Resend vs Mailgun: two email APIs, two ways to grow
Resend costs less than Mailgun at every volume where both publish a price: $35 against $75 at 100,000 emails a month, and $350 against $400 at 500,000. Mailgun's plans carry more of the old-school send infrastructure, with US and EU sending, inbound routes, email validation and signed webhooks. Resend's plans carry a cleaner API, a free plan that never expires and a marketing side for onboarding sequences.
By Julian Pryor · Updated 7 Oct 2026
Short answer
Resend is the better default for a new SaaS that sends up to a few hundred thousand emails a month: lower price, a permanent free tier and fewer plan cliffs. Mailgun earns its premium when you need EU sending from one account, inbound routing, email validation or one included dedicated IP at 100,000 emails, and when you want to pay for log retention rather than build it.
Monthly price, volume by volume
The stops on the two sliders do not match, so some cells show the nearest published volume. Prices are from Resend's and Mailgun's pricing pages, read on 7 October 2026.
| Monthly emails | Resend | Mailgun | Mailgun premium per year |
|---|---|---|---|
| About 3,000 | Free: 3,000 a month, 100 a day | Free: 100 a day (about 3,000 over 30 days) | None |
| 10,000 | Pro $20 (includes 50,000) | Basic $15 | Mailgun $60 cheaper |
| 50,000 | Pro $20 | Foundation $35 | $180 |
| 100,000 | Pro $35 | Foundation $75 | $480 |
| 100,000, top plan | Scale $90 | Scale $90 | None |
| 200,000 to 250,000 | Scale at 200,000: $160 | Scale at 250,000: $215 | Not comparable |
| 500,000 | Scale $350 | Scale $400 | $600 |
| 1,000,000 | Scale $650 | No readout | Not available |
The premium column is the monthly difference times 12: at 100,000 emails ($75 - $35) x 12 = $480, at 500,000 ($400 - $350) x 12 = $600. The one place Mailgun is cheaper is a product that sends between 3,000 and 10,000 emails, because its $15 Basic plan costs less than Resend's $20 Pro, which then includes 50,000. Resend charges $0.90 per 1,000 for extra emails on Pro and Scale and $0.70 at the 500,000 stop. Mailgun lists extra emails from $1.30 per 1,000 on Foundation and from $1.10 on Scale.
Per 1,000 emails the curves look different. Resend Pro falls from $0.40 at 50,000 ($20 / 50) to $0.35 at 100,000, then Scale reads $0.80 at 200,000 ($160 / 200), $0.70 at 500,000 and $0.65 at 1,000,000. Mailgun reads $0.70 at 50,000, $0.75 at 100,000, $0.86 at 250,000 and $0.80 at 500,000. Resend's cheapest zone is 50,000 to 100,000 emails on Pro; past 100,000 it moves to Scale and the advantage over Mailgun narrows to 10 cents per thousand at 500,000 ($0.80 against $0.70).
Limits that decide the plan, not the volume
- Domains. Resend: 3 on Free, 10 on Pro, 1,000 on Scale, plus 100 more for $20 a month. Mailgun: 1 on Free and Basic, 1,000 on Foundation and Scale. Mailgun's Foundation reaches 1,000 domains at $35; Resend needs Scale at $90.
- Log retention. Mailgun: 1 day on Free and Basic, 5 days on Foundation, 30 days on Scale. Resend's Free plan lists 30-day data retention.
- Webhook endpoints. Resend: 5 on Pro, 10 on Scale. Mailgun's page lists webhooks on every plan, set at account or domain level, without a stated endpoint count.
- Single sign-on. Resend sells SSO as a $150-a-month add-on on Scale. Mailgun includes SAML SSO on Scale.
- Support. Mailgun's Scale adds live phone and chat support. Resend's Scale adds a dedicated Slack channel.
Webhooks compared
Resend documents eleven email events, from email.sent and email.delivered to email.bounced, email.complained and email.suppressed. It signs requests with svix-id, svix-timestamp and svix-signature headers, retries along an eight-step schedule that ends with two 10-hour waits, disables an endpoint that keeps failing and lets you replay failed or succeeded messages by hand (Resend retries and replays).
Mailgun's events are accepted, delivered, temporary_fail, permanent_fail, opened, clicked, unsubscribed and complained. Its signature is a hex HMAC-SHA256 of the timestamp and a 50-character token with your Webhook Signing Key, shared across every domain in the account (securing webhooks). Retries run for 8 hours after 5, 10, 15 minutes, 1, 2 and 4 hours, and a 406 response tells Mailgun not to retry (retries). After a handler outage longer than 8 hours, events Mailgun has stopped retrying have to be recovered from its logs, which keep 5 days on Foundation.
Dedicated IPs once you outgrow shared sending
Resend offers a dedicated IP for $30 a month, to Scale customers sending more than 3,000 emails a day. Mailgun's page says one dedicated IP is included with Foundation 100k and Scale, with additional IPs at $59 each a month. At 500,000 emails Resend Scale plus an IP is $350 + $30 = $380, and Mailgun Scale is $400 with one IP included, so the gap shrinks from $50 to $20 a month. A second Mailgun IP would bring the total to $400 + $59 = $459.
Which fits a SaaS lifecycle
Resend's marketing tab covers broadcasts and automations. Its free tier gives 10,000 automation runs a month and each run beyond costs $0.0015, so a trial-ending automation that fires 30,000 times in a month costs (30,000 - 10,000) x $0.0015 = $30 in run charges. Mailgun's pricing page describes mailing lists, recipient variables, templates and send time optimization on Scale, which is a sending toolkit rather than a journey builder. Neither pricing page mentions a Stripe or Paddle connector, so billing events reach either one through your own server code.
Which to choose
- Choose Resend if you send between 20,000 and 200,000 emails a month, want a free tier to start on, or want lifecycle automations in the same account.
- Choose Mailgun if EU sending, inbound routes, address validation or an included IP at 100,000 emails matter more than a $480 yearly premium.
- Reconsider at 500,000 emails. The difference is $50 a month ($400 against $350), so retention, IPs and support decide.
Switching from Mailgun to Resend
- Add your sending subdomain in Resend and publish SPF and DKIM next to Mailgun's records without removing them.
- Export Mailgun's bounces, complaints and unsubscribes and import them as suppressions before any live send.
- Replace Mailgun routes and the HMAC verifier with Resend's webhook endpoint and Svix signature check.
- Move template rendering into your code or Resend's dashboard if you relied on Mailgun's template API.
- Shift one message type at a time and leave payment notices on Mailgun until a week of clean bounce and complaint data.
Related reading: all comparisons, Resend vs SparkPost, Mailgun vs SparkPost, SendGrid vs Mailgun and email tools.
Resend vs Mailgun: common questions
Which is cheaper, Resend or Mailgun?
Resend, at every volume where both list a price. At 50,000 emails Resend Pro is $20 and Mailgun Foundation is $35. At 100,000 it is $35 against $75, a $480 difference over a year. At 500,000 Resend Scale is $350 and Mailgun Scale is $400. The gap is widest in the middle and shrinks after 250,000 emails.
Does Mailgun sign its webhooks like Resend does?
Yes. Mailgun adds a timestamp, a token and a signature, an HMAC-SHA256 of the first two keyed with your account's Webhook Signing Key. Resend signs with Svix headers and also lets you replay any message from the dashboard. Mailgun retries for 8 hours; Resend's schedule runs longer, to roughly 28 hours of attempts across eight tries.
Which has the higher domain limit?
It depends on the plan. Resend allows 3 domains on Free, 10 on Pro and 1,000 on Scale, with 100 more for $20 a month as an add-on. Mailgun allows 1 domain on Free and Basic and 1,000 on Foundation and Scale. An agency sending on behalf of many clients reaches Mailgun's limit at $35 and Resend's at $90.
Do either of them send marketing email as well?
Resend does: its marketing tab is free up to 1,000 contacts, then $40 at 5,000 contacts and $80 at 10,000, with automations that give 10,000 free runs a month and charge $0.0015 per run beyond that. Mailgun's pricing page lists mailing lists and recipient variables for sending, but no campaign or automation builder. A SaaS that wants onboarding sequences should look at Resend's side or at a lifecycle tool.
Is it hard to move from Mailgun to Resend?
It is mostly DNS, an API key swap and a new webhook consumer. The pieces that take time are your suppression list, any inbound routes you built on Mailgun, and the template system if you used Mailgun's template API. Run both vendors side by side on separate subdomains for a week before cutting payment mail over.