Letta

Letta belongs in the database because it tackles a real problem that most agent products still wave past: persistent memory and long-lived state. The official site positions Letta around agents that remember, learn, and improve over time, while the docs and product surfaces make it clear that this is aimed at developers building stateful agent systems rather than one-off chat wrappers. That makes Letta important infrastructure for teams that think agent memory is part of the product, not a novelty feature.

It also deserves inclusion because the commercial surface is public enough to compare, even though it is not a classic SaaS seat ladder. The official pricing page currently centers on Pro at $20/month, Max Lite at $100/month, and Max at $200/month, while also publishing usage-based charges such as $0.10 per active agent per month and $0.00015 per second of tool execution. That mix matters because it tells buyers that Letta is priced more like an agent platform than a simple subscription app.