Alternatives to: Disqus

Apache Answer is a flexible, Open Source Q&A platform for teams and communities to share knowledge.

Chirpy is an Open Source, privacy-friendly comment system for building better online communities.

Commento is a fast, lightweight, and easy-to-use comments widget that enhances website engagement and community building.

Cusdis is a lightweight, Open Source, and privacy-respecting comment system.

Isso is a lightweight, self-hostable commenting server, a drop-in replacement for Disqus.

Question2Answer is a free, Open Source, and highly customizable Q&A platform built with PHP and MySQL, offering robust features and extensive plugin support.