FAQ

Does go-notification require an ORM?

No. The library uses database/sql directly. No GORM, no Bun, no Ent. You can use an ORM in the rest of your app — the database channel won't interfere because it owns its own table and SQL.

Can I use multiple email drivers at the same time?

Yes. Register them with different names and reference the one you want in Via():

notifier.RegisterChannel("mail-transactional", sendgrid.New(...))
notifier.RegisterChannel("mail-marketing",     mailgun.New(...))

func (n OrderShipped) Via(u notification.Notifiable) []string {
    return []string{"mail-transactional"}
}

Same pattern works for any channel family — two WhatsApp providers with different ban tolerance, two Slack workspaces, two database shards, etc.

Is WAHA safe to use?

WAHA uses an unofficial WhatsApp protocol and carries a real risk of number ban. It's widely used (6k+ GitHub stars) but not sanctioned by Meta. For production where account loss would be catastrophic, use Twilio WhatsApp or Meta Cloud API instead.

We cover the tradeoff in detail on the WhatsApp Overview page.

Does SMTP work on GCP / AWS / DigitalOcean?

Port 25 is blocked on most cloud providers. Port 587 usually works but not always. We recommend API-based email drivers (Mailgun, SendGrid, SES, Resend, Postmark) for any cloud deployment. Full details: SMTP Port Blocking on Cloud.

Can I add my own custom channel?

Yes. Implement the Channel interface and register it like any built-in driver:

type MyChannel struct{}

func (c *MyChannel) Send(ctx context.Context, n notification.Notification, u notification.Notifiable) error {
    // your send logic
    return nil
}

notifier.RegisterChannel("mine", &MyChannel{})

A full walkthrough will land in the Custom Channel guide — coming after Phase 1.

Does it support notification preferences (user opt-out)?

Not as a first-class feature. For now, handle opt-outs inside Via():

func (n OrderShipped) Via(u notification.Notifiable) []string {
    channels := []string{"database"} // always in-app
    user := u.(User)
    if user.WantsEmail    { channels = append(channels, "mail") }
    if user.WantsWhatsApp { channels = append(channels, "whatsapp") }
    return channels
}

First-class preferences (per-type, per-channel opt-out, digest batching) are planned for post-1.0.

How does retry work?

Failed sends are retried with exponential backoff:

• 1st retry after 1s
• 2nd retry after 2s
• 3rd retry after 4s

Configurable via MaxRetries and RetryDelay in notification.Config. If all retries fail, the registered OnError callback fires with the final error.

What happens if one channel fails but others succeed?

Each channel is independent. If whatsapp fails but mail succeeds, only WhatsApp is retried. OnError is called per-channel-failure, not per-notification.

Does Send() block?

No — it returns immediately. Dispatch happens on the worker pool. If you need synchronous behavior (for example, in a CLI tool), set Config.Async = false.

How do I test notifications without sending real messages?

• For email: register Mailtrap as your mail channel. Messages go to a sandbox inbox.
• For everything else: implement a test channel that captures calls, register it under the same name as production, and assert on it.

Where is the changelog?

Here. Every release documents breaking changes, new drivers, and bug fixes.