Mailrun Review: Pricing, Capacity, and Product Facts
Looking for a Mailrun review? This page is written by Mailrun. It covers current pricing, what the service includes, how we plan capacity, and how to reach us.
Product Information Verified August 23, 2026
The Infrastructure Layer for Outbound Email
Mailrun provides and operates inboxes and domains for teams sending outbound email across multiple domains. Mailrun handles provisioning, authentication, infrastructure monitoring, and remediation. Customers control their campaign strategy and execution.
Mailrun Operates
- Inbox provisioning on Microsoft Azure
- SPF, DKIM, and DMARC configuration
- Sequencer-ready credentials and handoff files
- Infrastructure monitoring and remediation
You Control
- Campaign strategy and sending decisions
- Lead sources, targeting, and suppression lists
- Copy, offers, and reply handling
- Sequencer settings and campaign schedules
Starter Begins at $129 per Month
The Starter plan supports ten domains and up to 100 inboxes. This price is BYOD: bring your own domains.
Why Mailrun Uses a Wider Domain Base
Mailrun caps each domain at ten inboxes. For planning, we use five campaign sends per inbox per business day. That is a capacity-planning rate, not a mailbox cap.
A target of 300 campaign sends per business day uses 60 inboxes across six domains. One ten-inbox domain represents 50 planned sends, or 16.7% of that domain-level capacity.
Replies and ordinary one-to-one messages are not included in the campaign-send calculation.
6 domains
Each domain carries one-sixth of the planned domain-level capacity in this example.
Built on Microsoft Azure and Managed by Mailrun
Mailrun inboxes are not Microsoft 365 or Exchange Online accounts. Mailrun manages the inbox and domain infrastructure running on Microsoft Azure.
Questions to Ask Any Infrastructure Provider
Receiver and infrastructure references: Gmail Email Sender Guidelines and Microsoft Azure Communication Services Email Overview.
Direct Answers Before You Buy
Common Questions About Mailrun
What Is Mailrun?+
Mailrun provides and operates outbound email inboxes and domains for agencies, sales teams, and other organizations that need sending capacity across multiple domains. Mailrun handles provisioning, authentication, infrastructure monitoring, and remediation. Customers control their campaign strategy and execution.
Are Mailrun Inboxes Microsoft 365 or Exchange Online Accounts?+
No. Mailrun inboxes run on Microsoft Azure infrastructure and are managed by Mailrun. They are not Microsoft 365 or Exchange Online accounts.
Does Mailrun Limit Inboxes to Five Sends per Day?+
No. Mailrun uses five campaign sends per inbox per business day to plan pool capacity. It is not a mailbox cap, and it does not include replies or ordinary one-to-one messages.
Does Mailrun Provide API Access?+
Customer API access is available for approved deployments after onboarding. Confirm the endpoints and workflow you need during the planning process.
Can I Speak Directly With Mailrun?+
Yes. You can book a planning call directly with Brian Brackeen, Mailrun's founder, before purchasing or sizing a larger deployment.
Talk Through Your Sending Plan.
We'll review your domain count, inbox capacity, timing, and API requirements before you buy.