Resend at Avo

Resend is the transactional email provider for the Avo platform and for client SaaS projects that need reliable delivery. The Avo site itself sends 14 template types through Resend: welcome, trial started, trial day 1, trial ending, daily brief, weekly metrics, anomaly alert, cold email sequence (three-part), winback sequence (days 4, 7, 14), and customer health alert.

Templates are built with React Email and compiled to HTML at build time. Each template is a typed TypeScript function that accepts explicit props rather than a generic data object. This catches missing required fields at compile time rather than at send time. The template audit run in April 2026 found 13 of 14 templates passing all checks, with one requiring a physical address for CAN-SPAM compliance.

Example workflow: shipping a complete transactional email system for a new SaaS client. 1. Add the domain to Resend and configure SPF, DKIM, and DMARC DNS records before writing any template code. Deliverability setup takes 24 to 48 hours to propagate; do it first. 2. Create an emails/ directory in the Next.js project. Write each template as a TypeScript React Email component with explicit typed props (e.g., WelcomeEmailProps with firstName, confirmUrl). 3. Use the Resend SDK in a Server Action or API route: resend.emails.send({ from: "Avo <hello@avogrowth.com>", to: user.email, subject, react: WelcomeEmail(props) }). 4. Add a test script that renders each template to HTML and checks that required props are present, unsubscribe links exist, and the output passes a basic email client rendering check. 5. For sequences (trial days 1, 3, 7), use a cron job that queries the database for users whose trial_started_at was N days ago and sends the appropriate template. Never rely on Resend's own scheduling for business-logic sequences. 6. Monitor bounce and complaint rates in the Resend dashboard. A bounce rate above 2% or complaint rate above 0.1% requires immediate list hygiene before sending resumes.

Resend replaced SendGrid as the provider in 2025. The reasons were developer experience (templates as code rather than drag-and-drop editors), simpler API surface, and first-class React Email support. Delivery rates are comparable at scale.

For client projects, Avo wires Resend as the default transactional provider unless the client has an existing SendGrid or Postmark account with high reputation. Domain authentication (SPF, DKIM, DMARC) is set up before any sends go out, not after.