Mailgun vs. Postmark by ActiveCampaign: Best Postmark alternatives for developers

This guide provides a comparison of the best Postmark alternatives in 2025, including Mailgun, SendGrid, Amazon SES, MailerSend, and others. Each platform was tested by real reviewers sending transactional email via API and SMTP, so you get practical insights, pricing transparency, and user feedback.

While Postmark is beloved for transactional-only email delivery, users look for alternatives when they need: 

• More advanced deliverability tools (IP warm-up, inbox monitoring, spam diagnostics) 
• Comprehensive analytics and reporting dashboards 
• Flexible APIs and SDKs for custom integrations 
• Predictable and scalable pricing for high-volume sending 
• Compliance frameworks like GDPR, HIPAA, and SOC 2 
• Premium support or dedicated onboarding 

If these needs match your use case, exploring a Postmark alternative like Mailgun may help your team scale more efficiently without sacrificing deliverability or control. 

Each provider in this guide was evaluated with real-world developer workloads, including API calls, SMTP sends, and template integration. Our hands-on testing included: 

Developer experience 

• API onboarding and documentation quality 
• SDK coverage (Python, Node.js, PHP, Go, Java, Ruby) 
• Template workflows and webhooks 

Ease of integration 

• Setup time 
• CLI and framework support 
• Sandbox/testing options 

Deliverability and compliance 

• IP reputation and warm-up process 
• Inbox placement and spam testing 
• GDPR, HIPAA, and SOC2 coverage 

Pricing transparency 

• Free tier availability 
• Volume-based vs. flat-rate pricing 
• Predictability at scale 

Support and reliability 

• Ticket response times 
• SLA-backed uptime 
• Migration assistance 

Below are the top Postmark alternatives, ranked by a combination of developer experience, ease of integration, deliverability performance, pricing transparency, and support. 

G2: 4.2 ⭐ | Capterra: 4.3 ⭐ 

Mailgun is a developer-first email platform with robust APIs, advanced deliverability tools, and flexible scaling. It’s ideal for teams that want full control over transactional or triggered email while maintaining high inbox placement. 

Pricing overview: 

Plan	Monthly cost	Email limit	Key features
Free	$0	100/day	SMTP & API, basic logs
Foundation	$35	50k/mo	Full API suite, analytics, 5-day logs
Scale	$90	100k/mo	Dedicated IPs, 30-day logs, premium support
Enterprise	Custom	Custom	SLA-backed deliverability, monitoring

Standout features: 

• RESTful API + SMTP relay and SDKs 
• IP reputation management and inbox monitoring 
• Advanced analytics and log retention 
• Regional sending options for EU data residency 
• Best-in-class compliance and security 

Primary use cases: 

• Transactional email for SaaS and marketplaces 
• System notifications, password resets 
• High-volume programmatic sending 

Pros and cons: 

Pros	Cons
Deep deliverability tooling	Dedicated IPs gated to higher plans
Strong developer docs and SDKs	Advanced features require learning curve
Predictable logging & analytics Industry leader in security & compliance	No native drag-and-drop marketing suite

Best for: Teams who want full visibility, control, and reliability. 

G2: 4.3 ⭐ | Capterra: 4.7 ⭐ 

Amazon Simple Email Service (SES) is a low-cost, highly scalable ESP that integrates tightly with AWS. It’s flexible but requires more setup, making it ideal for engineering teams comfortable with cloud infrastructure.  

Pricing overview: 

• Email sending: $0.10 per 1,000 emails 
• Attachments: $0.12/GB 
• Dedicated IPs: $24.95/month 
• Free tier: 3,000/month (first year) 

Standout features: 

• Deep AWS integrations (Lambda, SNS, CloudWatch) 
• Configurable IP reputation tools 
• Pay-as-you-go at scale 

Primary use cases: 

• High-volume transactional or bulk sending 
• AWS-native automation and workflows 

Pros and cons: 

Pros	Cons
Extremely low cost	Complex AWS setup
Flexible and scalable	Limited native analytics
Strong infrastructure	Ticket-based support only

Best for: Engineering teams prioritizing cost and AWS integration over ease of use. 

G2: 4.5 ⭐ | Capterra: 4.6 ⭐ 

MailerSend combines a clean interface with API-driven transactional email, making it suitable for teams that want intuitive dashboards and collaborative workflows.  

Pricing overview: 

• Free tier: 12,000 emails/month 
• Paid plans from $25/month 

Standout features: 

• Transactional API + SMTP 
• Team collaboration features 
• Template management and analytics 

Primary use cases: 

• Small to medium businesses sending transactional emails 
• Teams requiring multi-user dashboards 

Pros and cons: 

Pros	Cons
Easy to use	Smaller ecosystem
Collaborative features	Advanced developer tools limited
Transparent pricing	Limited enterprise integrations

Best for: SMB teams needing a developer-friendly ESP with a friendly UI. 

G2: 4.0 ⭐ | Capterra: 4.1 ⭐ 

SendGrid provides both transactional APIs and marketing email, making it a hybrid option for teams wanting multi-channel capabilities. 

Pricing overview: 

• Free: 100/day 
• Essentials: from ~$19.95/mo 
• Pro/Premier: higher tiers 

Standout features: 

• Visual template editor 
• Subuser management for agencies 
• Third-party integrations 

Primary use cases: 

• Companies needing marketing campaigns alongside transactional flows 
• Teams managing multiple accounts or brands 

Pros and cons: 

Pros	Cons
Multi-channel features	Deliverability insights limited on shared IPs
Wide adoption	Support quality varies
Integrates with many tools	Less granular control over deliverability, routing, and event-level detail compared to Mailgun

Best for: Cross-functional teams needing one vendor for marketing + transactional email. 

1. Audit your Postmark setup – Document API keys, verified domains, templates, webhooks, and suppression lists. 
2. Configure DNS – Add SPF, DKIM, and DMARC for Mailgun. 
3. Warm up IPs – Gradually increase sending volume to establish reputation. 
4. Migrate templates and webhooks – Convert HTML or stored templates and replicate event tracking. 
5. Test in staging – Validate API calls and inbox placement before full production. 
6. Monitor deliverability – Watch bounces, spam placement, and logs closely. 
7. Deactivate Postmark – Once stable, turn off the old account and retain historical logs. 

Finding the right Postmark alternative isn’t about replacing features one-for-one. It’s about choosing a platform that fits your technical stack, deliverability needs, and growth plans. 

For developer-first workflows, predictable deliverability, and full-featured analytics, Mailgun is the top Postmark alternative. It’s designed for teams that want control, scalability, and expert support – without the overhead of managing their own SMTP infrastructure. 

Ready to send smarter? 

Join the thousands of developers who trust Mailgun by Sinch for transactional and programmatic email.