Resend
Resend transactional email integration
MarginLock uses Resend for transactional email — alerts, reimbursement updates, magic-link auth. How it's wired and how to bring your own from-domain.
By MarginLock Team · April 22, 2026
MarginLock uses Resend for every piece of transactional email we send — magic-link sign-ins, alert notifications, weekly margin digests, and operational notices. Marketing emails (newsletters, product announcements) go through a separate path; this page is only about transactional traffic.
What gets sent
| When | |
|---|---|
| Magic-link sign-in | On every sign-in attempt, rate-limited to one per minute per address |
| Alert notification | When an Alert rule fires (margin threshold, overweight box, fee anomaly) |
| Reimbursement update | When a tracked reimbursement case advances state |
| Weekly margin digest | Mondays, summarising the prior week's settlements and fee adjustments |
| Invite | When a workspace owner invites a teammate |
That's the complete list. We don't drip-mail, we don't re-engage, and we never send marketing copy through the transactional pipeline.
Bring your own from-domain
By default, transactional mail is sent from notifications@marginlock.io. Paid
plans can swap this for their own domain in two steps:
Add the verification records
Add the SPF, DKIM, and (recommended) DMARC records that the workspace settings page generates for your domain.
Verify and activate
Once Resend confirms verification, flip the toggle in workspace settings. All future transactional mail will originate from your domain.
Rate limits and reliability
Resend's send limits are well above what any single workspace needs for transactional traffic. We additionally clamp magic-link sends server-side to one per minute per address — both to prevent accidental spam and to stop brute-force enumeration attacks against the sign-in endpoint.