1.3 KiB


Based on the aiosmtpd, this packages offers you a simple way to integrate a SMTP server into your test code.

Currently, the server does not support authentication, TLS or anything special instead of sending mails.

All mails are collected in the messages property of the mock and can be evaluated there.

Looking for a pytest SMTP mock fixture? Take a look at this project:


Installation with "pip"

pip install smtp-test-server

Installation with "poetry"

poetry add --group dev smtp-test-server


Simple usage, with auto assigning a free port number on

from smtp_test_server.context import SmtpMockServer

def test_send_mail():
    with SmtpMockServer() as smtp_mock:
        my_mail_method(, smtp_port=smtp_mock.port)
    assert len(smtp_mock.messages) == 1
    assert smtp_mock.messages[0]["from"] == ""

Want to have more control over host and port? Use it like this:

with SmtpMockServer(bind_host="", bind_port=2525):

Ports are automatically closed when leaving the context.