MailerSend vs Mailgun: Transactional Email API Compared

MailerSend is the transactional arm of MailerLite, built for product teams that want templates and a friendly dashboard; Mailgun is the veteran API that developers have wired into everything since 2010. Both send receipts and alerts reliably, both offer SMTP and REST, and both have inbound routing. The choice comes down to who on your team will use it and what your volume looks like.

Quick answer

MailerSend suits teams where marketers and developers share the tool: drag-and-drop templates, a simple analytics view and a free tier for getting started. Mailgun suits engineering-led teams that want a mature API, detailed logs, EU region choice and pricing that scales. Neither provides mailboxes. OquMail is the free choice when a small business needs both inboxes and a modest send API on one domain.

Feature comparison

• Mailboxes: neither; both are sending platforms with inbound parsing
• Free plan: MailerSend offers a small free monthly allowance; Mailgun offers a small free tier with a daily cap
• API: both have REST APIs, official SDKs and SMTP relay; MailerSend adds a template editor and SMS on paid plans
• DNS guidance: both require SPF and DKIM on the sending domain plus a Return-Path CNAME, verified in the dashboard
• IMAP/SMTP: SMTP sending only; no IMAP on either
• Storage: activity and log retention is limited by plan on both; MailerSend stores templates, Mailgun stores stored messages briefly

Where MailerSend wins

• Visual template builder that non-developers can edit safely
• Cleaner analytics and a suppression list interface designed for humans
• Shares an account family with MailerLite for marketing campaigns
• Inbound routing and email verification included on paid plans

Where Mailgun wins

• API maturity, extensive docs and a large base of community libraries
• US and EU regions for data residency
• Send-time optimisation and validation tools on higher tiers
• Better fit for very high volume with dedicated IP pools

Total cost at 5 and 15 users

Both bill by monthly email volume, not by staff. At a few thousand messages a month either can be free or a small monthly amount; MailerSend's free allowance is friendlier for a product still in beta. Neither includes mailboxes for 5 or 15 people, so budget for an email host too.

The free third option: OquMail

OquMail is for the small business that would rather not run two vendors. The free plan gives 15 mailboxes with 5 GB each on up to 3 domains, IMAP and SMTP for any client, and a send API that takes from, to, subject and html with a Bearer key. When volume outgrows it, move transactional sending to MailerSend or Mailgun and keep the mailboxes.

• Free plan: up to 15 mailboxes, 3 domains, 5 GB per mailbox, no credit card
• Webmail included; IMAP/SMTP for Outlook, Apple Mail, Thunderbird and phones
• IMAP mail.oqumail.com port 993 (SSL/TLS); SMTP mail.oqumail.com port 587 (STARTTLS)
• Guided SPF, DKIM and DMARC with live DNS verification; MX is mail.oqumail.com priority 10
• Transactional send API at https://api.oqumail.com/api/v1/emails with Bearer API keys (from, to, subject, html)
• Per-message delivery logs so you can see the exact response a receiving server gave

Verdict by scenario

• Product team where marketing edits transactional templates: MailerSend
• Engineering team wiring email into a backend with EU residency: Mailgun
• Company already on MailerLite for newsletters: MailerSend
• Small business needing inboxes plus order confirmations: OquMail

Common questions

Is MailerSend the same as MailerLite?

They are sibling products from the same company. MailerLite is for newsletters and marketing automation; MailerSend is for transactional email and SMS from your application.

Does Mailgun still have a free plan?

Mailgun offers a limited free tier with a daily sending cap suitable for testing and very low volume. Production sending generally moves to a paid tier.

Do I need a separate inbox if I use either API?

Yes. Replies to your transactional mail need a mailbox. OquMail gives you that free on the same domain, with delivery logs for the messages you send through its API.

How do I keep two senders on one domain from breaking SPF?

Put every sender in a single SPF record; two SPF TXT records cause a PermError. Give each provider its own DKIM selector so signatures do not clash, and set DMARC to p=none while you confirm both align. OquMail's DNS checker flags a duplicate SPF record before it costs you deliverability.