* fix(logs): persist execution diagnostics markers Store last-started and last-completed block markers with finalization metadata so later read surfaces can explain how a run ended without reconstructing executor state. * fix(executor): preserve durable diagnostics ordering Await only the persistence needed to keep diagnostics durable before terminal completion while keeping callback failures from changing execution behavior. * fix(logs): preserve fallback diagnostics semantics Keep successful fallback output and accumulated cost intact while tightening progress-write draining and deduplicating trace span counting for diagnostics helpers. * fix(api): restore async execute route test mock Add the missing AuthType export to the hybrid auth mock so the async execution route test exercises the 202 queueing path instead of crashing with a 500 in CI. * fix(executor): align async block error handling * fix(logs): tighten marker ordering scope Allow same-millisecond marker writes to replace prior markers and drop the unused diagnostics read helper so this PR stays focused on persistence rather than unread foundation code. * fix(logs): remove unused finalization type guard Drop the unused helper so this PR only ships the persistence-side status types it actually uses. * fix(executor): await subflow diagnostics callbacks Ensure empty-subflow and subflow-error lifecycle callbacks participate in progress-write draining before terminal finalization while still swallowing callback failures. --------- Co-authored-by: test <test@example.com> Co-authored-by: Vikhyath Mondreti <vikhyath@simstudio.ai>
The open-source platform to build AI agents and run your agentic workforce. Connect 1,000+ integrations and LLMs to orchestrate agentic workflows.
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
npx simstudio
Note
Docker must be installed and running on your machine.
Options
| Flag | Description |
|---|---|
-p, --port <port> |
Port to run Sim on (default 3000) |
--no-pull |
Skip pulling latest Docker images |
Self-hosted: Docker Compose
git clone https://github.com/simstudioai/sim.git && cd sim
docker compose -f docker-compose.prod.yml up -d
Using Local Models with Ollama
Run Sim with local AI models using Ollama - no external APIs required:
# 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:
docker compose -f docker-compose.ollama.yml exec ollama ollama pull llama3.1:8b
Using an External Ollama Instance
If Ollama is running on your host machine, use host.docker.internal instead of localhost:
OLLAMA_URL=http://host.docker.internal:11434 docker compose -f docker-compose.prod.yml up -d
On Linux, use your host's IP address or add extra_hosts: ["host.docker.internal:host-gateway"] to the compose file.
Using vLLM
Sim supports vLLM for self-hosted models. Set VLLM_BASE_URL and optionally VLLM_API_KEY in your environment.
Self-hosted: Dev Containers
- Open VS Code with the Remote - Containers extension
- Open the project and click "Reopen in Container" when prompted
- Run
bun run dev:fullin the terminal or use thesim-startalias- This starts both the main application and the realtime socket server
Self-hosted: Manual Setup
Requirements: Bun, Node.js v20+, PostgreSQL 12+ with pgvector
- Clone and install:
git clone https://github.com/simstudioai/sim.git
cd sim
bun install
- Set up PostgreSQL with pgvector:
docker run --name simstudio-db -e POSTGRES_PASSWORD=your_password -e POSTGRES_DB=simstudio -p 5432:5432 -d pgvector/pgvector:pg17
Or install manually via the pgvector guide.
- Configure environment:
cp apps/sim/.env.example apps/sim/.env
cp packages/db/.env.example packages/db/.env
# Edit both .env files to set DATABASE_URL="postgresql://postgres:your_password@localhost:5432/simstudio"
- Run migrations:
cd packages/db && bunx drizzle-kit migrate --config=./drizzle.config.ts
- Start development servers:
bun run dev:full # Starts both Next.js app and realtime socket server
Or run separately: bun run dev (Next.js) and cd apps/sim && bun run dev:sockets (realtime).
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_KEYenvironment variable in your self-hosted apps/sim/.env file to that value
Environment Variables
Key environment variables for self-hosted deployments. See .env.example for defaults or env.ts for the full list.
| Variable | Required | Description |
|---|---|---|
DATABASE_URL |
Yes | PostgreSQL connection string with pgvector |
BETTER_AUTH_SECRET |
Yes | Auth secret (openssl rand -hex 32) |
BETTER_AUTH_URL |
Yes | Your app URL (e.g., http://localhost:3000) |
NEXT_PUBLIC_APP_URL |
Yes | Public app URL (same as above) |
ENCRYPTION_KEY |
Yes | Encrypts environment variables (openssl rand -hex 32) |
INTERNAL_API_SECRET |
Yes | Encrypts internal API routes (openssl rand -hex 32) |
API_ENCRYPTION_KEY |
Yes | Encrypts API keys (openssl rand -hex 32) |
COPILOT_API_KEY |
No | API key from sim.ai for Copilot features |
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


