FastAPI MCP LangGraph Template

Read the docs with demo videos here.

• FastAPI MCP LangGraph Template
  • Core Features
    • Technology Stack and Features
    • Planned Features
  • Architecture
    • Inspector
    • Template Setup
    • Reverse Proxy
    • Monitoring and Observability
  • Getting Started
  • Development
    • VSCode Devcontainer
    • Without VSCode Devcontainer
  • Refactored Markdown Files
    • MCP
    • Supabase
  • Debugging

Core Features

is an open protocol that standardizes how apps provide context to LLMs.

• Seamlessly integrates LLM with growing list of community integrations found here
• No LLM provider lock in

for Customizable Agentic Orchestration

• Native streaming for UX in complex Agentic Workflows
• Native persisted chat history and state management

Technology Stack and Features

• for Python backend API
• for Python SQL database interactions (ORM + Validation).
  • Wrapper of
• for Data Validation and Settings Management.
• for DB RBAC
  • Relational DB
  • Vector Store
• Reverse Proxy
• for development and production.

Planned Features

• for LLM Observability and LLM Metrics
• for scraping Metrics
• for visualizing Metrics
• SaaS for JWT authentication
• CI/CD via Github Actions
  • 💵 Deploy live demo to
  • Provision with IaC
  • Push built images to ECR and Dockerhub

Architecture

Inspector

Inspector communicates via SSE protocol with each MCP Server, while each server adheres to MCP specification.

graph LR

  subgraph localhost
    A[Inspector]
    B[DBHub Server]
    C[Youtube Server]
    D[Custom Server]
  end

  subgraph Supabase Cloud
    E[Supabase DB]
  end

  subgraph Google Cloud
    F[Youtube API]
  end

  A<-->|Protocol|B
  A<-->|Protocol|C
  A<-->|Protocol|D
  B<-->E
  C<-->F

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Template Setup

The current template does not connect to all MCP servers. Additionally, the API server communicates with the database using a SQL ORM.

graph LR

  subgraph localhost
    A[API Server]
    B[DBHub Server]
    C[Youtube Server]
    D[Custom Server]
  end

  subgraph Supabase Cloud
    E[Supabase DB]
  end

  A<-->|Protocol|D
  A<-->E

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Reverse Proxy

graph LR
  A[Web Browser]

  subgraph localhost
    B[Nginx Reverse Proxy]
    C[API Server]
  end

  A-->B
  B-->C

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Monitoring and Observability

graph LR

  subgraph localhost
    A[API Server]
  end

  subgraph Grafana Cloud
    B[Grafana]
  end

  subgraph Langfuse Cloud
    C[Langfuse]
  end

  A -->|Metrics & Logs| B
  A -->|Traces & Events| C

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Getting Started

Build community youtube MCP image with:

./community/youtube/build.sh

Tip

Instead of cloning or submoduling the repository locally, then building the image, this script builds the Docker image inside a temporary Docker-in-Docker container. This approach avoids polluting your local environment with throwaway files by cleaning up everything once the container exits.

Then build the other images with:

docker compose -f compose-dev.yaml build

Copy environment file:

cp .env.sample .env

Add your following API keys and value to the respective file: ./envs/backend.env, ./envs/youtube.env and .env.

OPENAI_API_KEY=sk-proj-...
POSTGRES_DSN=postgresql://postgres...
YOUTUBE_API_KEY=...

Set environment variables in shell: (compatible with bash and zsh)

set -a; for env_file in ./envs/*; do source $env_file; done; set +a

Start production containers:

docker compose up -d

Development

First, set environment variables as per above.

VSCode Devcontainer

Warning

Only replace the following if you plan to start debugger for FastAPI server in VSCode.

Replace ./compose-dev.yaml entrypoint to allow debugging FastAPI server:

# ...
  api:
    # ...
    # entrypoint: uv run fastapi run api/main.py --root-path=/api --reload
    # replace above with:
    entrypoint: bash -c "sleep infinity"
    # ...

code --no-sandbox .

Press F1 and type Dev Containers: Rebuild and Reopen in Container to open containerized environment with IntelliSense and Debugger for FastAPI.

Without VSCode Devcontainer

Run development environment with:

docker compose -f compose-dev.yaml up -d

Refactored Markdown Files

The following markdown files provide additional details on other features:

MCP

./docs/mcp.md

Supabase

./docs/supabase.md

Debugging

Sometimes in development, nginx reverse proxy needs to reload its config to route services properly.

docker compose -f compose-dev.yaml exec nginx sh -c "nginx -s reload"