What it does
MailerQ runs on Linux servers and provides a browser console for inspecting queues, SMTP attempts and sending limits. It is sold as a perpetual licence per instance, starting at EUR 10,000 for Regular, with updates and support charged annually. A one-month trial licence is available after the team reviews the intended setup.
A receiving domain's rate-limit response needs a different response from a permanently invalid address. MailerQ's flood patterns can override normal throttling when a server returns a specified error, temporarily pausing that destination and building connections back up afterward. Domains using the same receiving mail servers are grouped automatically for throttling.
The console shows in-memory and temporary RabbitMQ queues, live SMTP traffic and logs of failed attempts. A delivery operator can pause a source/destination combination, reroute traffic between IPs or force an error for deliveries that should be blocked. Use those views to identify the affected destination before changing a broad sending rule.
Regular costs EUR 10,000 per instance and permits 100,000 emails per hour across ten domains. Enterprise costs EUR 25,000 per instance and removes those licence limits. Annual updates and support cost EUR 2,000 and EUR 5,000 respectively, in addition to the perpetual licence. These allowances describe the licence, not a promise of real-world delivery speed.
A trial request asks for your name, company and work email, plus details of expected volume, sending IPs and existing delivery problems. An expert reviews the setup before arranging the trial licence, which is valid for one month. Installation requires Linux, RabbitMQ and the licence file.
Strengths
- Response patterns can change throttling for specific receiving-server errors
- Live queue and SMTP views support investigation of delivery attempts
Watch out for
- Updates and support require an additional annual payment
- The Regular licence has hourly message and domain limits
Best for
- Email operations teams running and controlling their own high-volume delivery infrastructure
Sources
- A high performance Mail Transfer Agent (MTA) | MailerQ (Oct 26, 2026)
- Management Console | MailerQ (Oct 26, 2026)
- MailerQ Pricing (Oct 27, 2026)
- Request a free trial (Oct 27, 2026)
- Getting started with MailerQ (Oct 27, 2026)
- License file (Oct 27, 2026)