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Resend alternative: Irisend vs Resend
Irisend's REST API, error catalogue and wire shapes are modelled directly on Resend's, so most of this comparison is about what happens after you're both sending mail: pricing shape, idempotency guarantees, and what an API key can do.
Facts below are sourced from Resend's own pricing page and docs, fetched 3 November 2026 — see the sources list at the bottom of this page. Irisend is in early access: every team sends free today (capped at 10,000 emails/month) regardless of plan; the prices below are Irisend's listed launch pricing, not yet billed.
Information checked on ; see sources at the bottom of this page. Facts come from Resend's own pricing and docs pages, recorded in docs/research/2026-11-03-competitor-comparison.md.
Feature by feature
| Feature | Irisend | Resend |
|---|---|---|
| Starting price | Free today (early access, 10,000 emails/mo cap, no credit card) · listed launch price from €20/mo | Free: $0/mo, 3,000 emails/mo, 100/day cap. Paid from $20/mo (50,000 emails/mo). |
| Price at 100,000 emails/mo (listed) | €35/mo listed launch price (Pro plan, 100,000 emails/mo) — not yet billed; every team sends free during early access | $35/mo (Pro plan, 100,000 emails/mo included)Same included volume as Irisend's listed Pro plan; currencies differ (USD vs EUR) and Irisend isn't billing this yet (early access), so compare listed rates, not current invoices. |
| Free tier | 3,000 emails/mo, 100/day cap, no overage, once the listed plans take effect | 3,000 emails/mo, 100/day cap, 3 domains, 1 webhook endpoint, 30-day retention |
| SMTP relay | smtp.irisend.com, ports 465 (implicit TLS) / 587 (STARTTLS) | smtp.resend.com, included on every plan |
| Idempotency key on send | Idempotency-Key header, 24h, checked against the request body (409 on a changed replay) | Idempotency-Key header (SMTP: Resend-Idempotency-Key), 24h — documented and available on every plan |
| Webhook signing | Standard Webhooks / Svix-compatible HMAC (byte-compatible with existing svix verifiers) | Svix-based (svix-id/svix-timestamp/svix-signature) |
| Sending regions | us-east-1, eu-west-1, sa-east-1, ap-northeast-1 — selectable per domain | us-east-1, eu-west-1, sa-east-1, ap-northeast-1 — same four regions, selectable per domain |
| Templates, broadcasts & audiences | Built in: versioned templates, broadcasts, audiences, topics and consent records in the same API and API key | Separate marketing product, billed by contacts rather than sends |
| AI / agent integration | Built in: an MCP server at /mcp — AI agents can send, look up emails and check domain health with an API key | AI assistant |
| DMARC monitoring | Built in: pass-rate summary, source breakdown, raw aggregate reports per domain | Not found on Resend's pricing/feature pages |
| Sub-accounts / multi-tenant | Built in: Connect sub-accounts with an embeddable React domain-verification widget | Not found on Resend's pricing/feature pages |
| Sandbox & test addresses | Built in: sandbox provider + dev inbox; bounced@, complained@, delayed@, opened@ and clicked@ simulate the full event lifecycle without sending | delivered@, bounced@, complained@ and [email protected] test addresses |
| Inbound email receiving | Built in: enable per verified domain (capabilities.receiving), email.received webhook, GET /emails/receiving + /:id + attachments endpoints, 1-hour signed download_url on the raw MIME and every attachment, plus a sandbox POST /dev/inbox/receive to simulate a delivery without real SMTP | Included on every plan, including Free: custom domains or a managed <id>.resend.app address, email.received webhook, Attachments API with a 1-hour download_url, raw MIME download via a signed CloudFront URLSame event name, same 1-hour download-URL TTL, same metadata-only webhook body — receiving code written for Resend ports over unchanged. |
| React Email in the official SDK | react: <Component /> on emails.send/sendBatch in the Node.js SDK, rendered via the optional peer dependency @react-email/render (lazily imported — never required unless you pass react) | react field on emails.send, documented as "Only available in the Node.js SDK" in Resend's own API reference |
What Irisend does that Resend doesn't
Idempotency has the same guarantees, documented the same way
Both APIs support a 24-hour Idempotency-Key; Irisend's additionally distinguishes a same-key-different-body replay (409 invalid_idempotent_request) from a genuinely concurrent duplicate (409 concurrent_idempotent_requests) rather than one generic conflict.
DMARC monitoring and sub-accounts ship today
Per-domain DMARC pass-rate, source breakdown and raw aggregate reports, plus Connect sub-accounts with an embeddable domain-verification widget — neither surfaced on Resend's published pricing/feature pages as of the date checked.
One flat overage rate instead of a volume ladder
Every Irisend paid plan and pay-as-you-go lists the same €0.70/1,000 overage rate; Resend's overage shrinks from $0.90 to $0.46/1,000 as the plan's included volume rises. During early access every team sends free, up to 10,000 emails/month.
An MCP server and a fuller sandbox
AI agents connect to Irisend's MCP server with a normal API key and get send_email, list_emails, get_email, list_domains, check_domain_health and explain_bounce tools. In the sandbox, bounced@, complained@, delayed@, opened@ and clicked@ addresses simulate the whole event lifecycle — including opens and clicks, beyond Resend's delivered/bounced/complained/suppressed test addresses — so webhooks can be tested end to end without sending real mail.
Sandbox-simulated inbound, no real SMTP traffic needed
POST /dev/inbox/receive feeds a synthetic inbound message straight into the same processing pipeline a real SES delivery uses, firing email.received without any mail crossing the internet. Resend's own receiving quickstart has you send a real email to a <id>.resend.app or verified custom-domain address to see one land; its test-email simulation (delivered@/bounced@/complained@/[email protected]) covers the sending side only, not an inbound delivery.
Verdict
Irisend gives you the Resend-shaped API you already know — same regions, same SMTP convention, same response shapes — plus a stricter idempotency contract, built-in DMARC monitoring, Connect sub-accounts, an MCP server for AI agents, inbound receiving with a sandbox simulation mode, React Email support in the Node SDK, and one flat overage rate. Switching is mostly a base URL and an API key, and every team sends free during early access.
Frequently asked questions
Related guides
Next
Read the full API reference, the Resend migration guide, or see pricing.
Sources (checked 3 November 2026)
- Resend pricing
- Resend idempotency keys
- Resend webhook verification
- Resend receiving emails (introduction)
- Resend email.received webhook
- Resend send-email API reference (react field)
Resend is a trademark of its respective owner. Irisend is not affiliated with, endorsed by, or sponsored by Resend. Spotted an inaccuracy? [email protected].