---
title: Mailer Bridge
description: Transactional email delivery for verification, password resets, magic links, and invitations.
---

The Mailer bridge provides transactional email delivery for all Authsome email notifications: email address verification, password reset links, magic link sign-in, and organisation invitations. You provide the mailer implementation; Authsome provides the message content.

If you need multi-channel delivery (email + SMS + push) or template management, use the [Herald bridge](/docs/authsome/bridges/herald) instead — Herald supersedes both the Mailer and SMS bridges when configured.

## Interface

The `bridge.Mailer` interface is defined in `github.com/xraph/authsome/bridge`:

```go
type Mailer interface {
    SendEmail(ctx context.Context, msg *EmailMessage) error
}

type EmailMessage struct {
    To      []string `json:"to"`
    From    string   `json:"from,omitempty"` // Falls back to configured default sender
    Subject string   `json:"subject"`
    HTML    string   `json:"html,omitempty"`
    Text    string   `json:"text,omitempty"` // Plain-text fallback
}
```

## Setup with a Resend adapter

```go
import (
    "github.com/xraph/authsome"
    "github.com/xraph/authsome/bridge/maileradapter"
)

eng, err := authsome.New(
    authsome.WithStore(pgStore),
    authsome.WithPlugin(password.New()),
    authsome.WithMailer(maileradapter.NewResend(os.Getenv("RESEND_API_KEY"),
        maileradapter.WithFromAddress("noreply@myapp.com"),
        maileradapter.WithFromName("My App"),
    )),
)
```

## Setup with a SendGrid adapter

```go
import "github.com/xraph/authsome/bridge/maileradapter"

eng, err := authsome.New(
    authsome.WithStore(pgStore),
    authsome.WithMailer(maileradapter.NewSendGrid(os.Getenv("SENDGRID_API_KEY"),
        maileradapter.WithFromAddress("noreply@myapp.com"),
    )),
)
```

## Setup with an SMTP adapter

```go
import "github.com/xraph/authsome/bridge/maileradapter"

eng, err := authsome.New(
    authsome.WithStore(pgStore),
    authsome.WithMailer(maileradapter.NewSMTP(maileradapter.SMTPConfig{
        Host:     "smtp.example.com",
        Port:     587,
        Username: os.Getenv("SMTP_USERNAME"),
        Password: os.Getenv("SMTP_PASSWORD"),
        From:     "noreply@myapp.com",
        TLS:      true,
    })),
)
```

## Custom implementation

Implement `bridge.Mailer` directly for any email provider:

```go
type PostmarkMailer struct {
    client *postmark.Client
    from   string
}

func (m *PostmarkMailer) SendEmail(ctx context.Context, msg *bridge.EmailMessage) error {
    _, err := m.client.SendEmail(postmark.Email{
        From:     m.from,
        To:       strings.Join(msg.To, ","),
        Subject:  msg.Subject,
        HTMLBody: msg.HTML,
        TextBody: msg.Text,
    })
    return err
}

eng, err := authsome.New(
    authsome.WithStore(pgStore),
    authsome.WithMailer(&PostmarkMailer{
        client: postmark.NewClient(os.Getenv("POSTMARK_TOKEN"), ""),
        from:   "noreply@myapp.com",
    }),
)
```

## Emails sent by Authsome

| Email | Trigger | Subject |
|-------|---------|---------|
| Email verification | User signs up | "Verify your email address" |
| Password reset | User requests reset | "Reset your password" |
| Magic link | User requests magic link sign-in | "Sign in to [App Name]" |
| Organisation invitation | Admin invites member | "You've been invited to [Org Name]" |
| Welcome email | User completes registration | "Welcome to [App Name]" |

The subject lines and HTML/text body content are generated by Authsome's built-in templates. If you want fully customised email content and templates, use the [Herald bridge](/docs/authsome/bridges/herald) which provides a full template management system.

## Standalone development stub

During development, use the built-in `NoopMailer` that logs all outgoing emails at debug level:

```go
import (
    "log/slog"
    "github.com/xraph/authsome/bridge"
)

eng, err := authsome.New(
    authsome.WithStore(memory.New()),
    authsome.WithMailer(bridge.NewNoopMailer(slog.Default())),
)
```

Log output:

```
DEBUG authsome mailer (noop) to=user@example.com subject=Verify your email address
```

<Callout type="info">
When no Mailer bridge is configured (and no Herald bridge either), Authsome's password and magic link plugins will still function but will not send email. Users will not receive verification emails, password reset links, or magic links. Always configure a mailer in production.
</Callout>