Sonzai vs Zep
Short answer: Both Sonzai and Zep are hosted memory layers for AI agents. Sonzai unifies memory, personality, mood, relationships, and a knowledge base in one API with native MCP support. Zep focuses on memory with conversation summarization. Choose Sonzai for a complete mind layer. Choose Zep for conversation memory only.
At a glance
| Feature | Sonzai | Zep |
|---|---|---|
| Type | Hosted API + SDKs | Hosted API + SDKs |
| Memory model | Hierarchical tree (facts, episodes, summaries) | Message history with summarization |
| Personality | Big Five (OCEAN) with trait evolution | — |
| Mood / emotion | 4D mood (valence, arousal, tension, affiliation) | — |
| Relationships | Yes | — |
| Knowledge base | Yes (graph search) | Yes |
| MCP support | Native MCP server | — |
| SDKs | TypeScript, Python, Go | TypeScript, Python |
| Memory retrieval p95 | < 200ms | Varies |
| Best for | Complete mind layer | Conversation memory + summaries |
When to choose Sonzai
- →You need personality, mood, and relationships in addition to memory.
- →You want native MCP support for tool-using agents.
- →You're building in Go as well as TypeScript or Python.
- →You want hierarchical memory (facts, episodes, summaries) rather than message-history summarization.
- →You're building AI characters, companions, tutors, or voice agents that need character continuity.
When to choose Zep
- →You only need conversation memory and summarization, nothing else.
- →You don't need personality, mood, or relationship modeling.
- →You're already integrated with Zep and it works for your use case.
What makes Sonzai different
Memory alone makes an agent informed, not believable. To feel real, an agent needs personality continuity (same voice, same values), mood (drifts and recovers), relationships (knows who you are), and knowledge (facts about the world it inhabits). Sonzai bundles all of this into one API; Zep gives you the memory piece.
Sonzai also offers native MCP support, a Go SDK, and a hierarchical memory tree that separates atomic facts, narrative episodes, and rolled-up summaries.
FAQ
What is the difference between Sonzai and Zep?
Both are hosted memory layers. Sonzai adds personality, mood, relationships, knowledge base, and native MCP. Zep focuses on conversation memory and summarization.
Is Sonzai a Zep alternative?
Yes. Sonzai is a Zep alternative for developers who want personality, mood, and relationship tracking on top of memory.
Does Zep have personality and mood?
No. Zep is focused on memory. Sonzai includes Big Five personality, 4D mood, and relationship tracking.
Which has better SDK coverage?
Sonzai has SDKs for TypeScript, Python, and Go. Zep has SDKs for TypeScript and Python.
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