> ## Documentation Index
> Fetch the complete documentation index at: https://docs.prism.byescaleira.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration

> Type-safe configuration from environment variables and .env files.

# Configuration

`PrismConfig` loads settings from environment variables and `.env` files with type-safe accessors. No YAML, no TOML — just key-value pairs with built-in support for environment-specific overrides.

## Loading Configuration

```swift title="Load from .env" theme={null}
let config = PrismConfig.load()
// Reads .env, then .env.{PRISM_ENV} if set
// Environment variables always win over file values
```

```swift title="From Environment Only" theme={null}
let config = PrismConfig.fromEnvironment(overrides: [
    "PORT": "3000",
    "LOG_LEVEL": "debug"
])
```

## .env File Format

```bash title=".env" theme={null}
# Database
DATABASE_URL=sqlite:///data/app.db
DATABASE_POOL_SIZE=5

# Server
PORT=8080
HOST=0.0.0.0

# App
APP_SECRET=my-secret-key
PRISM_ENV=development
```

```bash title=".env.production" theme={null}
PORT=443
PRISM_ENV=production
LOG_LEVEL=warn
```

<Note>
  Environment variables take priority over `.env` file values. This lets you override settings per-deployment without changing files. The `.env.{environment}` file loads after `.env`, letting you layer environment-specific values.
</Note>

## Type-Safe Accessors

```swift title="Reading Values" theme={null}
// Strings
let dbURL = config.get("DATABASE_URL")              // String?
let host = config.get("HOST", default: "0.0.0.0")   // String

// Required values (throws if missing)
let secret = try config.require("APP_SECRET")        // String

// Integers
let poolSize = config.getInt("POOL_SIZE")            // Int?
let port = config.getInt("PORT", default: 8080)      // Int

// Booleans (accepts: true/1/yes, false/0/no)
let debug = config.getBool("DEBUG")                  // Bool?
let verbose = config.getBool("VERBOSE", default: false) // Bool

// Doubles
let timeout = config.getDouble("TIMEOUT")            // Double?
```

## Built-In Properties

```swift title="Convenience Properties" theme={null}
config.environment    // PRISM_ENV or "development"
config.isProduction   // true if PRISM_ENV == "production"
config.isDevelopment  // true if PRISM_ENV == "development"
config.port           // PORT as UInt16, default 8080
config.host           // HOST or "0.0.0.0"
config.keys           // All loaded configuration keys
```

## Practical Example

```swift title="Configure Server from .env" theme={null}
let config = PrismConfig.load()

let server = PrismHTTPServer(port: config.port)

if config.isProduction {
    await server.use(PrismSecurityHeadersMiddleware())
    await server.use(PrismHSTSMiddleware())
}

let db = try PrismDatabase(path: config.get("DATABASE_URL", default: ":memory:"))
let poolSize = config.getInt("POOL_SIZE", default: 5)
let pool = PrismConnectionPool(factory: { try PrismDatabase(path: dbPath) }, maxConnections: poolSize)

print("Starting \(config.environment) server on \(config.host):\(config.port)")
try await server.start()
```

## Error Handling

```swift title="Handle Missing Config" theme={null}
do {
    let secret = try config.require("JWT_SECRET")
    let dbURL = try config.require("DATABASE_URL")
} catch PrismConfigError.missingKey(let key) {
    fatalError("Missing required configuration: \(key)")
}
```

<Tip>
  Keep your `.env` file out of version control (add it to `.gitignore`). Commit a `.env.example` with placeholder values so new developers know which keys to set.
</Tip>

<Warning>
  Never put secrets directly in code. Always load them from environment variables or `.env` files. In production, use your platform's secret management (Docker secrets, Kubernetes ConfigMap, etc.) to inject environment variables.
</Warning>