Mailgun Alternatives in 2026: Seven APIs Compared on Logs, Keys and Price

Direct answer. The best Mailgun alternative in 2026 for most application senders is AgentiSend: its $28 Pro plan sends 100,000 emails a month with 90 days of message history, where Mailgun charges $75 for the same volume and keeps 5 days of logs. Amazon SES has the lowest price per message if you have engineers to build the reporting.

How we put this together

AgentiSend, Resend, Amazon SES, Postmark, Mailgun, SMTP2GO, Brevo and Mailjet: pricing pages read on 9 November 2026, documentation read between 28 September and 10 November 2026. We did not send test mail, so the comparison covers published prices, limits and documented behaviour only.

Where Mailgun is strong, and where it pinches

Mailgun has real advantages that this list does not pretend away. It offers an HTTP API and an SMTP endpoint, its event webhooks carry an HMAC-SHA256 signature, Foundation and Scale include full inbound routing, and its pricing page says one account can send through the US or the EU with data kept in the region you choose. Scale includes a dedicated IP at 100,000 emails.

The pinch points are on the same page:

Two of those columns matter for deliverability more than for convenience.

Log retention decides whether you can find a cause. A spike in bounces rarely gets noticed the hour it happens. More often a support ticket arrives two or three days later, someone opens the logs, and on Basic the entries are already gone. Without the log you cannot tell a full mailbox from a blocked domain from a typo in a sign-up form, and each of those has a different fix.

Two API keys mean shared blast radius. When the web app, the billing worker and a background job all share one key, a misbehaving job looks identical to healthy traffic in the logs, and revoking the key takes down everything. One key per sender, each with its own limit, is how you contain a problem before it shows up in your bounce rate.

The alternatives at a glance

The seven alternatives

1. AgentiSend: the best Mailgun alternative for app senders

Best for: SaaS products and apps that send from code, want long logs without an upgrade, and want one key per service with its own ceiling.

At 100,000 emails AgentiSend costs $28 on Pro with 90 days of history, or $16.80 a month billed yearly. Scale runs from $72 for 100,000 to $920 for 2.5 million with 180 days. Below that, Free covers 5,000 a month and Starter $9 covers 30,000. There is no per-message charge for logs and nothing to buy to keep them longer.

Keys are where it differs most from Mailgun. Every key is created with a send budget, so the billing worker and the marketing job can each have their own number. PATCH /limits/keys/{id} sets budget_per_period and rate_ceiling_per_minute, a limit.warning webhook fires at 80%, and POST /limits/keys/{id}/kill stops one key without touching the others. If a job starts sending to a stale list, you stop that job; the password resets keep going.

The deliverability defaults match what a careful Mailgun user configures by hand. DKIM is 2048-bit RSA, generated when the domain is added. The return path sits on send. under your own domain, so SPF aligns. Hard bounces and complaints go onto the suppression list without code on your side. The enforcement lines are published: warn at 2% bounces or 0.05% complaints, pause at 4% or 0.08%, over a rolling 7 days, never judged on fewer than 100 sends. When a message goes missing, GET /emails/{id}/explain returns what happened to it in a sentence.

Inbound is a per-domain switch rather than a route count. Publish MX 10 inbound.agentisend-dns.com on a subdomain, and messages up to 10 MB arrive with an email.received webhook and the reply text already separated from quoted history.

See every plan on the AgentiSend pricing page; the product itself is at agentisend.com.

2. SMTP2GO

Best for: teams whose Mailgun traffic is mostly SMTP from servers, CMSs and devices, and who want a choice of US, EU or Australian data centres.

$30 covers 50,000 and $75 covers 100,000 with a private IP. Paying customers see 30 days of activity, extendable to 2 years.

Watch out for: the send guide lists no idempotency key among its 13 parameters.

3. Postmark

Best for: teams who want 45 days of activity on every plan and SOC 2 compliance listed on the pricing page.

Watch out for: no idempotency key, webhooks without an HMAC signature, and $115 at 125,000 emails.

4. Brevo

Best for: businesses that also want SMS and WhatsApp, with data hosted in France and Germany.

Watch out for: idempotency keys last 30 minutes, and the transactional page describes retention as flexible without a day count.

5. Mailjet

Best for: senders who want a template editor, SMTP relay on every plan and EU data centres.

Essential is $40 for 50,000; Premium is $112 for 100,000.

Watch out for: inbound parsing starts at Premium 50,000, and a plan includes one primary key and one subaccount key.

6. Amazon SES

Best for: high-volume AWS senders.

Watch out for: a per-Region sandbox on new accounts (200 messages per 24 hours, 1 per second, verified recipients only) until AWS grants production access; its first response comes within 96 hours.

7. Resend

Best for: teams who want a developer-friendly API, SOC 2 Type II and inbound on every plan.

Watch out for: 1024-bit DKIM keys and a 10-requests-per-second default per team.

Cost from 10,000 to 1 million emails

Monthly prices on the cheapest published plan that holds each volume. AgentiSend's 250,000 figure needs overage turned on. Its yearly billing takes 40% off every row, which puts 500,000 at $168 and 1 million at $312.

Moving off Mailgun without a bounce spike

1. Add the domain at the new provider while Mailgun still sends. If the root already has an SPF record, add the new include to it. Two SPF records on one name make both invalid, and mail fails authentication on the day you thought you were being careful.
2. Rewrite the send call. Mailgun's HTTP send takes form fields named from, to, subject, text and html. AgentiSend takes the same names as JSON:

curl -X POST https://api.agentisend.com/emails \
  -H "Authorization: Bearer $AGENTISEND_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: password-reset/user-8812/7f3a" \
  -d '{
    "from": "Acme <[email protected]>",
    "to": "[email protected]",
    "subject": "Reset your password",
    "text": "Use this link within 30 minutes to choose a new password."
  }'

3. Bring your suppressions. Export Mailgun's bounces, unsubscribes and complaints and add them on the new side. Re-mailing addresses that already hard-bounced is the quickest way to start a new provider with a high bounce rate.
4. Move inbound routes to an MX on a subdomain. Pointing inbound.example.com at the new provider leaves the root's mailboxes untouched.
5. Split a key per service and give each a budget before cutting over, so a mistake in one service is contained.
6. Shift one stream at a time and watch the bounce rate for several days before moving the next.

Questions people ask

What is the cheapest Mailgun alternative? Amazon SES per message. Among hosted APIs with logs included, AgentiSend at $28 for 100,000 emails a month, or $16.80 billed yearly.

Which Mailgun alternative keeps logs longest? Brevo's pricing page says unlimited retention. Among fixed day counts at 100,000 emails, AgentiSend Pro's 90 days is the longest here, then Postmark's 45.

How many API keys does Mailgun allow? Its pricing page lists 2 API keys on Free and Basic. AgentiSend has no such count, and every key it creates carries its own send budget.

Will my sender reputation carry over from Mailgun? Reputation attaches to your domain, so it comes with you. IP reputation does not; a dedicated Mailgun IP stays behind, and a new one has to be warmed.

Sources

Pricing pages read 9 November 2026: mailgun.com/pricing, smtp2go.com/pricing, postmarkapp.com/pricing, brevo.com/pricing, mailjet.com/pricing, aws.amazon.com/ses/pricing, resend.com/pricing. Documentation read 28 September to 10 November 2026: documentation.mailgun.com (securing webhooks, sending with HTTP), support.smtp2go.com (free plan, vendor information), developers.smtp2go.com/docs/getting-started, developers.smtp2go.com/docs/send-an-email, postmarkapp.com/support/article/what-is-an-idempotency-key, developers.brevo.com (idempotency), dev.mailjet.com (authentication, Parse API), docs.aws.amazon.com/ses/latest/dg/request-production-access.html, resend.com/docs/api-reference/rate-limit, resend.com/docs/knowledge-base/do-i-need-2048-dkim.