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Open-source, self-hostable memory engine for AI agents using a three-layer sentence graph architecture.

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Vektori

Memory that remembers the story, not just the facts.

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Why Vektori

Building agents that actually remember people is harder than it looks:

  • Facts aren't enough. Knowing a user prefers WhatsApp is different from knowing they've asked three times and are getting frustrated. Most systems give you the what, not the why or how it changed.
  • Patterns stay invisible. Spotting that someone's tone has been shifting across sessions requires more than point-in-time retrieval — you need to see the trajectory.
  • Context overhead explodes. Stuffing raw conversation history into every prompt doesn't scale. You need structure, not just storage.

Vektori solves this with a three-layer sentence graph. Agents don't just recall preferences — they understand how things got there.

FACT LAYER (L0)      <- vector search surface. Short, crisp statements.
        |
EPISODE LAYER (L1)   <- patterns auto-discovered via graph traversal.
        |
SENTENCE LAYER (L2)  <- raw conversation. Sequential NEXT edges. The full story.

Three-layer memory graph: Facts → Episodes → Sentences

Search hits Facts, graph discovers Episodes, traces back to source Sentences. SQLite by default — swap to Postgres, Neo4j, Qdrant, or Milvus when you're ready to scale.


Benchmarks

Tested on long-horizon memory benchmarks — hundreds of turns, real user details buried deep in history.

Benchmark Vektori Mem0 Zep Supermemory Letta
LoCoMo 66% 66% 58%† ~70% ~83%
LongMemEval-S 73% 64% 85%

†Zep's self-reported score is 75%; independently re-evaluated at 58%. Scores across systems are not always directly comparable — model choice (GPT-4o vs GPT-4.1-mini vs local) significantly affects results.

We used gemini-2.5-flash-lite because of token cost, better models imporve accuracy a lot. Benchmarks at L1 level

On LoCoMo and longmemEval, the retrieved context contains the answer in 95% of questions — the gap to 66% is a synthesis problem, not a retrieval one. Actively working on closing it, exploring RL.

Still improving — PRs and evals welcome. Run your own: /benchmarks


Install

pip install vektori                      # SQLite + Postgres
pip install 'vektori[neo4j]'             # + Neo4j support
pip install 'vektori[qdrant]'            # + Qdrant support
pip install 'vektori[milvus]'            # + Milvus support
pip install 'vektori[neo4j,qdrant,milvus]'  # all backends

No Docker, no external services. SQLite by default.


30-Second Quickstart

import asyncio
from vektori import Vektori

async def main():
    v = Vektori(
        embedding_model="openai:text-embedding-3-small",
        extraction_model="openai:gpt-4o-mini",
    )

    await v.add(
        messages=[
            {"role": "user", "content": "I only use WhatsApp, please don't email me."},
            {"role": "assistant", "content": "Got it, WhatsApp only."},
            {"role": "user", "content": "My outstanding amount is ₹45,000 and I can pay by Friday."},
        ],
        session_id="call-001",
        user_id="user-123",
    )

    results = await v.search(
        query="How does this user prefer to communicate?",
        user_id="user-123",
        depth="l1",  # facts + episodes
    )

    for fact in results["facts"]:
        print(f"[{fact['score']:.2f}] {fact['text']}")
    for episode in results["episodes"]:
        print(f"episode: {episode['text']}")

    await v.close()

asyncio.run(main())

Output:

[0.94] User prefers WhatsApp communication
[0.81] Outstanding balance of ₹45,000, payment expected Friday
episode: User consistently avoids email — route all comms to WhatsApp

Retrieval Depths

Pick how deep you want to go.

Depth Returns ~Tokens When to use
l0 Facts only 50-200 Fast lookup, agent planning, tool calls
l1 Facts + Episodes + source Sentences 300-800 Default. Full answer with context
l2 Facts + Episodes + Sentences + ±N context window 1000-3000 Trajectory analysis, full story replay
# Just the facts
results = await v.search(query, user_id, depth="l0")

# Facts + episodes (recommended)
results = await v.search(query, user_id, depth="l1")

# Everything, with surrounding conversation context
results = await v.search(query, user_id, depth="l2", context_window=3)

Build an Agent with Memory

Three lines to wire memory into any agent loop:

import asyncio
from openai import AsyncOpenAI
from vektori import Vektori

client = AsyncOpenAI()

async def chat(user_id: str):
    v = Vektori(
        embedding_model="openai:text-embedding-3-small",
        extraction_model="openai:gpt-4o-mini",
    )
    session_id = f"session-{user_id}-001"
    history = []

    print("Chat with memory (type 'quit' to exit)\n")
    while True:
        user_input = input("You: ").strip()
        if user_input.lower() == "quit":
            break

        # 1. Pull relevant memory
        mem = await v.search(query=user_input, user_id=user_id, depth="l1")
        facts = "\n".join(f"- {f['text']}" for f in mem.get("facts", []))
        episodes = "\n".join(f"- {ep['text']}" for ep in mem.get("episodes", []))

        # 2. Inject into system prompt
        system = "You are a helpful assistant with memory.\n"
        if facts:    system += f"\nKnown facts:\n{facts}"
        if episodes: system += f"\nBehavioral episodes:\n{episodes}"

        # 3. Get response
        history.append({"role": "user", "content": user_input})
        resp = await client.chat.completions.create(
            model="gpt-4o-mini",
            messages=[{"role": "system", "content": system}, *history],
        )
        reply = resp.choices[0].message.content
        history.append({"role": "assistant", "content": reply})
        print(f"Assistant: {reply}\n")

        # 4. Store exchange
        await v.add(
            messages=[{"role": "user", "content": user_input},
                      {"role": "assistant", "content": reply}],
            session_id=session_id,
            user_id=user_id,
        )

    await v.close()

asyncio.run(chat("demo-user"))

More examples in /examples:


Storage Backends

# SQLite (default) — zero config, starts instantly
v = Vektori()

# PostgreSQL + pgvector — production scale
v = Vektori(database_url="postgresql://localhost:5432/vektori")

# Neo4j — native graph traversal for Episode layer
v = Vektori(
    storage_backend="neo4j",
    database_url="bolt://localhost:7687",
    embedding_dimension=1024,   # must match your embedding model
)

# Qdrant — dedicated vector DB, cloud-ready
v = Vektori(
    storage_backend="qdrant",
    database_url="http://localhost:6333",
    embedding_dimension=1024,
)

# Qdrant Cloud
v = Vektori(
    storage_backend="qdrant",
    database_url="https://your-cluster.qdrant.io",
    qdrant_api_key="your-api-key",
    embedding_dimension=1024,
)

# Milvus — high-scale vector store with partition-key isolation
v = Vektori(
    storage_backend="milvus",
    database_url="http://localhost:19530",
    embedding_dimension=1024,
)

# Milvus / Zilliz Cloud
v = Vektori(
    storage_backend="milvus",
    database_url="https://your-cluster-endpoint",
    milvus_token="your-api-key-or-token",
    embedding_dimension=1024,
)

# In-memory — tests / CI
v = Vektori(storage_backend="memory")

All backends via Docker:

git clone https://github.com/vektori-ai/vektori
cd vektori
docker compose up -d                 # starts Postgres, Neo4j, Qdrant, and Milvus

# Postgres
DATABASE_URL=postgresql://vektori:vektori@localhost:5432/vektori python examples/quickstart_postgres.py

# Neo4j
VEKTORI_STORAGE_BACKEND=neo4j VEKTORI_DATABASE_URL=bolt://localhost:7687 vektori add "I prefer dark mode" --user-id u1

# Qdrant
VEKTORI_STORAGE_BACKEND=qdrant VEKTORI_DATABASE_URL=http://localhost:6333 vektori add "I prefer dark mode" --user-id u1

# Milvus
VEKTORI_STORAGE_BACKEND=milvus VEKTORI_DATABASE_URL=http://localhost:19530 vektori add "I prefer dark mode" --user-id u1

# Milvus Cloud
MILVUS_TOKEN=your-api-key VEKTORI_STORAGE_BACKEND=milvus VEKTORI_DATABASE_URL=https://your-cluster-endpoint vektori add "I prefer dark mode" --user-id u1

CLI storage flags:

vektori config --storage-backend qdrant --database-url http://localhost:6333
vektori config --storage-backend milvus --database-url http://localhost:19530
vektori add "my note" --user-id u1
vektori search "preferences" --user-id u1

Model Support

Bring whatever model stack you have. Works with 10 providers out of the box.

# OpenAI
v = Vektori(
    embedding_model="openai:text-embedding-3-small",
    extraction_model="openai:gpt-4o-mini",
)

# Azure OpenAI
# Ensure AZURE_OPENAI_ENDPOINT and AZURE_OPENAI_API_KEY are set
# Note: The string after "azure:" must match your specific Azure deployment names
v = Vektori(
    embedding_model="azure:my-embedding-deployment",
    extraction_model="azure:my-gpt-4o-deployment",
)

# GitHub Models (Copilot)
# Requires GITHUB_TOKEN. You can get one by running `./scripts/get_github_token.sh`
v = Vektori(
    embedding_model="github:text-embedding-3-small",
    extraction_model="github:gpt-4o",
)

# Anthropic
v = Vektori(
    embedding_model="anthropic:voyage-3",
    extraction_model="anthropic:claude-haiku-4-5-20251001",
)

# Fully local, no API keys, no internet
v = Vektori(
    embedding_model="ollama:nomic-embed-text",
    extraction_model="ollama:llama3",
)

# Sentence Transformers (local, no Ollama required)
v = Vektori(embedding_model="sentence-transformers:all-MiniLM-L6-v2")

# BGE-M3 — multilingual, 1024-dim, best local embeddings we've found
v = Vektori(embedding_model="bge:BAAI/bge-m3")

# LiteLLM — 100+ providers through one interface
v = Vektori(extraction_model="litellm:groq/llama3-8b-8192")

NVIDIA NIM - GPU-optimized models via NVIDIA NIM.

# NVIDIA embedding models (Matryoshka: 384-2048 dimensions)
v = Vektori(
    embedding_model="nvidia:llama-nemotron-embed-1b-v2",
    embedding_dimension=1024,  # Optional: 384, 512, 768, 1024, or 2048
)

# NVIDIA LLM models (nvidia/ prefix auto-added)
v = Vektori(extraction_model="nvidia:llama-3.3-nemotron-super-49b-v1")

# Third-party models hosted on NVIDIA NIM (use full path)
v = Vektori(extraction_model="nvidia:z-ai/glm5")

Contributing

Vektori is early and there's a lot of ground to cover. If you're building agents that need memory, your real-world feedback is the most valuable thing you can contribute.

git clone https://github.com/vektori-ai/vektori
cd vektori
pip install -e ".[dev]"
pytest tests/unit/

Star History

Star History Chart


License

Apache 2.0. See LICENSE.

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