FastFollow dispatches every approved follow-up through Resend, then ingests delivery, bounce, and engagement events in real time. Reply tracking, suppression handling, and deliverability monitoring are all built in.
~20 minutes — most of it waiting for DNS propagation
Sign up at resend.com if you do not already have an account. From the dashboard, create a new API key scoped to "Sending access" — this is what FastFollow will use to dispatch follow-ups.
Resend requires a verified domain before it will deliver email. From the Resend dashboard, go to Domains → Add Domain and follow the DNS instructions.
In Resend → Webhooks, add an endpoint pointing to FastFollow. This delivers real-time delivery, bounce, and complaint events back to your tenant.
In FastFollow → Integrations → Resend, set a default From address for AI-drafted follow-ups. This must be on your verified domain.
The exact records you'll add to your DNS provider for domain verification
| Type | Host | Value | Purpose |
|---|---|---|---|
| TXT | @ | v=spf1 include:_spf.resend.com ~all | SPF — authorizes Resend to send on behalf of your domain |
| CNAME | resend._domainkey | resend._domainkey.resend.com | DKIM signing key (verifies messages were not tampered in transit) |
| TXT | _dmarc | v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com | DMARC monitoring — upgrade p=none → p=quarantine after you confirm deliverability |
Exact values may vary slightly per domain — always copy from your Resend dashboard, not from this table.
Events Resend pushes to FastFollow and how they affect your data
email.sentResend accepted the message and queued it for delivery.
email.deliveredRecipient mail server confirmed delivery. Updates follow-up status to "delivered".
email.bouncedHard bounce. FastFollow marks the contact as undeliverable and pauses future sends to that address.
email.complainedRecipient marked the message as spam. FastFollow flags the contact and disables future automated sends.
email.openedTracking pixel loaded. Used to compute engagement signals on Opportunity Rooms.
email.clickedTracked link clicked. Boosts engagement score on the related deal.
See the webhooks reference for signature verification details and payload schemas.
Get your AI-drafted follow-ups landing in inboxes, not spam
Brand-new domains start with zero reputation. Send modest volume for the first 2–3 weeks (under 1,000/day), then ramp gradually. FastFollow surfaces a warning in the approval queue if your domain age is under 30 days.
Start with p=none and a rua= reporting address. After 2–4 weeks, if reports show clean authentication, upgrade to p=quarantine.
FastFollow appends a one-click unsubscribe header to every send. Recipients who unsubscribe are added to your suppression list — never re-send to them, even on a new campaign.
Resend will pause sending if your complaint rate exceeds 0.3%. FastFollow shows your rolling 7-day complaint rate on the Integrations dashboard so you can intervene before that happens.
The most common Resend integration errors
domain_not_verifiedAPI returns "The from address is not valid".
Fix: Your sending domain has not finished verifying in Resend. Check the Domains tab — all three SPF/DKIM/DMARC records must show "verified" status. DNS propagation can take up to 24 hours.
rate_limit_exceededBulk sending returns 429s.
Fix: Resend caps free-tier accounts at 100 emails/day and 10 emails/second. FastFollow respects rate limits with exponential backoff, but high-volume tenants should upgrade their Resend plan.
invalid_signatureInbound webhook events return 401 from FastFollow.
Fix: The Resend signing secret stored in FastFollow does not match the webhook signing secret in the Resend dashboard. Regenerate the secret in Resend → Webhooks → Settings and update it in FastFollow → Integrations → Resend.
bounced_recipientFollow-ups to a specific contact silently fail.
Fix: Resend maintains a suppression list for hard-bounced addresses. Check the contact in FastFollow — if they bounced previously, the address must be removed from Resend’s suppression list before sending resumes.