalistic browsing behavior over time without interrupting users, enabling large-scale panel studies
• 🏗️ Hierarchical Session Modeling - Preserves the full structure of browsing behavior across windows, tabs, domains, and interactions
• 📄 Content-Level Capture - Records clicks, scrolls, DOM changes, page metadata, and full HTML snapshots per observation
• 🛡️ Privacy-by-Design - Strict opt-in participation, per-domain collection rules, and client-side data minimization at the point of collection
• 🌐 Cross-Browser Support - Works on both Chrome and Firefox via WebExtension API
• 🔐 Secure Authentication - Token-based authentication with secure session management
• 💾 Client-Side Storage - IndexedDB for local data buffering before transmission
• ♻️ Reproducible Infrastructure - Open-source, self-hostable backend with REST API for transparent and auditable research workflows

📋 Requirements

• Node.js: >= 18.12.0
• Package Manager: pnpm 9.1.1 or higher

🚀 Installation

Clone the repository and install dependencies:

git clone git@github.com:gesiscss/gesis_surf_extension.git
cd gesis_surf_extension
npm install
# or
pnpm install

🔨 Building the Extension

Firefox

Build the extension for Firefox (default):

 pnpm run build:firefox

The compiled files will be in the dist/ directory.

To load the extension in Firefox:

1. Navigate to about:debugging#/runtime/this-firefox
2. Or go to Firefox > Preferences > Extensions & Themes > Debug Add-ons > Load Temporary Add-on...
3. Locate and select the dist/manifest.json file

Chrome

Build the extension for Google Chrome:

pnpm run build

The compiled files will be in the dist/ directory.

To load the extension in Chrome:

1. Open chrome://extensions/
2. Enable Developer mode (top-right corner)
3. Click Load unpacked
4. Select the dist/ directory

💻 Development

Start the Development Server

For Chrome (with HMR support):

pnpm run dev

For Firefox (with HMR support):

pnpm run dev:firefox

Available Scripts

• pnpm run clean - Clean build artifacts and cache
• pnpm run build - Build for Chrome
• pnpm run build:firefox - Build for Firefox
• pnpm run dev - Start development server (Chrome, with HMR)
• pnpm run dev:firefox - Start development server (Firefox, with HMR)
• pnpm run test - Run tests
• pnpm run type-check - Type-check the entire project
• pnpm run lint - Lint all files
• pnpm run lint:fix - Fix linting issues
• pnpm run prettier - Format code with Prettier
• pnpm run docs - Generate TypeDoc documentation

📁 Project Structure

├── chrome-extension/          # Chrome extension source code
│   ├── lib/                   # Core extension logic
│   │   ├── background/        # Service worker/background script
│   │   ├── controllers/       # Core extension controller
│   │   ├── db/                # Database service and configuration
│   │   ├── events/            # Event managers (Tab, Window, Domain, Content)
│   │   ├── handlers/          # Client and shared message handlers
│   │   ├── messages/          # Message interfaces and handlers
│   │   └── services/          # Auth, data collection, session, sync, policy
│   ├── public/                # Static assets (icons, CSS)
│   ├── utils/plugins/         # Vite manifest plugin
│   └── manifest.js            # Extension manifest
├── pages/                     # UI components and pages
│   ├── content/               # Content script (clicks, scrolls, HTML capture)
│   ├── popup/                 # Extension popup (React, MUI, Auth, PrivacyMode)
│   └── utils/                 # Shared page assets and ConnectedPage HOC
├── packages/                  # Shared packages and utilities
│   ├── dev-utils/             # Manifest parser, logger, and dev utilities
│   ├── hmr/                   # Hot module replacement (rollup-based)
│   ├── shared/                # Shared React hooks, storages, HOCs, and services
│   ├── tailwind-config/       # Shared Tailwind CSS configuration
│   └── tsconfig/              # Shared TypeScript configurations
└── docs/                      # Generated TypeDoc documentation

Key Components

• Background Service Worker (lib/background/) - Manages extension lifecycle, coordinates all events and services
• EventManager (lib/events/) - Orchestrates Tab, Window, Domain, and Content event managers
• Content Script (pages/content/) - Injected script capturing clicks, scrolls, and HTML snapshots per page
• Popup UI (pages/popup/) - React interface for user authentication, privacy mode, and settings
• GlobalSessionService (lib/services/globalSession/) - Builds and maintains the hierarchical session model across windows and tabs
• PolicyService (lib/services/policyService/) - Enforces per-domain and per-content collection rules (privacy-by-design)
• AuthService (lib/services/authService/) - Token-based authentication and session management
• DatabaseService (lib/db/) - IndexedDB client-side data buffering before transmission
• DataCollectionService (lib/services/dataCollectionService/) - Aggregates and processes collected interaction data
• SyncService (lib/services/syncService/) - Handles periodic data synchronization to the backend API
• PrivateModeService (lib/services/privateModeService/) - User-controlled privacy mode with timed activation
• MessageHandler (lib/messages/) - Typed message passing between background, content, and popup scripts

🏗️ Architecture

Extension Architecture

The extension follows a modular architecture:

• Background Script (Service Worker) - Manages extension state and coordinates events
• Content Script - Collects user interaction data from web pages
• Popup UI - Provides user authentication and privacy controls
• Message Passing - Secure communication between background, content, and popup scripts
• IndexedDB - Local storage for data persistence

System Integration

┌─────────────────────┐
│  Browser Extension  │
├─────────────────────┤
│ - Content Script    │  Collects: clicks, scrolls, HTML snapshots,
│ - Background Worker │           domains, tab/window events,
│ - Popup UI          │           session hierarchy, host policy
│ - IndexedDB Storage │
└──────────┬──────────┘
           │ HTTPS/Secure
           │ Authentication
           ▼
┌─────────────────────┐
│  Django Backend     │
├─────────────────────┤
│ - REST API          │  Processes: user registration,
│ - Token Auth        │  authentication, data aggregation,
│ - Database          │  analysis & reporting
│ - Celery/Redis      │
│ - Elasticsearch     │
└─────────────────────┘

Data Flow:

1. On startup/install, AuthService validates the stored token against /api/user/me/
2. If authenticated, HostService syncs the domain blocklist/allowlist from /api/host/hosts/
3. GlobalSessionService creates a hierarchical session (global → window → tab → domain) and posts it to /api/session/
4. EventManager starts TabEventManager, WindowEventManager, DomainEventManager, and ContentEventManager
5. Content script captures clicks, scrolls, and HTML snapshots (with meta tags) and sends them via message passing to the background service worker
6. Background worker writes events to IndexedDB via DatabaseService for local buffering
7. Events are flushed to the backend API (/api/clicks/, /api/scrolls/, /api/tab/tabs/, /api/domain/domains/)
8. HeartbeatService runs every 10 seconds to maintain extension liveness state
9. PrivateModeService suspends data collection when the user activates privacy mode

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for detailed information on:

• 🌿 Branching Strategy - dev → main → prod workflow
• 📝 Commit Conventions - Using Commitizen with Conventional Commits
• 🔍 Code Quality - Pre-commit hooks, linting, and formatting
• 🔀 Pull Request Process - Guidelines and review workflow

Quick Start

1. Fork the repository
2. Create a feature branch from dev

   git checkout dev && git pull origin dev
   git checkout -b feature/amazing-feature

3. Install pre-commit hooks

   pnpm install
   pnpm run prepare

4. Commit using Commitizen

   git add .
   pnpm cz

5. Push and open a Pull Request targeting dev

✅ Code Quality

This project uses:

• ESLint - For code linting
• Prettier - For code formatting
• TypeScript - For type safety
• Husky - For pre-commit and commit-msg hooks
• lint-staged - For running linters on staged files
• commitlint - Enforces Conventional Commits format on every commit message

Run quality checks:

pnpm run lint
pnpm run lint:fix
pnpm run type-check
pnpm run prettier

📦 Technology Stack

• UI: React 18, React Router v6, MUI v6 (Material UI), Emotion, Tailwind CSS
• Build Tools: Vite 6, Turbo (monorepo task runner), Rollup (HMR package)
• Language: TypeScript 5.9
• Storage: IndexedDB via idb library
• Browser APIs: WebExtension API with webextension-polyfill
• Unique IDs: uuid v11 for session identifier generation
• Code Quality: ESLint (Airbnb TypeScript config), Prettier, Husky, lint-staged, commitlint
• Commit Tooling: Commitizen (cz-conventional-changelog), commitlint (@commitlint/config-conventional)
• Package Manager: pnpm 9.1.1 (workspace monorepo)

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

Copyright © 2023-2025 GESIS – Leibniz Institute for the Social Sciences

🔗 Backend Integration

The GESIS Surf Extension works in conjunction with the GESIS Surf Backend for data processing and storage.

Related Repositories

• GESIS Surf Backend - Django REST API for data collection, user management, and research analysis
  • Built with Django 4.2 and Python 3.10+
  • PostgreSQL for persistent storage
  • Celery/Redis for async task processing
  • Elasticsearch for fast data retrieval
  • Docker-ready deployment

Data Collection Endpoints

The extension communicates with the backend API for:

Endpoint	Purpose
/api/user/token/	Authentication token generation
/api/user/me/	User profile and data collection status
/api/session/	Global session hierarchy submission
/api/tab/tabs/	Browser tab event tracking
/api/domain/domains/	Domain classification and event tracking
/api/clicks/	Click event submission
/api/scrolls/	Scroll event submission
/api/host/hosts/	Host blocklist/allowlist sync (policy rules)
/api/host/task-result/	Async host sync task polling
/api/selectors/	Dynamic LLM-based CSS selector retrieval
/api/selectors/task-result/	Async selector task polling

👥 Authors

• Mario Ramirez - Lead Research Software Engineer - @geomario @MarioGesis
• Fernando Guzman - Software Architect Consultant - @Fernando
• Dr. Sebastian Stier - Department Director CSS @Seb
• Dr. Frank Mangold - Kommissarischer Teamleiter DDD @Frank

🙏 Acknowledgments

• GESIS - Leibniz Institute for the Social Sciences
• Computational Social Science Department

🔒 Privacy Notice

This extension is designed with privacy in mind. Data collection is:

• Transparent - Users know what data is being collected
• Ethical - Complies with research ethics standards
• Secure - Uses secure authentication and storage mechanisms
• User-Controlled - Includes privacy mode and user controls

For detailed privacy information, please refer to the project's privacy documentation or contact GESIS directly.

📧 Contact

Questions or feedback? Reach out!

• GitHub Issues: Create an issue
• Backend Issues: Backend Repository
• GESIS: https://www.gesis.org/

📝 Citation

If you use this software in your research, please cite:

@article{ramirez2025gesis,
  title = {GESIS Surf Extension},
  author = {Ramirez, Mario and Guzman, Fernando and Stier, Sebastian and Mangold, Frank},
  journal = {SoftwareX},
  volume = {XX},
  pages = {XXXXXX},
  year = {2026},
  publisher = {Elsevier},
  doi = {10.1016/j.softx.2025.xxxxxx}
}

See CITATION.cff for more citation formats.

---

Made with ❤️ at GESIS