> For the complete documentation index, see [llms.txt](https://docs.emaildelivery.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.emaildelivery.com/docs/what-you-need-to-know-before-you-install-velocity-mta/how-to-use-velocity-mta-as-an-smtp-relay.md).

# How to use Velocity MTA as an SMTP Relay

All email sent through the ESP platform must originate with a Customer Account, including mail sent using Velocity MTA. 

You can't connect to the MTA directly and use SMTP Relay while going outside of the ESP platform. 

To use SMTP Relay with Velocity MTA, you must add the MTA to a Postal Route, give a Customer Account access to that Postal Route, and then use SMTP Relay through that Customer Account. 

SMTP Relay application -> Velocity MTA <mark style="color:red;">❌</mark>

SMTP Relay application -> Customer Account -> Postal Route -> Velocity MTA ✅

See instructions on using SMTP Relay with Velocity MTA below:

{% content-ref url="/pages/Zb1Y4kmTg6ZSamRV89En" %}
[Transactional SMTP Relay: steps to start sending](/docs/transactional/transactional-smtp-relay-steps-to-start-sending.md)
{% endcontent-ref %}

{% content-ref url="/pages/9dicqeeYH5F8cv0kteiM" %}
[Transactional SMTP Relay](/docs/transactional/transactional-smtp-relay.md)
{% endcontent-ref %}