simstudioai/sim

Build and deploy AI agent workflows in minutes.

Build Workflows with Ease

Design agent workflows visually on a canvas—connect agents, tools, and blocks, then run them instantly.

Supercharge with Copilot

Leverage Copilot to generate nodes, fix errors, and iterate on flows directly from natural language.

Integrate Vector Databases

Upload documents to a vector store and let agents answer questions grounded in your specific content.

Quickstart

Cloud-hosted: sim.ai

Self-hosted: NPM Package

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npx simstudio

→ http://localhost:3000

Note

Docker must be installed and running on your machine.

Options

Self-hosted: Docker Compose

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# Clone the repository
git clone https://github.com/simstudioai/sim.git

# Navigate to the project directory
cd sim

# Start Sim
docker compose -f docker-compose.prod.yml up -d

Access the application at http://localhost:3000/

Using Local Models with Ollama

Run Sim with local AI models using Ollama - no external APIs required:

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# Start with GPU support (automatically downloads gemma3:4b model)
docker compose -f docker-compose.ollama.yml --profile setup up -d

# For CPU-only systems:
docker compose -f docker-compose.ollama.yml --profile cpu --profile setup up -d

Wait for the model to download, then visit http://localhost:3000. Add more models with:

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docker compose -f docker-compose.ollama.yml exec ollama ollama pull llama3.1:8b

Using an External Ollama Instance

If you already have Ollama running on your host machine (outside Docker), you need to configure the OLLAMA_URL to use host.docker.internal instead of localhost:

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# Docker Desktop (macOS/Windows)
OLLAMA_URL=http://host.docker.internal:11434 docker compose -f docker-compose.prod.yml up -d

# Linux (add extra_hosts or use host IP)
docker compose -f docker-compose.prod.yml up -d  # Then set OLLAMA_URL to your host's IP

Why? When running inside Docker, localhost refers to the container itself, not your host machine. host.docker.internal is a special DNS name that resolves to the host.

For Linux users, you can either:

• Use your host machine’s actual IP address (e.g., http://192.168.1.100:11434)
• Add extra_hosts: ["host.docker.internal:host-gateway"] to the simstudio service in your compose file

Using vLLM

Sim also supports vLLM for self-hosted models with OpenAI-compatible API:

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# Set these environment variables
VLLM_BASE_URL=http://your-vllm-server:8000
VLLM_API_KEY=your_optional_api_key  # Only if your vLLM instance requires auth

When running with Docker, use host.docker.internal if vLLM is on your host machine (same as Ollama above).

Self-hosted: Dev Containers

1. Open VS Code with the Remote - Containers extension
2. Open the project and click “Reopen in Container” when prompted
3. Run bun run dev:full in the terminal or use the sim-start alias
   • This starts both the main application and the realtime socket server

Self-hosted: Manual Setup

Requirements:

• Bun runtime
• Node.js v20+ (required for sandboxed code execution)
• PostgreSQL 12+ with pgvector extension (required for AI embeddings)

Note: Sim uses vector embeddings for AI features like knowledge bases and semantic search, which requires the pgvector PostgreSQL extension.

1. Clone and install dependencies:

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git clone https://github.com/simstudioai/sim.git
cd sim
bun install

2. Set up PostgreSQL with pgvector:

You need PostgreSQL with the vector extension for embedding support. Choose one option:

Option A: Using Docker (Recommended)

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# Start PostgreSQL with pgvector extension
docker run --name simstudio-db \
  -e POSTGRES_PASSWORD=your_password \
  -e POSTGRES_DB=simstudio \
  -p 5432:5432 -d \
  pgvector/pgvector:pg17

Option B: Manual Installation

• Install PostgreSQL 12+ and the pgvector extension
• See pgvector installation guide

3. Set up environment:

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cd apps/sim
cp .env.example .env  # Configure with required variables (DATABASE_URL, BETTER_AUTH_SECRET, BETTER_AUTH_URL)

Update your .env file with the database URL:

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DATABASE_URL="postgresql://postgres:your_password@localhost:5432/simstudio"

4. Set up the database:

First, configure the database package environment:

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cd packages/db
cp .env.example .env 

Update your packages/db/.env file with the database URL:

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DATABASE_URL="postgresql://postgres:your_password@localhost:5432/simstudio"

Then run the migrations:

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cd apps/sim # Required so drizzle picks correct .env file
bunx drizzle-kit migrate --config=./drizzle.config.ts

5. Start the development servers:

Recommended approach - run both servers together (from project root):

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bun run dev:full

This starts both the main Next.js application and the realtime socket server required for full functionality.

Alternative - run servers separately:

Next.js app (from project root):

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bun run dev

Realtime socket server (from apps/sim directory in a separate terminal):

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cd apps/sim
bun run dev:sockets

Copilot API Keys

Copilot is a Sim-managed service. To use Copilot on a self-hosted instance:

• Go to https://sim.ai → Settings → Copilot and generate a Copilot API key
• Set COPILOT_API_KEY environment variable in your self-hosted apps/sim/.env file to that value

Environment Variables

Key environment variables for self-hosted deployments (see apps/sim/.env.example for full list):

Troubleshooting

Ollama models not showing in dropdown (Docker)

If you’re running Ollama on your host machine and Sim in Docker, change OLLAMA_URL from localhost to host.docker.internal:

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OLLAMA_URL=http://host.docker.internal:11434 docker compose -f docker-compose.prod.yml up -d

See Using an External Ollama Instance for details.

Database connection issues

Ensure PostgreSQL has the pgvector extension installed. When using Docker, wait for the database to be healthy before running migrations.

Port conflicts

If ports 3000, 3002, or 5432 are in use, configure alternatives:

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# Custom ports
NEXT_PUBLIC_APP_URL=http://localhost:3100 POSTGRES_PORT=5433 docker compose up -d

Tech Stack

• Framework: Next.js (App Router)
• Runtime: Bun
• Database: PostgreSQL with Drizzle ORM
• Authentication: Better Auth
• UI: Shadcn, Tailwind CSS
• State Management: Zustand
• Flow Editor: ReactFlow
• Docs: Fumadocs
• Monorepo: Turborepo
• Realtime: Socket.io
• Background Jobs: Trigger.dev
• Remote Code Execution: E2B

Contributing

We welcome contributions! Please see our Contributing Guide for details.

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

Made with ❤️ by the Sim Team