This feature requires MailerPress Pro 2.1.0 or later.
ToSend is an email sending service. Connect it to MailerPress to send your campaigns, automation emails and test emails, and to track bounces (emails returned as undeliverable, for example because the address doesn’t exist).
1. Prepare your ToSend account
- Create an account on the ToSend website or sign in.
- In the ToSend dashboard, add and verify your sending domain. ToSend rejects emails sent from an unverified domain.
- Go to the API Keys section, create an API key for MailerPress and copy it. MailerPress uses this secret key to send through your ToSend account.
2. Link your site with the ToSend API
- Go to MailerPress > Integrations and open the Email Service Providers tab.
- In Other Providers, click Configure on the ToSend card.
- Paste your key in the ToSend API key field.
- Fill in Default sender email address and Default sender name. The address must use your verified ToSend domain. Empty fields show your global default sender as a placeholder.
- Click Save changes. The card moves to Configured Providers.
- Turn on the card’s Enable toggle, then click Set as primary provider. The card shows the Primary badge: only the primary provider sends your emails.
3. Send a test email
- On the ToSend card, open the Actions menu (three dots) and click Send test email.
- Enter a recipient in Send to and click Send.
You should receive an email with the subject “This is a Sending Method Test”. If the test fails, MailerPress shows the error returned by ToSend:
- 401: the API key is missing. Check the ToSend API key field.
- 403: the API key is invalid or your ToSend account has insufficient credits.
- 422: the domain isn’t verified, there are too many recipients, or the content is missing. Verify your domain in the ToSend dashboard.
- 429: too many requests. Wait before trying again.
4. Configure the sending speed
- Go to MailerPress > Settings > Sending frequency, or click Adjust sending frequency on the ToSend card.
- Under Configuration Mode, choose Profile and select one of the ToSend profiles below. You can also choose Automatic to let MailerPress pick a profile, or Manual to set your own values.
- Click Save settings.
| Profile | Emails per batch | Interval | Emails per hour |
|---|---|---|---|
| Prudent (Starter plan) | 50 | 5 minutes | 600 |
| Balanced (Recommended) | 100 | 5 minutes | 1,200 |
| Performance (Pro plans) | 250 | 5 minutes | 3,000 |
The sending frequency is saved for the provider that is primary at that moment. Set ToSend as primary before you click Save settings. See How to change your sending frequency in MailerPress.
5. Enable bounce tracking
MailerPress learns about bounces through a webhook: a URL that ToSend calls automatically when an email bounces.
- On the ToSend card, click Configure.
- Turn on Enable bounce tracking. The setting is saved immediately.
- Under Webhook URL, click Copy. The URL looks like
https://example.com/wp-json/mailerpress/v1/esp/bounce/tosend. - In your ToSend dashboard, create a webhook with this URL and subscribe it to bounce events (
bounced). The Learn how to configure link in MailerPress opens ToSend’s webhook guide. - Add complaint events (
complaint, sent when a recipient marks your email as spam) only if you also want them to mark the contact as bounced. - If ToSend gives you a signing secret for the webhook (a shared password that proves notifications really come from ToSend), paste it in Webhook signing secret and click Save secret.
Once a secret is saved, MailerPress rejects any ToSend notification without a valid signature. Without a secret, MailerPress only records a bounce if it sent an email to that address through ToSend in the last 30 days.
6. Track your bounces
Go to MailerPress > Audience and click the Bounced tab of the contact list. Campaigns only go to subscribed contacts, so bounced contacts no longer receive them.
To compare ToSend with the other sending services, see Choose and configure your email sending service.