Choose Resend if
- You're sending one-shot transactional mail (receipts, password resets) from a web app.
- Your team already knows the React Email ecosystem.
- No AI agent is involved — humans trigger every send.
Choose Loomal if
- An AI agent needs to receive and reply in-thread, not just send.
- The agent needs credentials, TOTP codes, or a scoped vault.
- You want revocation that cascades — kill the identity and every credential dies with it.
- Multiple agents need distinct addresses and isolated inboxes.
Feature-by-feature
| Feature | Loomal | Resend | Edge |
|---|---|---|---|
| Send email | mail.send primitive, DKIM-signed | resend.emails.send | |
| Receive email | Inbox per identity, webhook or poll | Inbound beta, routing only | |
| Thread stitching | Automatic In-Reply-To + References | Manual — you manage headers | |
| Extracted text for LLMs | Strips quoted history + signatures | Raw body only | |
| Credential vault | AES-256 per-identity vault | None | |
| TOTP / 2FA codes | vault.totp primitive | None | |
| MCP server | @loomal/mcp, first-party | Community-built only | |
| Template engine | None (bring your own) | React Email, first-party | |
| Analytics / open tracking | Delivery + bounce logs | Opens, clicks, deliverability dashboard | |
| Delegation chain | Cryptographic, cascades on revoke | None |
The category difference
Resend is a transactional email API. Its job is to take a message from your web app and get it delivered with good deliverability, nice templates, and useful analytics. The end user is a human who reads the email in Gmail; the sender is an app that knows what to send and when.
Loomal is email identity infrastructure for AI agents. Its job is to be the agent's email provider, not just its outbound relay. The agent sends, receives, threads, and acts on replies. Credentials and 2FA sit in the same identity because the agent needs them for the workflows that email drives.
Where the gap shows up
The honest moment to notice the gap is the first time your agent sends a message and waits for a reply. With Resend you add SendGrid Inbound Parse or set up a Postmark inbound address, reconcile threads by hand, then build your own credential store for whatever the reply triggers. With Loomal all of that is the default — the inbox is an API primitive, threading is automatic, and vault/TOTP live next door.
The second moment is credential management. An agent sending email usually also needs to log into something: a CRM, a database admin, a billing portal. Resend has no opinion on this; you bolt on a secrets manager and handle 2FA yourself. Loomal's vault and TOTP store are part of the same identity, so revoking the agent revokes everything it touched in one operation.
Can you use both?
Yes, and some teams do. Use Resend for your human-facing transactional mail (signup confirmations, password resets) and Loomal for your AI agents' mailboxes. They don't conflict — different senders, different use cases, different dashboards. The question is usually whether your agent-side workload has grown enough to justify the second integration, or whether you'd rather consolidate on Loomal for both.
FAQ
Does Loomal support React Email templates?
Render your React Email components to HTML and pass the result to mail.send. Loomal isn't opinionated about the template engine — bring whatever your team already uses.
Can Loomal send from my custom domain?
Yes, on paid plans. Configure SPF, DKIM, and DMARC records once and every identity on that domain signs with its own key.
Is Loomal's deliverability as good as Resend's?
Both rely on the same underlying MTA reputation model. Loomal DKIM-signs every message, handles SPF/DMARC alignment, and provides bounce + complaint logs. If you're sending at high volume from a custom domain, the sending-side story is comparable.
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Last updated: 2026-04-15