Elgg

Elgg is an open-source framework for building social and collaborative web applications, best suited to schools, universities, and organizations that can run and tailor their own software. Its strongest appeal is the control its plugins and access policies provide; choosing it also means taking responsibility for self-hosting.

Overview

Elgg is a foundation for communities such as campus networks, organizational collaboration spaces, and company communication tools—not a ready-made hosted service. Its granular content policies can support private networks and intranets, which makes it relevant when access boundaries matter. In return, teams need to install and maintain the application themselves, including a database and a configured cron job for background work such as notifications and database cleanup.

Key features

• Extensible behavior: Hooks and events let plugins alter or add to much of an application's functionality. More than 1,000 open-source plugins in the community repository offer a substantial starting point, though selecting and combining extensions requires technical judgment.
• Custom presentation: Elgg's view system lets plugins work together on themes. This gives teams latitude to shape the interface rather than accept a fixed presentation.
• Private spaces, groups, and files: Granular access policies support controlled content, while user groups and a file storage API give plugins ways to organize communities and handle user-generated files.
• Integrations and notifications: RPC web services support connections to external applications and mobile clients. On-site and email notifications are included, and the notification service can support third-party integrations.
• Security mechanisms: Elgg includes anti-CSRF validation, strict XSS filters, HMAC signatures, and password hashing using current cryptographic approaches. These are useful safeguards, but they do not remove the operator's responsibility for securing and maintaining a self-hosted deployment.

Pricing

Elgg is free to download, install, and use. The free option is the whole product model rather than a time-limited trial, so there is no software license charge to begin building a community.

There are two license choices with a meaningful difference: the full framework and core plugins are offered under GPLv2, while the framework without plugins is offered under MIT. The MIT release excludes the mod directory, which contains Elgg's plugins; teams choosing it should not assume they are also receiving the core plugins. Elgg does not list a paid plan, but self-hosting still entails operating the server and required database and cron job.

Platforms

Elgg is available for web applications, self-hosted installations, and API use. Its installation guide recommends Composer as the simplest way to install and maintain a project, with a pre-packaged ZIP file also available. Third-party hosting providers are listed, but the project does not officially endorse them.

Who it's for

Elgg is a strong fit for universities, schools, organizations, and companies that need a tailored social network or collaboration platform and have the technical capacity to operate it. Documentation, tutorials, an API reference, community discussions, technical support forums, and professional service providers give builders several routes to guidance. It is less suitable for teams that need a managed, turnkey community and do not want responsibility for installation and upkeep.

Pros and cons

• Pro: Broad customization. Plugins can change much of the application's behavior and presentation, with a large community repository to draw from.
• Pro: Fine-grained privacy. Granular content policies make private networks and intranets a plausible use case.
• Pro: No license fee. The software is free to install and use, with GPLv2 and framework-only MIT licensing options.
• Con: Self-hosting is part of the deal. A database and configured cron job are required, so teams must be prepared to manage the underlying installation.
• Con: The MIT option omits plugins. Teams wanting the core plugins need to account for the GPLv2 full package rather than treating the MIT release as equivalent.

Alternatives

For a different approach, consider these options:

• NodeBB is worth comparing if a freemium platform with a free plan and a Starter tier at $20 a month is a better fit.
• HumHub offers a self-hosted Community Edition under an AGPLv3 open-source license, with module marketplace access and community support.
• BuddyBoss Platform has a free WordPress community platform, with Platform Pro at $99 a year for updates and support.
• Geneva is a free option for readers seeking group chats and community features on web and mobile.
• BuddyPress is a free, open-source WordPress plugin for self-hosted installations.
• Discourse is another self-hosted open-source choice, with a free plan that includes unlimited members, 2 staff seats, and 500k monthly page views.
• ProfileGrid offers a free Core plan with 90+ core features and free extensions, plus a Premium plan at $79 a month.
• Oxwall is another free option for web and self-hosted communities, with mobile platforms also supported.

Verdict

Choose Elgg if your school, organization, or company wants a configurable social application with private-content controls and can take on self-hosting. Its main reason to choose is the freedom to shape behavior and presentation without a license fee; look elsewhere if you need a managed service or want a complete MIT-licensed package that includes the plugins.