# Authentication

Learn how to sign in, sign up, authenticate and resume sessions with the SurrealDB Swift SDK.

SurrealDB supports a number of methods for authenticating users and securing the database. The Swift SDK exposes these through [`signin`](/docs/reference/swift/methods/signin.md), [`signup`](/docs/reference/swift/methods/signup.md), [`authenticate`](/docs/reference/swift/methods/authenticate.md) and [`invalidate`](/docs/reference/swift/methods/invalidate.md).

## Signing in

The `signin` method accepts a credentials enum describing the level you wish to authenticate at.

### Root user

```swift
let tokens = try await client.signin(.root(username: "root", password: "secret"))
```

### Namespace user

```swift
let tokens = try await client.signin(.namespace(
    namespace: "myapp",
    username: "ns_user",
    password: "secret"
))
```

### Database user

```swift
let tokens = try await client.signin(.database(
    namespace: "myapp",
    database: "mydb",
    username: "db_user",
    password: "secret"
))
```

### Record access with variables

```swift
let tokens = try await client.signin(.accessVariables(
    namespace: "myapp",
    database: "mydb",
    access: "account",
    variables: ["email": .string("user@example.com"), "pass": .string("secret")]
))
```

### Bearer token access

```swift
let tokens = try await client.signin(.accessBearer(
    namespace: "myapp",
    database: "mydb",
    access: "account",
    key: "bearer-token-value"
))
```

## Signing up

New record-access users sign up with `signup`:

```swift
let tokens = try await client.signup(.accessRecord(
    namespace: "myapp",
    database: "mydb",
    access: "account",
    variables: ["email": .string("new@example.com"), "pass": .string("secret")]
))
```

## Resuming a session

You can re-authenticate an existing client with a previously issued access token:

```swift
try await client.authenticate(tokens.access)
```

Alternatively, provide a token when constructing the client through a `SessionContext`:

```swift
let client = try SurrealHTTPClient(
    endpoint: "http://localhost:8000",
    session: SessionContext(
        namespace: "myapp",
        database: "mydb",
        accessToken: "existing-jwt"
    )
)
```

## Invalidating a session

To clear the current authentication state:

```swift
try await client.invalidate()
```