SendGrid suits businesses that want an email API and a marketing campaigns tool from one provider, now part of Twilio alongside SMS and voice. Mailgun suits developers who want sending, validation, inbox previews and inbound email parsing, with the option of EU-based domains. Both send reliably at scale, so choose SendGrid if you want marketing campaigns in the same account, and Mailgun if your developers want an email-only platform with EU data.
Both are transactional email services: they send password resets, receipts, alerts and newsletters from your app or website through an API or SMTP. I read SendGrid's home, plans and developer pages and Mailgun's home, plans and getting started guide, plus Google's Gmail sender guidelines.
SendGrid and Mailgun side by side
| SendGrid | Mailgun | |
|---|---|---|
| Company | Part of Twilio | Listed with Sinch Email and Mailjet |
| Sending | Email API and SMTP | Email API and SMTP |
| Newsletters | Marketing Campaigns product | Focus on sending and optimisation |
| Extras | Open-source SDKs | Email validation, inbox previews, inbound parsing |
| Data location | Not covered on the pages I read | US or EU based domains |
| Free option | Free trial, no credit card | Free plan with a daily cap, 1 user |
Free plans: read the small print
Mailgun's plans page says its free plan includes the fundamentals with a daily sending cap and is limited to one user, while paid plans come with free 30-day trials of higher-tier features such as longer log retention and SSO. It also says every plan except free and basic lets you add as many users as you need, which stops people sharing logins. SendGrid's page offers a free trial with no credit card required. Check the trial length and sending limits before you build anything that depends on them.
The Gmail rules both have to follow
Whichever service you choose, Google sets the rules for reaching Gmail inboxes. Its sender guidelines say every sender must set up SPF or DKIM and keep spam rates reported in Postmaster Tools below 0.3%. Anyone sending more than 5,000 messages a day to Gmail accounts must set up SPF, DKIM and DMARC. Both SendGrid and Mailgun support domain authentication, so set it up on day one.
Where each one stands out
Mailgun says it's built by developers for developers and lists four jobs: send, optimise, validate and inspect emails. Its inbound parsing routes replies and incoming email to your application, and you can add US or EU based domains, which helps if your customers or legal team want data kept in Europe. It says more than 150,000 businesses use it.
SendGrid's strength is breadth. Its email API sits beside a Marketing Campaigns product for newsletters, and because it's part of Twilio, you can manage email alongside SMS, WhatsApp and voice from one provider. Its documentation includes open-source SDKs for the main programming languages.
Setup checklist for either
- Verify your sending domain and add SPF, DKIM and DMARC records.
- Send transactional email from a subdomain separate from marketing email.
- Add one-click unsubscribe to marketing messages.
- Watch bounces and complaints for the first fortnight before you scale.
My email deliverability checklist walks through each step, and if you also need newsletters, compare options in my guide to email marketing software for small businesses.
Check emails before they go out
Mailgun's inspect tools let you preview emails before sending and fix common accessibility issues, and its validation service checks addresses before you send, which protects your sender reputation. SendGrid lists partners who can help you integrate its email API, improve deliverability or build a custom setup, which helps if you don't have an in-house developer.
My advice on SendGrid or Mailgun
If you want your app's email and your marketing campaigns in one account, or you already use Twilio for SMS, start with SendGrid's free trial. If your developers want an email-only platform with validation, inbound parsing and EU domains, start on Mailgun's free plan. Whichever you pick, set up authentication before your first send.
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Frequently asked questions
Does Mailgun have a free plan?
Yes. Mailgun's plans page lists a free plan with a daily sending cap, limited to one user.
Does SendGrid have a free trial?
Yes. SendGrid offers a free trial with no credit card required.
Can Mailgun keep data in the EU?
Mailgun's documentation says you can add US or EU based domains.
Does SendGrid do marketing emails?
Yes. SendGrid offers a Marketing Campaigns product alongside its email API.
What does Gmail require from senders?
Google says all senders need SPF or DKIM and spam rates below 0.3%, and senders of more than 5,000 messages a day also need SPF, DKIM and DMARC.
Can Mailgun receive emails?
Yes. Mailgun's inbound parsing routes incoming email to your application.
