AI agents thatbuild relationships.

Sonzai is the managed relationship layer for consumer AI agents. Persistent memory, personality, mood, and model-agnostic orchestration for AI companions, characters, avatars, and NPCs — through one API.

Book a free call →Build with the SDK →
Guide
The relationship layer

The model knows the world. The agent knows your user.

Per-user memory

Every user gets a private, persistent memory the agent reads on every turn.

Learn more →
Relationship state

Memory, personality, mood, and relationship arc, carried across every session.

Shared world

Multiple characters or NPCs can share canon, lore, and context — without losing per-user state.

Learn more →
01

Persistent memory

Your agent remembers each user across every session — preferences, history, boundaries, and the moments that mattered.

Learn more →
02

Personality & mood

A consistent voice, a current emotional state, and a relationship arc that evolves with the user — not a fresh chatbot every time.

Learn more →
03

Compounding personalization

Every conversation makes the agent more personal. Retention compounds because the user can't get this relationship anywhere else.

Learn more →
Build it yourself, or with us

Forward-deployed engineers wire Sonzai into your product.

Self-build with the SDK, or bring in our engineers to integrate the relational harness directly into your codebase — memory, personality, mood, relationship logic, model routing. We've shipped relational AI surfaces for consumer apps and $70M+ in AI value at DBS Bank. Typical first integration: 4–6 weeks.

Book a free call →Send a written brief →
Forward-deployed loop
Scope the agentWire it into your productOperate the runtime

A relationship that gets more personal every session.

Sonzai turns every conversation into durable relationship state. The agent doesn't just remember more. It feels more consistent, more emotionally coherent, more like someone who actually knows the user.

01

Extract what matters

Every detail the user shares becomes typed memory — preferences, history, boundaries, emotional context.

Learn more →
02

Hold the relationship

Memory, mood, personality, and relationship arc resolve into one coherent user state.

Learn more →
03

Ground the next turn

The agent gets only the context that matters for this user, this moment, this conversation.

Learn more →
04

Grow more personal

Every interaction compounds. The agent becomes more useful — and more impossible to replace.

Learn more →

A live relationship graph under the agent.

The runtime keeps the messy human picture coherent: memories, personality traits, current mood, relationship history, and what changed since the last conversation.

Sources
Conversations, events, tools
State
Memory, mood, personality, arc
Output
One coherent user picture
Next turn
Personal context, not guesswork
Relationship Layer

Every turn updates who this user is to the agent.

Sonzai keeps memory, mood, personality, and relationship arc in sync — so the next answer feels like it's coming from someone who knows them.
Conversation

What the user said, asked, felt, corrected

Personality

Voice, traits, boundaries, how the agent feels

Mood

Current emotional state, energy, valence

Memory

Preferences, history, milestones, inside jokes

Relationship arc

Stage, trust, intimacy, what comes next

Relational AI, answered

Honest answers for teams building consumer AI companions, characters, avatars, and NPCs — and the engineers wiring them up.

Sonzai is the relationship layer for consumer AI agents — a managed platform that gives AI companions, characters, avatars, and NPCs persistent memory, personality, mood, relationship state, and model-agnostic orchestration through one API. Build with our SDK, or bring in our forward-deployed engineers to integrate the relational harness directly into your product.

Read docs →/Talk to us →