TL;DR — Quick Summary
Ark is the AI-first transactional email API built for the agentic era. It offers 26 MCP tools for complete email operations via AI assistants—including domain, suppression, and webhook management. Mailgun has an official MCP server but it's intentionally limited to sending and read-only analytics. Ark costs $0.50 per 1,000 emails with no monthly fees, while Mailgun uses tiered pricing starting at $15/month. Mailgun offers features Ark lacks—inbound email routing, EU data residency, and send time optimization—but Ark provides the comprehensive AI integration that Mailgun's conservative MCP approach doesn't match.
Ark vs Mailgun: Complete Comparison for 2026
Choosing between Ark and Mailgun for your transactional emails? This comprehensive comparison covers AI integration, pricing, deliverability, and developer experience to help you make the right choice.
Feature Comparison at a Glance
| Feature | Ark | Mailgun |
|---|---|---|
| MCP Tools for AI | 26 tools (official) | Limited (read-only) |
| MCP Capabilities | Full email ops + management | Send + analytics only |
| Base Price | No monthly fee | $15-90/mo |
| Per 1,000 Emails | $0.50 | $0.80-1.80 |
| 100K Emails/Month Cost | $50 | $90 |
| AI-Readable Docs | .md on all URLs | Standard HTML |
| Deliverability Rate | 99.9% | ~98% |
| Delivery Speed | Sub-second | 1-3 seconds |
| Batch Sending | 100 emails/request | 1,000 emails/request |
| Team Members | Unlimited | Varies by tier |
| Domains | Unlimited | 1-Unlimited (by tier) |
| Uptime SLA | 99.99% | 99.99% |
| Log Retention | Full retention | 5-30 days (by tier) |
| Inbound Email | Not available | Available |
| US & EU Regions | Global | US & EU |
AI Integration: The Defining Difference
Both Ark and Mailgun offer MCP (Model Context Protocol) servers, but the scope of capabilities differs significantly.
Ark MCP Server
Purpose-built for the agentic era with 26 tools covering every email operation.
Email Operations (7 tools)
- • send_email, send_batch (100 emails), send_raw (RFC 2822 MIME), get_email, list_emails, retry_email, get_deliveries
Suppression Management (5 tools)
- • check, add, bulk_add (1,000 addresses), remove, list
Domain Management (5 tools)
- • create, list, get, verify, delete
Webhooks (5 tools)
- • create, list, update, test, delete
Tracking Domains (4 tools)
- • create, list, verify, delete
Mailgun MCP Server
Mailgun offers an official open-source MCP server (github.com/mailgun/mailgun-mcp-server) with limited functionality. The server is intentionally read-only (except for email sending) to prevent accidental changes to production environments.
Email Operations
- • send_email
- Send emails via natural language prompts
Analytics & Reporting
- • get_delivery_statistics, get_bounce_logs, get_domain_settings, validate_email, generate_reports
- Read-only access to email metrics and configuration
Not Available via MCP
- No domain management via MCP (read-only)
- No suppression management via MCP
- No webhook management via MCP
- No batch sending via MCP
- No email retry capabilities
- Intentionally limited to prevent production changes
AI-Readable Documentation
Ark
- • Add
.mdto any documentation URL - • 10x fewer tokens than HTML for LLM consumption
- • Every page optimized for AI assistants
- • Predictable API responses designed for automation
Mailgun
- • Standard HTML documentation
- • Standard HTML documentation with code samples in multiple languages. No AI-specific documentation format like Ark's .md URLs.
Pricing Comparison
Ark offers transparent, single-tier pricing. Mailgun uses tiered pricing with different features per level.
Ark Pricing
No monthly fee. $2.50 (~5,000 emails) to start.
- All 26 MCP tools included
- Unlimited team members
- Unlimited domains
- 99.99% uptime SLA
- AI-readable documentation
- No negotiation needed
Mailgun Pricing
+ $0.80-1.80 (varies by tier) per 1,000 emails
- Trial: $0 (100/day for 3 months)
- Basic: $15/mo (10,000/month)
- Foundation: $35/mo (50,000/month)
- Scale: $90/mo (100,000/month)
Mailgun charges overage rates varying by tier ($0.40-1.80/1K). Extra dedicated IPs cost $59/IP/month. Mailgun Optimize (deliverability tools) is priced separately starting at $49/mo.
Cost at Different Volumes
| Emails/Month | Ark | Mailgun | Savings |
|---|---|---|---|
| 10,000 | $5.00 | $15 | 67% |
| 50,000 | $25.00 | $35 | 29% |
| 100,000 | $50.00 | $90 | 44% |
| 500,000 | $250.00 | $531+ | 53% |
| 1,000,000 | $500.00 | $1,081+ | 54% |
Calculations based on published pricing. Ark: $0.50/1K (no base fee).
Deliverability & Performance
Both services prioritize transactional email deliverability with excellent track records.
99.9%
Ark Deliverability Rate
Automatic SPF, DKIM, DMARC
~98%
Mailgun Deliverability
Sub-second
Ark Delivery Speed
vs 1-3 seconds (Mailgun)
Deliverability Features Comparison
Ark
- Automatic SPF, DKIM, DMARC setup
- Global delivery network
- Real-time webhook notifications
- Suppression list management
- Bounce handling
Mailgun
- Email validation
- Send time optimization
- US & EU regions
- Inbound routing
- Inbound email processing
Developer Experience
Both platforms offer comprehensive SDKs and documentation, with key differences in AI tooling.
Ark Developer Tools
SDKs
Python, Node.js, Ruby, Go
API
29 REST endpoints, SMTP relay, batch sending (100 emails/request)
AI Integration
26 MCP tools, Claude/Cursor/Windsurf/VS Code support
Documentation
AI-readable Markdown on all URLs, llms.txt
Mailgun Developer Tools
SDKs
Python, PHP, Ruby, Java, C#, Go, Node.js
API
REST API, SMTP, batch sending (1,000 emails/request)
AI Integration
2 MCP tools
Documentation
Standard HTML documentation with code samples in multiple languages. No AI-specific documentation format like Ark's .md URLs.
When to Choose Each Platform
The right choice depends on your specific needs and workflows.
Choose Ark When...
- You're building AI-powered workflows or using AI coding assistants
- You want AI agents to manage email operations autonomously
- You need predictable, automation-friendly API responses
- You're cost-conscious at scale (significant savings at volume)
- You want simple pricing without tiers or negotiations
- You use Claude, Cursor, Windsurf, or VS Code extensively
Choose Mailgun When...
- Teams needing inbound email processing
- Organizations requiring EU data residency
- Applications needing large batch sends
- HIPAA-compliant healthcare applications
- Teams using PHP, Java, or C# primarily
- Teams wanting some MCP integration for analytics
Frequently Asked Questions
What is the main difference between Ark and Mailgun?
Ark is built AI-first with 26 MCP tools for complete email operations through AI assistants—including domain management, suppressions, webhooks, and tracking domains. Mailgun has an MCP server but it's intentionally limited to email sending and read-only analytics to prevent production changes. Ark offers full control via AI, while Mailgun's MCP is designed for monitoring rather than management.
Which is cheaper, Ark or Mailgun?
Ark is cheaper at all volumes. At 100,000 emails/month, Ark costs $50 versus Mailgun's $90. Ark charges a flat $0.50/1K with no monthly base fee, while Mailgun requires tier subscriptions starting at $15/month with overage rates of $0.80-1.80/1K depending on tier. Mailgun's Optimize tools cost an additional $49-99/month.
Does Mailgun have an MCP server?
Yes, Mailgun offers an official open-source MCP server (github.com/mailgun/mailgun-mcp-server). However, it's intentionally limited to email sending and read-only analytics—you can query delivery stats, bounce logs, and domain settings, but cannot manage domains, suppressions, or webhooks. This contrasts with Ark's 26 MCP tools that enable full infrastructure management through AI.
Why is Mailgun's MCP server read-only?
Mailgun designed their MCP server to be intentionally read-only (except for sending) to 'give you the freedom to explore your data and configuration without risking accidental changes to your production environment.' Ark takes a different approach, trusting AI assistants with full management capabilities across all 26 tools.
Which has better email deliverability?
Ark claims 99.9% deliverability with automatic SPF, DKIM, and DMARC configuration. Mailgun reports approximately 98% deliverability. Ark delivers emails in sub-second times, while Mailgun typically delivers in 1-3 seconds. Both are reliable, but Ark edges out on speed and claimed deliverability.
Does Mailgun support inbound email?
Yes, Mailgun offers inbound email routing and parsing, which is a feature Ark does not provide. If your application needs to receive and process incoming emails, Mailgun is the better choice. Ark focuses exclusively on outbound transactional email delivery.
Can I store data in the EU with either service?
Mailgun offers both US and EU data residency options, allowing you to keep data in your preferred region. Ark uses a global delivery network. If EU data residency is a strict requirement for compliance, Mailgun may be preferable.
What SDKs are available for each platform?
Ark offers SDKs for Python, Node.js, Ruby, and Go. Mailgun has broader SDK support including Python, PHP, Ruby, Java, C#, Go, and Node.js. If you need PHP, Java, or C# SDKs specifically, Mailgun has an advantage.
Is there a free tier for either service?
Mailgun offers a trial with 100 emails/day for 3 months. Ark does not offer a free tier but provides a $2.50 welcome credit (~5,000 emails). Ark's philosophy is that free tiers create misaligned incentives.
The Bottom Line
Ark is the better choice for AI-powered development workflows needing full control. With 26 MCP tools compared to Mailgun's limited read-only MCP, Ark enables AI agents to manage complete email operations—from sending and tracking to domain configuration and suppression management. Mailgun's MCP is useful for monitoring but doesn't offer the management capabilities developers using AI assistants expect.
Mailgun is the better choice for teams needing inbound email processing, EU data residency for compliance, or HIPAA-compliant infrastructure. Its broader SDK support (including PHP, Java, C#), send time optimization, and large batch sizes serve enterprise use cases. The read-only MCP approach may appeal to teams concerned about AI making production changes.
On pricing, Ark wins at all volumes. At 100,000 emails/month, Ark costs $50 versus Mailgun's $90. Mailgun's tiered structure with separate Optimize pricing and varying overage rates ($0.80-1.80/1K) makes total cost harder to predict. Ark's flat $0.50/1K rate with no monthly base is more transparent.
If you're building AI-native applications and want full control through natural language, Ark's comprehensive MCP is unmatched. If you prefer a conservative MCP approach (read-only analytics), need inbound email, or require EU compliance, Mailgun is a solid choice—just expect more limited AI capabilities.
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