Mailgun and SendGrid are the two titans of the email API market. Both send billions of emails per month. Both are used by GitHub, Uber, and tens of thousands of developers. But when it comes time to choose, the nuances start to matter.
Websites: mailgun.com and sendgrid.com
Pricing: Which Is Cheaper
No need to do the math — here’s the table for 50,000 emails/month:
- Mailgun Foundation: $35/mo, dedicated IP included, email validation — 5,000 checks
- SendGrid Essentials: $19.95/mo, dedicated IP — separate ($29.95/mo), email validation — separate
SendGrid is cheaper at entry ($20 vs $35), but as soon as you need a dedicated IP (and you do for proper deliverability), the price jumps to $50/mo. Mailgun includes the IP in the base plan.
At the same time, SendGrid has a more generous free tier: 100 emails/day vs 100 emails/day on Mailgun (Mailgun Flex). It’s a tie.
For high volumes (>1M emails/month), prices converge — both offer custom plans through their sales teams.
Deliverability
The key metric for any email service. How many emails actually reach the Inbox, not Spam.
Mailgun built its reputation on transactional emails. Their IP pools are warmed by years of sending notifications from GitHub and Stripe. The inbox rate consistently stays above 97% for properly configured domains. Testing tools (email preview, spam score) are right in the dashboard.
SendGrid is strong in marketing campaigns. They have the industry’s best segmentation and A/B testing. But IP pool reputation is mixed: due to mass senders’ popularity, their addresses more often land on spam lists. SendGrid requires more careful SPF/DKIM/DMARC setup and reputation monitoring.
Verdict: for transactional emails (password resets, order confirmations) — Mailgun. For marketing campaigns — SendGrid, if you’re willing to monitor reputation.
SDKs and Documentation
Both have excellent SDKs for popular languages. Python, Node.js, Ruby, PHP, Java, Go, C# — all covered.
Mailgun documentation: detailed, with examples for every API method. A sandbox domain for testing. Good guides on deliverability best practices.
SendGrid documentation: part of the vast Twilio ecosystem. Twilio-style — quick starts, interactive examples, email design guides. SendGrid wins on educational material quality.
Analytics and Dashboard
Mailgun: functional, informative, but looks dated. Shows delivery rate, open rate, click rate, complaint rate, bounce classifications.
SendGrid: a modern interface in the Twilio Console style. Deeper marketing campaign analytics: A/B tests, segmentation, user behavior. A separate Email Activity Feed for searching specific emails.
Additional Features
Mailgun: email validation API (pre-send address checking), inbound routing (receiving emails via API), inbound parsing. A strong set for transactional scenarios.
SendGrid: Marketing Campaigns (visual email editor, templates, segmentation), A/B testing, dynamic templates with Handlebars, event-based automation. A marketing machine.
What this means: if you’re building a SaaS with notifications — Mailgun. If you’re doing email marketing for thousands of subscribers — SendGrid.
Vendor Lock-In and Maturity
Mailgun has been through several owners (Rackspace → Sinch). Development pace has slowed, but stability is solid. SendGrid was bought by Twilio in 2018 — integration with the rest of the Twilio ecosystem (SMS, Voice, WhatsApp) is a huge plus if you use those products.
What to Choose
Mailgun — for sending transactional emails from code. If your product sends notifications, password resets, order confirmations. More stable deliverability, cheaper dedicated IP. Downside: old interface, weak marketing features.
SendGrid — for email marketing and campaigns. If you send newsletters, promotions, onboarding sequences. Better analytics, A/B tests, segmentation. Downside: need to monitor reputation, dedicated IP costs more.
For many teams, the optimal setup is a tandem: Mailgun for transactional emails, SendGrid for marketing. But if you need a single service — choose based on your dominant use case.