Supabase is an open-source Firebase alternative built on PostgreSQL, offering greater developer control and SQL database accessibility. | Firebase is a mature, comprehensive BaaS tightly integrated with Google, featuring a NoSQL database and extensive tooling, ideal for rapid prototyping. | Database choice (SQL vs. NoSQL) is a primary consideration; Supabase uses PostgreSQL, while Firebase uses Cloud Firestore.
Notion's limitations (offline access, performance with large datasets, limited customization) are driving the search for alternatives. | Alternatives specialize in note-taking (Obsidian, Craft), document collaboration (Coda, Slite), project management (ClickUp, Monday), and knowledge management (Tettra, Outline). | Consider trade-offs between feature richness, learning curve, and price when selecting an alternative.