# Open-source stack

<div align="left" dir="ltr" id="bkmrk-layer-recommended-op"><table><colgroup><col width="311"></col><col width="311"></col></colgroup><tbody><tr><td>### Layer

</td><td>### Recommended Options

</td></tr><tr><td>LLMs

</td><td>LLaMA 4, Qwen 3, Mixtral, DeepSeek

</td></tr><tr><td>Fast Inference

</td><td>Groq, vLLM, Ollama

</td></tr><tr><td>Agent Framework

</td><td>LlamaIndex

</td></tr><tr><td>Workflow Engine

</td><td>LlamaIndex Workflows

</td></tr><tr><td>API Layer

</td><td>FastAPI

</td></tr><tr><td>Vector DB

</td><td>Qdrant, Chroma

</td></tr><tr><td>Graph DB

</td><td>Neo4j, Memgraph

</td></tr><tr><td>SQL DB

</td><td>PostgreSQL

</td></tr><tr><td>Policy Engine

</td><td>OPA (Open Policy Agent) / Cedar

</td></tr><tr><td>Observability

</td><td>Langfuse / OpenTelemetry

</td></tr><tr><td>Queueing

</td><td>Redis / Kafka

</td></tr><tr><td>Automation

</td><td>N8N

</td></tr><tr><td>Auth

</td><td>OAuth2 / Keycloak

</td></tr><tr><td>Tool interoperability

</td><td>MCP (Model Context Protocol) — now under the Agentic AI Foundation / Linux Foundation

</td></tr><tr><td>Agent memory

</td><td>Mem0, Zep, or a self-hosted tiered store (working / episodic / semantic)

</td></tr></tbody></table>

</div>NEW IN 2026

Anthropic donated MCP to the newly formed Agentic AI Foundation under the Linux Foundation in December 2025, with OpenAI and Block as co-founders and AWS, Google, Microsoft, Cloudflare, GitHub, and Bloomberg as supporting members. It is now a vendor-neutral standard rather than a single-vendor protocol, which is why it belongs in the stack table above rather than only in the tool layer section.