go-notification

Mailtrap has two products:

Email Testing (Sandbox) — catches outgoing email in a fake inbox so you can inspect what your app sends without emailing real users.
Email Sending — a production transactional sending service, like Mailgun/SendGrid.

The go-notification driver supports both. Most teams register the sandbox inbox for dev/staging and the production sender for prod, using different env vars.

Pricing

Sandbox — free for up to 100 emails captured/month; paid tiers add more inboxes and higher volumes.
Sending — from $15/month for 10,000 emails.

Exact tiers: https://mailtrap.io/pricing.

Setup (Sandbox for testing)

Create an inbox at https://mailtrap.io → Email Testing.
Copy the API credentials: Inbox ID and API Token.

main.go

import "github.com/gopackx/go-notification/channel/mail/mailtrap"

notifier.RegisterChannel("mail", mailtrap.New(mailtrap.Config{
    Mode:    mailtrap.ModeSandbox,
    APIKey:  os.Getenv("MAILTRAP_API_TOKEN"),
    InboxID: "1234567",
    From:    "noreply@example.com",
}))

Setup (Production sending)

In Email Sending, add and verify your domain.
Create an API key.

main.go

notifier.RegisterChannel("mail", mailtrap.New(mailtrap.Config{
    Mode:   mailtrap.ModeProduction,
    APIKey: os.Getenv("MAILTRAP_API_TOKEN"),
    From:   "noreply@example.com",
}))

Configuration reference

Field	Type	Required	Description
`Mode`	`Mode`	yes	`ModeSandbox` or `ModeProduction`.
`APIKey`	`string`	yes	Mailtrap API token.
`InboxID`	`string`	sandbox	Required in sandbox mode. Ignored in production.
`From`	`string`	yes	Sender address. In sandbox, anything works; in prod, must be verified.
`FromName`	`string`	no	Display name.
`Timeout`	`time.Duration`	no	HTTP timeout per send. Default: `30s`.

Dev → staging → prod pattern

main.go

mode := mailtrap.ModeSandbox
if os.Getenv("APP_ENV") == "production" {
    mode = mailtrap.ModeProduction
}

notifier.RegisterChannel("mail", mailtrap.New(mailtrap.Config{
    Mode:   mode,
    APIKey: os.Getenv("MAILTRAP_API_TOKEN"),
    // InboxID only used in sandbox mode
    InboxID: os.Getenv("MAILTRAP_INBOX_ID"),
    From:    "noreply@example.com",
}))

Troubleshooting

401 on sandbox — wrong API token OR the token is for a different Mailtrap product (sending vs testing). Check the token's scope in the dashboard.
Emails don't appear in sandbox inbox — wrong InboxID, or mode is set to production.
Production send rejected — domain not verified or account still in trial.