Unfortunately an automated installer is not yet available for Windows systems. To perform a manual installation in Windows, follow these steps:

  • Download the template configuration and uncompress it as <BASE_PATH>.
  • Edit <BASE_PATH>/etc/config.toml and replace all occurrences of the following strings:
    • __HOST__ with your SMTP server’s fully-qualified domain name, for example “”.
    • __DOMAIN__ with your main domain name, for example “”.
    • __ADMIN_PASS__ with the administrator password to use to manage Stalwart SMTP.
    • __LMTP_HOST__ and __LMTP_PORT__ with the address and port to use to deliver messages to your message store (e.g.: Stalwart JMAP, Dovecot, Courier-IMAP, etc.) over the LMTP protocol.

Note: At the moment only x86 binaries are distributed but an ARM64 Windows version can be compiled from the sources.

Setting up

Before your Stalwart SMTP server can start accepting connections from other hosts, you’ll have to configure your hostname and install valid a TLS certificate.


Stalwart SMTP requires a valid TLS certificate in order to operate. If you currently don’t have a TLS certificate, you can obtain one for free from Let’s Encrypt. Once you have your certificate ready, copy your certificate and private key to their default locations as follows:

copy mycert.crt C:\Program Files\Stalwart SMTP\etc\certs\tls.crt
copy mykey.key C:\Program Files\Stalwart SMTP\etc\private\tls.key


DomainKeys Identified Mail (DKIM) is a method of email authentication that allows a receiving email server to verify that an email message was actually sent by the owner of the domain from which it appears to have been sent. It is highly recommended that you enable DKIM (as well as SPF and DMARC) for your domain. Please refer to the DKIM section for instructions on how to add a new DKIM signature.

Start service

To run Stalwart SMTP as a service, follow these instructions:

  • Download the NSSM service manager.
  • Run in your terminal:
    nssm install Stalwart_SMTP
  • Once the NSSM GUI appears, configure the service using the following parameters:
    Path: C:\Program Files\Stalwart SMTP\bin\stalwart-jmap.exe
    Startup directory: C:\Program Files\Stalwart SMTP
    Arguments: --config=C:\Program Files\Stalwart SMTP\etc\config.toml
  • Click on the Install Service button.

If everything is correct, you should now be able to connect to Stalwart SMTP on ports 25, 587 and 465

Next steps

Now that you have Stalwart SMTP up and running, you may want to enable SASL authentication using your IMAP4 server or SQL database.