Momentum MTA

Build the email pipeline your operation needs.

Run Momentum on infrastructure you control and customize how your email is processed and delivered. Discuss your sending volume, routing policies and operating environment with our MTA team to plan a deployment for your requirements.

Send your requirements. Our team will follow up by email about deployment and support.

Momentum

A programmable delivery path

Messages from your applications

01

Process

Apply your message-processing workflow.

02

Apply policy

Choose routing and delivery behavior.

03

Deliver and adapt

Respond to receiving-server conditions.

Adaptive Delivery

Delivery responses inform sending behavior.

Architecture illustration. Your team operates the infrastructure and configures processing, policies and delivery for its requirements.

Powerful email infrastructure

Whatever your tech stack looks like, and no matter what your sending requirements are, Momentum can be tailored to fit your business.

International support

Bird's the first commercial MTA to provide SMTPUTF8 support, allowing emails with Unicode characters in mail header fields. Reach audiences worldwide with comprehensive language support.

Control your sending workflow

The brain of the platform lets you develop customized workflow rules. Support your unique business processes with flexible policies. Create tailored sending strategies.

Enterprise-grade protection

TLS encryption ensures compliance with industry standards and improved brand protection by securing emails during transport. Supporting the latest SMTP authentication and accreditation techniques.

Lightning-fast delivery

Send messages at lightning speed and extraordinarily high volumes, according to your precise instructions, ensuring reliable email delivery at scale.

Outbound controls

Control the way messages are sent: mail is segregated according to your rules, with individual delivery parameters that adjust dynamically based on deliverability results.

Real-time monitoring

The Intelligence Router provides instant visibility across all data sources with real-time alerts and dynamic delivery adjustments for optimal performance.

Adaptive Delivery keeps your mail moving.

Every mailbox provider pushes back differently, throttling, deferring, or rejecting mail when you send too fast or your reputation slips. Momentum reads those signals as they happen and adjusts on its own: slowing connections to a provider that's straining, holding messages to retry later, or pausing a stream until an issue clears, then resuming. You reach the inbox by respecting each provider's limits instead of hammering them, and your team can see exactly what was throttled and why. It's the same deliverability discipline behind the hosted Bird Email API, running on infrastructure you operate.

Run it wherever you need to.

Momentum runs on your own hardware, on any major cloud, or split across both. Keep message generation in your data center for control or compliance and burst to the cloud for peak load, or move the whole operation to the cloud and back as your needs change. Because you own the deployment, there is no vendor lock-in and no rip-and-replace to get started.

Questions about Momentum MTA

What is Momentum MTA?
Momentum is our on-premises email infrastructure platform for high-volume sending, with customizable workflows, routing, and delivery parameters set through its Policy Manager. It is built to scale with your sending volume while keeping performance stable, and it supports full Unicode (SMTPUTF8) so you can send to international character sets.
What is Adaptive Delivery, and how do I monitor it?
Adaptive Delivery is Momentum's automatic traffic shaping. It watches how each mailbox provider responds to your mail and adjusts in real time: throttling, deferring, or briefly pausing a stream to protect your reputation, then ramping back up once things clear. You reach the inbox without manually babysitting send rates for every provider. The Intelligence Router shows you this happening across all your data sources, with real-time alerts whenever it makes an adjustment.
Can I run Momentum in the cloud, and is it still being developed?
Yes to both. Momentum runs on your own servers, on any major cloud, or split across the two, so you can match it to your infrastructure, cost, and compliance needs and change that mix over time. It also keeps shipping: recent releases keep it current with modern operating systems, TLS 1.3, and up-to-date security and SMTP standards, and expose message events through real-time APIs you can feed into your own reporting and automation.

Plan your Momentum deployment.

Discuss message processing, routing, capacity and operational requirements with our MTA team.

Send your requirements. Our team will follow up by email about deployment and support.

Start with one channel.
Add the others when you're ready.

A test API key is yours immediately. Production unlocks when you add a payment method and verify a sender.

Using Claude Code, Cursor, or Codex? Copy a setup prompt and your agent installs the Bird CLI and skills for you. Pick yours:

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