> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://www.comet.com/docs/opik/contributing/guides/local-development/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://www.comet.com/_mcp/server.

# Local Development Setup

> Comprehensive guide for setting up and running Opik locally for development

This guide provides detailed instructions for setting up your local Opik development environment. We offer multiple development modes optimized for different workflows.

## Quick Start

Choose the approach that best fits your development needs:

| Development Mode       | Use Case                                  | Command                                   | Speed  |
| ---------------------- | ----------------------------------------- | ----------------------------------------- | ------ |
| **Docker Mode**        | Testing full stack, closest to production | `./opik.sh --build`                       | Slow   |
| **Local Process Mode** | Fast BE + FE development                  | `scripts/dev-runner.sh`                   | Fast   |
| **BE-Only Mode**       | Backend development only                  | `scripts/dev-runner.sh --be-only-restart` | Fast   |
| **Infrastructure**     | Manual with IDE development               | `./opik.sh --infra --port-mapping`        | Medium |

> **Tip**
>
> **Working with multiple branches?** Opik supports [multi-worktree development](#multi-worktree-support) - run multiple environments simultaneously with automatic port isolation.

## Prerequisites

### Required Tools

* **Docker** and **Docker Compose** - For running infrastructure services
* **Java 25** and **Maven** - For backend development
* **Node.js 18+** and **npm** - For frontend development
* **Python 3.10+** and **pip** - For SDK development

### Verify Installation

```bash
# Check Docker
docker --version
docker compose version

# Check Java and Maven
java -version
mvn -version

# Check Node.js and npm
node --version
npm --version

# Check Python
python --version
```

## Development Modes

### 1. Docker Mode (Full Stack)

**Best for**: Testing complete system, integration testing, or when you need an environment closest to production.

#### How It Works

The `opik.sh` script manages Docker Compose profiles to start different combinations of services:

* Infrastructure: MySQL, ClickHouse, Redis, MinIO, ZooKeeper
* Backend: Java backend application
* Frontend: React application
* Optional: Guardrails service

#### Starting Opik in Docker

```bash
# Build and start all services (recommended for first time)
./opik.sh --build

# Start without rebuilding (if no code changes)
./opik.sh

# Enable port mapping (useful for debugging)
./opik.sh --build --port-mapping

# Enable debug logging
./opik.sh --build --debug
```

#### Available Profiles

```bash
# Infrastructure only (MySQL, Redis, ClickHouse, ZooKeeper, MinIO)
./opik.sh --infra --port-mapping

# Infrastructure + Backend services
./opik.sh --backend --port-mapping

# All services EXCEPT backend (for local backend development)
./opik.sh --local-be --port-mapping

# Add guardrails services
./opik.sh --build --guardrails
```

#### Managing Docker Services

```bash
# Check service health
./opik.sh --verify

# View system status
./opik.sh --info

# Stop all services and clean up
./opik.sh --stop

# Rebuild specific service
docker compose -f deployment/docker-compose/docker-compose.yaml build backend
```

#### Accessing Services

* **UI**: [http://localhost:5173](http://localhost:5173)
* **Backend API**: [http://localhost:8080](http://localhost:8080)
* **MySQL**: localhost:3306
* **ClickHouse**: localhost:8123
* **Redis**: localhost:6379

### 2. Local Process Mode (Fast Development)

**Best for**: Rapid backend and frontend development with instant code reloading.

#### How It Works

The `dev-runner.sh` script:

1. Starts infrastructure services in Docker (MySQL, Redis, ClickHouse, etc.)
2. Builds backend and runs it as a local process
3. Runs frontend with Vite dev server as a local process
4. Runs database migrations automatically

#### Starting Development Environment

```bash
# Full restart (stop, build, start) - DEFAULT
scripts/dev-runner.sh

# Or explicitly
scripts/dev-runner.sh --restart

# Start without rebuilding (faster if no dependency changes)
scripts/dev-runner.sh --start

# Stop all services
scripts/dev-runner.sh --stop

# Check status
scripts/dev-runner.sh --verify

# View logs
scripts/dev-runner.sh --logs
```

#### Debug Mode

```bash
# Enable verbose logging
scripts/dev-runner.sh --restart --debug

# Or set environment variable
DEBUG_MODE=true scripts/dev-runner.sh --restart
```

#### Service Details

**Backend Process**:

* Port: 8080 (default, may vary with [multi-worktree support](#multi-worktree-support))
* Logs: `/tmp/opik-<worktree-id>-backend.log`
* PID file: `/tmp/opik-<worktree-id>-backend.pid`
* CORS enabled for local frontend
* Auto-built from `apps/opik-backend`

**Frontend Process**:

* Port: 5174 (default, may vary with [multi-worktree support](#multi-worktree-support))
* Logs: `/tmp/opik-<worktree-id>-frontend.log`
* PID file: `/tmp/opik-<worktree-id>-frontend.pid`
* Hot-reload enabled
* Proxies API calls to backend

**Infrastructure (Docker)**:

* Same services as Docker mode
* Ports mapped for local access (may be offset with multi-worktree support)

> **Tip**
>
> Port assignments are shown when the environment starts. With multi-worktree support, ports may be offset from the defaults.

#### Accessing Services

* **UI**: [http://localhost:5174](http://localhost:5174) (local Vite dev server, port may vary)
* **Backend API**: [http://localhost:8080](http://localhost:8080) (port may vary)
* **Infrastructure**: Same ports as Docker mode (may be offset)

#### SDK Configuration

After starting, configure the SDK to use your local instance:

```bash
opik configure --use_local
```

**IMPORTANT**: You must manually edit `~/.opik.config` to remove `/api` from the URL:

```ini
[opik]
# Change from:
url_override = http://localhost:8080/api/

# To:
url_override = http://localhost:8080
workspace = default
```

Or use environment variables:

```bash
export OPIK_URL_OVERRIDE='http://localhost:8080'
export OPIK_WORKSPACE='default'
```

> **Note**
>
> If using [multi-worktree support](#multi-worktree-support), replace `8080` with your actual backend port (shown when the environment starts).

### 3. BE-Only Mode (Backend Development)

**Best for**: Backend-focused development when you don't need to modify frontend code.

#### How It Works

This mode:

1. Starts infrastructure services in Docker
2. Starts frontend in Docker (pre-built)
3. Runs backend as a local process with hot-reload

The frontend in Docker proxies API calls to your local backend process.

#### Starting BE-Only Mode

```bash
# Full restart (stop, build backend, start)
scripts/dev-runner.sh --be-only-restart

# Start without rebuilding
scripts/dev-runner.sh --be-only-start

# Stop services
scripts/dev-runner.sh --be-only-stop

# Check status
scripts/dev-runner.sh --be-only-verify
```

#### Service Details

**Backend Process** (Local):

* Port: 8080
* Logs: `/tmp/opik-backend.log`
* Auto-built and hot-reloadable

**Frontend** (Docker):

* Port: 5173 (Docker container)
* Pre-built image
* Proxies to localhost:8080

**Infrastructure** (Docker):

* All infrastructure services

#### Accessing Services

* **UI**: [http://localhost:5173](http://localhost:5173) (Docker frontend)
* **Backend API**: [http://localhost:8080](http://localhost:8080) (local process)

#### SDK Configuration

Configure SDK without the manual edit requirement:

```bash
opik configure --use_local
# Use URL: http://localhost:5173
```

Or with environment variables:

```bash
export OPIK_URL_OVERRIDE='http://localhost:5173/api'
export OPIK_WORKSPACE='default'
```

### 4. Infrastructure Only Mode

**Best for**: SDK development, integration testing, or when you need just the databases.

```bash
# Start only infrastructure services
./opik.sh --infra --port-mapping

# Verify infrastructure is running
./opik.sh --infra --verify

# Stop infrastructure
./opik.sh --infra --stop
```

This gives you access to:

* MySQL on port 3306
* ClickHouse on port 8123
* Redis on port 6379
* MinIO on port 9000

## Multi-Worktree Support

Opik supports running multiple development environments simultaneously from different git worktrees. This is useful when you need to work on multiple features or compare branches side-by-side.

### How It Works

Each worktree automatically gets:

1. **Unique port assignments** - All services use offset ports to avoid conflicts
2. **Isolated Docker containers** - Separate container namespaces per worktree
3. **Separate log and PID files** - No interference between worktrees

The port offset (0-99) is deterministically calculated from an MD5 hash of your project path, ensuring consistent port assignments across restarts.

### Port Assignments

| Service           | Base Port | With Offset (e.g., 42) |
| ----------------- | --------- | ---------------------- |
| Backend           | 8080      | 8122                   |
| Frontend          | 5174      | 5216                   |
| MySQL             | 3306      | 3348                   |
| Redis             | 6379      | 6421                   |
| ClickHouse HTTP   | 8123      | 8165                   |
| ClickHouse Native | 9000      | 9042                   |
| Python Backend    | 8000      | 8042                   |
| Zookeeper         | 2181      | 2223                   |
| MinIO API         | 9001      | 9043                   |
| MinIO Console     | 9090      | 9132                   |

### Running Multiple Worktrees

```bash
# Terminal 1: Main branch
cd ~/opik
scripts/dev-runner.sh --restart
# Access at ports based on hash of ~/opik

# Terminal 2: Feature branch
cd ~/opik-worktrees/feature-xyz
scripts/dev-runner.sh --restart
# Access at different ports based on hash of ~/opik-worktrees/feature-xyz
```

### Manual Port Override

If you need specific ports (e.g., to use standard ports or avoid conflicts):

```bash
# Use standard ports (offset 0)
OPIK_PORT_OFFSET=0 scripts/dev-runner.sh --restart

# Use a specific offset
OPIK_PORT_OFFSET=10 scripts/dev-runner.sh --restart
```

### Port Collision Detection

The script automatically checks for port conflicts before starting:

```bash
# If ports are in use, you'll see:
[ERROR] Port 8122 (Backend) is already in use

Port collision detected! Another process is using one or more required ports.
This might be caused by:
  - Another Opik instance running from a different worktree
  - Stale containers from a previous run
  - Other services using the same ports

To resolve:
  1. Stop other Opik instances: ./scripts/dev-runner.sh --stop
  2. Use a different port offset: export OPIK_PORT_OFFSET=<0-99>
  3. Check running processes: lsof -i :8122
```

### Docker Container Naming

Containers are prefixed with the worktree project name:

* Main repo: `opik-opik-mysql-1`, `opik-opik-backend-1`
* Worktree: `opik-feature-xyz-mysql-1`, `opik-feature-xyz-backend-1`

### SDK Configuration for Worktrees

Configure the SDK to use your worktree's backend port (shown when the environment starts):

```bash
# Configure SDK (use the backend port shown at startup)
export OPIK_URL_OVERRIDE='http://localhost:8080'  # or your worktree's port
export OPIK_WORKSPACE='default'
```

Or edit `~/.opik.config`:

```ini
[opik]
url_override = http://localhost:8122
workspace = default
```

## Windows Development

All scripts have PowerShell equivalents for Windows developers.

### Docker Mode (Windows)

```powershell
# Build and start all services
.\opik.ps1 --build

# Different profiles
.\opik.ps1 --infra --port-mapping
.\opik.ps1 --backend --port-mapping
.\opik.ps1 --local-be --port-mapping

# Manage services
.\opik.ps1 --verify
.\opik.ps1 --stop
```

### Local Process Mode (Windows)

```powershell
# Full restart
scripts\dev-runner.ps1

# Specific commands
scripts\dev-runner.ps1 --restart
scripts\dev-runner.ps1 --start
scripts\dev-runner.ps1 --stop
scripts\dev-runner.ps1 --verify

# BE-only mode
scripts\dev-runner.ps1 --be-only-restart

# Debug mode
scripts\dev-runner.ps1 --restart --debug
```

#### Windows-Specific Notes

* Logs location: `$env:TEMP` directory
* PID files: `$env:TEMP` directory
* Use `Get-Content -Wait` instead of `tail -f` for log following
* Configuration file: `$env:USERPROFILE\.opik.config`

## Common Development Tasks

### Building Components

```bash
# Build backend only
scripts/dev-runner.sh --build-be

# Build frontend only
scripts/dev-runner.sh --build-fe

# Lint backend
scripts/dev-runner.sh --lint-be

# Lint frontend
scripts/dev-runner.sh --lint-fe
```

### Database Migrations

```bash
# Run migrations only
scripts/dev-runner.sh --migrate

# This will:
# 1. Start infrastructure if not running
# 2. Build backend if needed
# 3. Run MySQL migrations
# 4. Run ClickHouse migrations
```

If migrations fail, you may need to clean up:

```bash
# Stop all services
scripts/dev-runner.sh --stop  # or ./opik.sh --stop

# Remove Opik Docker volumes (WARNING: DATA LOSS - removes Opik databases)
./opik.sh --clean

# Restart
scripts/dev-runner.sh --restart
```

### Viewing Logs

```bash
# Show recent logs (last 20 lines)
scripts/dev-runner.sh --logs

# Follow logs in real-time
tail -f /tmp/opik-backend.log
tail -f /tmp/opik-frontend.log

# On Windows
Get-Content -Wait $env:TEMP\opik-backend.log
Get-Content -Wait $env:TEMP\opik-frontend.log
```

### Working with Docker Services

```bash
# View all Opik containers
docker ps --filter "name=opik-"

# View logs from Docker services
docker logs -f opik-backend-1
docker logs -f opik-frontend-1
docker logs -f opik-clickhouse-1

# Execute commands in containers
docker exec -it opik-mysql-1 mysql -u root -p
docker exec -it opik-clickhouse-1 clickhouse-client

# Restart a specific Docker service
docker restart opik-backend-1
```

## Troubleshooting

### Services Won't Start

```bash
# Check Docker is running
docker info

# Check port conflicts (ports shown when environment starts)
lsof -i :5174  # Frontend (default)
lsof -i :8080  # Backend (default)
lsof -i :3306  # MySQL (default)
lsof -i :8123  # ClickHouse (default)

# On Windows
Get-NetTCPConnection -LocalPort 5174
Get-NetTCPConnection -LocalPort 8080
```

> **Tip**
>
> If you have port conflicts from another worktree, you can override the port offset:
>
> ```bash
> OPIK_PORT_OFFSET=0 scripts/dev-runner.sh --restart
> ```

### Build Failures

```bash
# Clean backend build
cd apps/opik-backend
mvn clean
mvn spotless:apply  # Fix formatting issues
mvn clean install

# Clean frontend build
cd apps/opik-frontend
rm -rf node_modules
npm install
npm run lint
```

### Database Connection Issues

```bash
# Check MySQL is accessible
docker exec -it opik-mysql-1 mysql -u root -p

# Check ClickHouse is accessible
docker exec -it opik-clickhouse-1 clickhouse-client

# Or via HTTP
echo 'SELECT version()' | curl -H 'X-ClickHouse-User: opik' -H 'X-ClickHouse-Key: opik' 'http://localhost:8123/' -d @-
```

### Process Management Issues

```bash
# Kill stuck backend process
pkill -f "opik-backend.*jar"

# Kill stuck frontend process
pkill -f "vite.*opik-frontend"

# On Windows
Get-Process | Where-Object {$_.Path -like "*opik-backend*"} | Stop-Process -Force
Get-Process | Where-Object {$_.Path -like "*opik-frontend*"} | Stop-Process -Force
```

### Clean Slate Restart

```bash
# Complete cleanup and restart
scripts/dev-runner.sh --stop
./opik.sh --clean  # WARNING: Deletes Opik data
scripts/dev-runner.sh --restart
```

## Development Workflow Examples

### Backend Feature Development

```bash
# 1. Start BE-only mode (fastest for backend work)
scripts/dev-runner.sh --be-only-restart

# 2. Make changes in apps/opik-backend

# 3. Rebuild and restart backend
scripts/dev-runner.sh --build-be
scripts/dev-runner.sh --be-only-start

# 4. Test changes via UI at http://localhost:5173
```

### Frontend Feature Development

```bash
# 1. Start local process mode
scripts/dev-runner.sh --restart

# 2. Make changes in apps/opik-frontend
# Frontend hot-reloads automatically

# 3. View changes at http://localhost:5174
```

### Full Stack Feature Development

```bash
# 1. Start local process mode
scripts/dev-runner.sh --restart

# 2. Make changes to backend and frontend
# Frontend changes hot-reload
# Backend changes require rebuild:

scripts/dev-runner.sh --build-be
# Backend automatically restarts

# 3. Test at http://localhost:5174
```

### SDK Development

```bash
# 1. Start infrastructure only
./opik.sh --infra --port-mapping

# 2. Start backend separately if needed
cd apps/opik-backend
mvn clean install
java -jar target/opik-backend-*.jar server config.yml

# 3. Configure SDK
opik configure --use_local

# 4. Test SDK changes
cd sdks/python
pip install -e .
pytest tests/e2e
```

### Integration Testing

```bash
# 1. Start full Docker stack
./opik.sh --build

# 2. Run tests against full environment
cd tests_end_to_end
pytest tests/

# 3. Clean up
./opik.sh --stop
```

## Performance Tips

1. **Use local process mode** for fastest development cycle
2. **Use BE-only mode** if you're not changing frontend
3. **Use `--start` instead of `--restart`** when dependencies haven't changed
4. **Enable debug mode only when needed** - it increases log verbosity
5. **Keep Docker images up to date** - rebuild periodically with `--build`

## Best Practices

1. **Always run linters before committing**:
   ```bash
   scripts/dev-runner.sh --lint-be
   scripts/dev-runner.sh --lint-fe
   ```

2. **Test migrations locally** before committing:
   ```bash
   scripts/dev-runner.sh --migrate
   ```

3. **Clean up regularly** to free disk space:
   ```bash
   # Clean up Opik Docker resources (WARNING: DATA LOSS - removes Opik databases)
   ./opik.sh --clean  # Removes Opik containers and volumes

   # Or clean up dangling Docker containers, networks, images (affects all projects)
   docker system prune
   ```

4. **Use debug mode for troubleshooting**:
   ```bash
   scripts/dev-runner.sh --restart --debug
   ```

5. **Check service status before reporting issues**:
   ```bash
   scripts/dev-runner.sh --verify
   ./opik.sh --verify
   ```

## IDE Configuration

Opik provides AI coding rules and configurations for editors like Cursor, Codex, and Claude Code. These are stored in `.agents/` and can be synced to your editor of choice using Makefile.

### Setup

```bash
# For Cursor users - creates .cursor symlink to .agents/
make cursor

# For Codex users - creates .codex symlink and generates Codex-compatible AGENTS files
make codex

# For Claude Code users - syncs rules to .claude/ and generates .mcp.json
make claude
```

`make codex` keeps `.codex` linked to `.agents` and generates `AGENTS.override.md` plus `.agents/generated/codex/rules/*.md` so Codex can consume rule content derived from `.mdc` files.

### Directory Structure

```
.agents/
├── rules/                    # AI coding rules (.mdc files)
│   ├── *.mdc                 # Root-level rules (git, clean-code, etc.)
│   ├── apps/                 # App-specific rules
│   │   ├── opik-backend/     # Java backend rules
│   │   └── opik-frontend/    # React frontend rules
│   └── sdks/                 # SDK-specific rules
├── commands/                 # Slash commands
└── mcp.json                  # MCP server configuration
```

### Git Hooks

Install pre-commit hooks to automatically run linting before commits:

```bash
# Install hooks
make hooks

# Remove hooks
make hooks-remove
```

## Next Steps

* [Backend Development Guide](/docs/opik/contributing/guides/backend) - Deep dive into backend development
* [Frontend Development Guide](/docs/opik/contributing/guides/frontend) - Deep dive into frontend development
* [Python SDK Development Guide](/docs/opik/contributing/guides/python-sdk) - SDK contribution guidelines
* [Testing Guide](overview.mdx#testing) - Running and writing tests

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