---
title: 'Environment Variables'
description: 'Configure MCPHub using environment variables'
---

# Environment Variables

MCPHub uses environment variables for configuration. This guide covers all available variables and their usage.

## Core Application Settings

### Server Configuration

| Variable    | Default       | Description                                                   |
| ----------- | ------------- | ------------------------------------------------------------- |
| `PORT`      | `3000`        | Port number for the HTTP server                               |
| `HOST`      | `0.0.0.0`     | Host address to bind the server                               |
| `NODE_ENV`  | `development` | Application environment (`development`, `production`, `test`) |
| `LOG_LEVEL` | `info`        | Logging level (`error`, `warn`, `info`, `debug`)              |

```env
PORT=3000
HOST=0.0.0.0
NODE_ENV=production
LOG_LEVEL=info
```

### Database Configuration

| Variable       | Default     | Description                        |
| -------------- | ----------- | ---------------------------------- |
| `DATABASE_URL` | -           | PostgreSQL connection string       |
| `DB_HOST`      | `localhost` | Database host                      |
| `DB_PORT`      | `5432`      | Database port                      |
| `DB_NAME`      | `mcphub`    | Database name                      |
| `DB_USER`      | `mcphub`    | Database username                  |
| `DB_PASSWORD`  | -           | Database password                  |
| `DB_SSL`       | `false`     | Enable SSL for database connection |
| `DB_POOL_MIN`  | `2`         | Minimum database pool size         |
| `DB_POOL_MAX`  | `10`        | Maximum database pool size         |

```env
# Option 1: Full connection string
DATABASE_URL=postgresql://username:password@localhost:5432/mcphub

# Option 2: Individual components
DB_HOST=localhost
DB_PORT=5432
DB_NAME=mcphub
DB_USER=mcphub
DB_PASSWORD=your-password
DB_SSL=false
```

## Authentication & Security

### JWT Configuration

| Variable                 | Default | Description                                 |
| ------------------------ | ------- | ------------------------------------------- |
| `JWT_SECRET`             | -       | Secret key for JWT token signing (required) |
| `JWT_EXPIRES_IN`         | `24h`   | JWT token expiration time                   |
| `JWT_REFRESH_EXPIRES_IN` | `7d`    | Refresh token expiration time               |
| `JWT_ALGORITHM`          | `HS256` | JWT signing algorithm                       |

```env
JWT_SECRET=your-super-secret-key-change-this-in-production
JWT_EXPIRES_IN=24h
JWT_REFRESH_EXPIRES_IN=7d
```

### Session & Security

| Variable            | Default | Description                     |
| ------------------- | ------- | ------------------------------- |
| `SESSION_SECRET`    | -       | Session encryption secret       |
| `BCRYPT_ROUNDS`     | `12`    | bcrypt hashing rounds           |
| `RATE_LIMIT_WINDOW` | `15`    | Rate limiting window in minutes |
| `RATE_LIMIT_MAX`    | `100`   | Maximum requests per window     |
| `CORS_ORIGIN`       | `*`     | Allowed CORS origins            |

```env
SESSION_SECRET=your-session-secret
BCRYPT_ROUNDS=12
RATE_LIMIT_WINDOW=15
RATE_LIMIT_MAX=100
CORS_ORIGIN=https://your-domain.com,https://admin.your-domain.com
```

## External Services

### OpenAI Configuration

| Variable                 | Default                  | Description                      |
| ------------------------ | ------------------------ | -------------------------------- |
| `OPENAI_API_KEY`         | -                        | OpenAI API key for smart routing |
| `OPENAI_MODEL`           | `gpt-3.5-turbo`          | OpenAI model for embeddings      |
| `OPENAI_EMBEDDING_MODEL` | `text-embedding-ada-002` | Model for vector embeddings      |
| `OPENAI_MAX_TOKENS`      | `1000`                   | Maximum tokens per request       |
| `OPENAI_TEMPERATURE`     | `0.1`                    | Temperature for AI responses     |

```env
OPENAI_API_KEY=sk-your-openai-api-key
OPENAI_MODEL=gpt-3.5-turbo
OPENAI_EMBEDDING_MODEL=text-embedding-ada-002
OPENAI_MAX_TOKENS=1000
OPENAI_TEMPERATURE=0.1
```

### Redis Configuration (Optional)

| Variable         | Default     | Description             |
| ---------------- | ----------- | ----------------------- |
| `REDIS_URL`      | -           | Redis connection string |
| `REDIS_HOST`     | `localhost` | Redis host              |
| `REDIS_PORT`     | `6379`      | Redis port              |
| `REDIS_PASSWORD` | -           | Redis password          |
| `REDIS_DB`       | `0`         | Redis database number   |
| `REDIS_PREFIX`   | `mcphub:`   | Key prefix for Redis    |

```env
# Option 1: Full connection string
REDIS_URL=redis://username:password@localhost:6379/0

# Option 2: Individual components
REDIS_HOST=localhost
REDIS_PORT=6379
REDIS_PASSWORD=your-redis-password
REDIS_DB=0
REDIS_PREFIX=mcphub:
```

## MCP Server Configuration

### Default Settings

| Variable            | Default             | Description                                  |
| ------------------- | ------------------- | -------------------------------------------- |
| `MCP_SETTINGS_FILE` | `mcp_settings.json` | Path to MCP settings file                    |
| `MCP_SERVERS_FILE`  | `servers.json`      | Path to servers configuration                |
| `MCP_TIMEOUT`       | `30000`             | Default timeout for MCP operations (ms)      |
| `MCP_MAX_RETRIES`   | `3`                 | Maximum retry attempts for failed operations |
| `MCP_RESTART_DELAY` | `5000`              | Delay before restarting failed servers (ms)  |

```env
MCP_SETTINGS_FILE=./config/mcp_settings.json
MCP_SERVERS_FILE=./config/servers.json
MCP_TIMEOUT=30000
MCP_MAX_RETRIES=3
MCP_RESTART_DELAY=5000
```

### Smart Routing

| Variable                    | Default | Description                      |
| --------------------------- | ------- | -------------------------------- |
| `SMART_ROUTING_ENABLED`     | `true`  | Enable AI-powered smart routing  |
| `SMART_ROUTING_THRESHOLD`   | `0.7`   | Similarity threshold for routing |
| `SMART_ROUTING_MAX_RESULTS` | `5`     | Maximum tools to return          |
| `VECTOR_CACHE_TTL`          | `3600`  | Vector cache TTL in seconds      |

```env
SMART_ROUTING_ENABLED=true
SMART_ROUTING_THRESHOLD=0.7
SMART_ROUTING_MAX_RESULTS=5
VECTOR_CACHE_TTL=3600
```

## File Storage & Uploads

| Variable             | Default          | Description                         |
| -------------------- | ---------------- | ----------------------------------- |
| `UPLOAD_DIR`         | `./uploads`      | Directory for file uploads          |
| `MAX_FILE_SIZE`      | `10485760`       | Maximum file size in bytes (10MB)   |
| `ALLOWED_FILE_TYPES` | `image/*,text/*` | Allowed MIME types                  |
| `STORAGE_TYPE`       | `local`          | Storage type (`local`, `s3`, `gcs`) |

```env
UPLOAD_DIR=./data/uploads
MAX_FILE_SIZE=10485760
ALLOWED_FILE_TYPES=image/*,text/*,application/json
STORAGE_TYPE=local
```

### S3 Storage (Optional)

| Variable               | Default     | Description        |
| ---------------------- | ----------- | ------------------ |
| `S3_BUCKET`            | -           | S3 bucket name     |
| `S3_REGION`            | `us-east-1` | S3 region          |
| `S3_ACCESS_KEY_ID`     | -           | S3 access key      |
| `S3_SECRET_ACCESS_KEY` | -           | S3 secret key      |
| `S3_ENDPOINT`          | -           | Custom S3 endpoint |

```env
S3_BUCKET=mcphub-uploads
S3_REGION=us-east-1
S3_ACCESS_KEY_ID=your-access-key
S3_SECRET_ACCESS_KEY=your-secret-key
```

## Monitoring & Logging

### Application Monitoring

| Variable                 | Default | Description                   |
| ------------------------ | ------- | ----------------------------- |
| `METRICS_ENABLED`        | `true`  | Enable metrics collection     |
| `METRICS_PORT`           | `9090`  | Port for metrics endpoint     |
| `HEALTH_CHECK_INTERVAL`  | `30000` | Health check interval (ms)    |
| `PERFORMANCE_MONITORING` | `false` | Enable performance monitoring |

```env
METRICS_ENABLED=true
METRICS_PORT=9090
HEALTH_CHECK_INTERVAL=30000
PERFORMANCE_MONITORING=true
```

### Logging Configuration

| Variable           | Default      | Description                             |
| ------------------ | ------------ | --------------------------------------- |
| `LOG_FORMAT`       | `json`       | Log format (`json`, `text`)             |
| `LOG_FILE`         | -            | Log file path (if file logging enabled) |
| `LOG_MAX_SIZE`     | `10m`        | Maximum log file size                   |
| `LOG_MAX_FILES`    | `5`          | Maximum number of log files             |
| `LOG_DATE_PATTERN` | `YYYY-MM-DD` | Date pattern for log rotation           |

```env
LOG_FORMAT=json
LOG_FILE=./logs/mcphub.log
LOG_MAX_SIZE=10m
LOG_MAX_FILES=5
LOG_DATE_PATTERN=YYYY-MM-DD
```

## Development & Debug

| Variable                 | Default | Description                         |
| ------------------------ | ------- | ----------------------------------- |
| `DEBUG`                  | -       | Debug namespaces (e.g., `mcphub:*`) |
| `DEV_TOOLS_ENABLED`      | `false` | Enable development tools            |
| `HOT_RELOAD`             | `true`  | Enable hot reload in development    |
| `MOCK_EXTERNAL_SERVICES` | `false` | Mock external API calls             |

```env
DEBUG=mcphub:*
DEV_TOOLS_ENABLED=true
HOT_RELOAD=true
MOCK_EXTERNAL_SERVICES=false
```

## Production Optimization

| Variable           | Default | Description                            |
| ------------------ | ------- | -------------------------------------- |
| `CLUSTER_MODE`     | `false` | Enable cluster mode                    |
| `WORKER_PROCESSES` | `0`     | Number of worker processes (0 = auto)  |
| `MEMORY_LIMIT`     | -       | Memory limit per process               |
| `CPU_LIMIT`        | -       | CPU limit per process                  |
| `GC_OPTIMIZE`      | `false` | Enable garbage collection optimization |

```env
CLUSTER_MODE=true
WORKER_PROCESSES=4
MEMORY_LIMIT=512M
GC_OPTIMIZE=true
```

## Configuration Examples

### Development Environment

```env
# .env.development
NODE_ENV=development
PORT=3000
LOG_LEVEL=debug

# Database
DATABASE_URL=postgresql://mcphub:password@localhost:5432/mcphub_dev

# Auth
JWT_SECRET=dev-secret-key
JWT_EXPIRES_IN=24h

# OpenAI (optional for development)
# OPENAI_API_KEY=your-dev-key

# Debug
DEBUG=mcphub:*
DEV_TOOLS_ENABLED=true
HOT_RELOAD=true
```

### Production Environment

```env
# .env.production
NODE_ENV=production
PORT=3000
LOG_LEVEL=info
LOG_FORMAT=json

# Database
DATABASE_URL=postgresql://mcphub:secure-password@db.example.com:5432/mcphub
DB_SSL=true
DB_POOL_MAX=20

# Security
JWT_SECRET=your-super-secure-production-secret
SESSION_SECRET=your-session-secret
BCRYPT_ROUNDS=14

# External Services
OPENAI_API_KEY=your-production-openai-key
REDIS_URL=redis://redis.example.com:6379

# Monitoring
METRICS_ENABLED=true
PERFORMANCE_MONITORING=true

# Optimization
CLUSTER_MODE=true
GC_OPTIMIZE=true
```

### Docker Environment

```env
# .env.docker
NODE_ENV=production
HOST=0.0.0.0
PORT=3000

# Use service names for Docker networking
DATABASE_URL=postgresql://mcphub:password@postgres:5432/mcphub
REDIS_URL=redis://redis:6379

# Security
JWT_SECRET_FILE=/run/secrets/jwt_secret
DB_PASSWORD_FILE=/run/secrets/db_password

# File paths in container
MCP_SETTINGS_FILE=/app/mcp_settings.json
UPLOAD_DIR=/app/data/uploads
LOG_FILE=/app/logs/mcphub.log
```

## Environment Variable Loading

MCPHub loads environment variables in the following order:

1. System environment variables
2. `.env.local` (ignored by git)
3. `.env.{NODE_ENV}` (e.g., `.env.production`)
4. `.env`

### Using dotenv-expand

MCPHub supports variable expansion:

```env
BASE_URL=https://api.example.com
API_ENDPOINT=${BASE_URL}/v1
DATABASE_URL=postgresql://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:${DB_PORT}/${DB_NAME}
```

## Security Best Practices

1. **Never commit secrets** to version control
2. **Use strong, unique secrets** for production
3. **Rotate secrets regularly**
4. **Use environment-specific files**
5. **Validate all environment variables** at startup
6. **Use Docker secrets** for container deployments

## Validation

MCPHub validates environment variables at startup. Invalid configurations will prevent the application from starting with helpful error messages.

Required variables for production:

- `JWT_SECRET`
- `DATABASE_URL` or individual DB components
- `OPENAI_API_KEY` (if smart routing is enabled)

This comprehensive environment configuration ensures MCPHub can be properly configured for any deployment scenario.
