Elgg
A powerful open source social networking engine
Founded
2004
Starting Price
Free
Category
Collaboration
Last updated March 5, 2026
About Elgg
Elgg is an award-winning open-source social networking engine that provides the core components needed to build socially aware web applications. It offers a flexible, plugin-driven architecture with a well-documented API, enabling developers to create anything from university campus networks to enterprise collaboration platforms. With over 1,000 community plugins available, Elgg can be extended and customized to meet virtually any social networking requirement.
Pros & Cons
Pros
- Completely free and open source under the GPL, with no vendor lock-in or licensing costs
- Highly extensible plugin and theme architecture with over 1,000 community-contributed extensions
- Strong built-in security features including CSRF protection, XSS filtering, and modern password hashing
- Full data ownership — self-hosted deployments keep all user data under the organization's control
- Active development community and long track record since 2004, indicating project maturity and stability
Key Features
Well-Documented Core API
A comprehensive and stable API that enables developers to start building social applications quickly and integrate custom functionality with ease.
Plugin Architecture
A flexible system of hooks and events allows developers to extend or override almost any core behavior without modifying the core codebase. Over 1,000 community plugins are available.
Access Control System
Granular content permission controls let users and administrators define exactly who can view or interact with any piece of content on the platform.
Built-In Security
Includes anti-CSRF validation, XSS filters, HMAC signatures, and advanced password hashing using modern cryptographic methods to protect user data.
Flexible Entity System
A generic entity model allows developers to rapidly prototype and deploy new content types such as posts, files, events, or any custom object.
User Profiles and Groups
Native support for user profiles and group communities, enabling community formation and collaborative spaces within the platform.
Pricing
Open Source (Self-Hosted)
Free
- Full source code access on GitHub
- Core social networking engine
- Plugin and theme system
- Community forum support
- Access to 1,000+ community plugins
Best For
University and Academic Networks
Higher education institutions use Elgg to build campus-wide social networks connecting students, faculty, and staff with profiles, groups, and activity feeds.
Enterprise Intranet and Collaboration
Organizations deploy Elgg as an internal collaboration platform where employees can share knowledge, form working groups, and communicate across departments.
Nonprofit and Community Platforms
Nonprofits and NGOs leverage Elgg to build member communities and advocacy networks where data privacy and ownership are critical priorities.
Custom Social Network Development
Developers and agencies use Elgg as a foundation to build bespoke social networking applications for clients, taking advantage of its flexible API and plugin system.
