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An SMTP server that makes all received mails accessible via a web interface and REST API.

Project description


sendria version sendria license sendria python compatibility Downloads say thanks!

Sendria (formerly MailTrap) is a SMTP server designed to run in your dev/test environment, that is designed to catch any email you or your application is sending, and display it in a web interface instead of sending to real world. It help you prevents sending any dev/test emails to real people, no matter what address you provide. Just point your app/email client to smtp:// and look at your emails on

Sendria is built on shoulders of:

  • MailCatcher - original idea comes of this tool by Samuel Cochran.
  • MailDump - base source code of Sendria (version pre 1.0.0), by Adrian Mönnich.

If you like this tool, just say thanks.

Icon made by Freepik from

Current stable version



  • Catch all emails and store it for display.
  • Full support for multipart messages.
  • View HTML and plain text parts of messages (if given part exists).
  • View source of email.
  • Lists attachments and allows separate downloading of parts.
  • Download original email to view in your native mail client(s).
  • Mail appears instantly if your browser supports WebSockets.
  • Optionally, send webhook on every received message.
  • Runs as a daemon in the background, optionally in foreground.
  • Keyboard navigation between messages.
  • Optionally password protected access to web interface.
  • Optionally password protected access to SMTP (SMTP AUTH).
  • It's all Python!


Sendria should work on any POSIX platform where Python is available, it means Linux, MacOS/OSX etc.

Simplest way is to use Python's built-in package system:

python3 -m pip install sendria

You can also use pipx if you don't want to mess with system packages and install Sendria in virtual environment:

pipx install sendria


Python version

Sendria is tested against Python 3.7+. Older Python versions may work, or may not.

If you want to run this software on Python 2.6+, just use MailDump.

How to use

After installing Sendria just run command:

sendria --db mails.sqlite

Now send emails through smtp://, i.e.:

echo 'From: Sendria <>\n'\
'To: You <>\n'\
'Subject: Welcome!\n\n'\
'Welcome to Sendria!' | \
  curl smtp://localhost:1025 --mail-from \
    --mail-rcpt --upload-file -

or simpler with SMTPc:

smtpc send --host localhost:1025 --from --to \
  --subject 'Welcome!' --body 'Welcome to Sendria!'

Finally, look at Sendria GUI on

If you want more details, run:

sendria --help

for more info, ie. how to protect access to gui.


Sendria offers RESTful API you can use to fetch list of messages or particular message, ie. for testing purposes.

You can use excellent httpie tool:

% http localhost:1080/api/messages/
HTTP/1.1 200 OK
Content-Length: 620
Content-Type: application/json; charset=utf-8
Date: Wed, 22 Jul 2020 20:04:46 GMT
Server: Sendria/1.0.0 (

    "code": "OK",
    "data": [
            "created_at": "2020-07-22T20:04:41",
            "id": 1,
            "peer": "",
            "recipients_envelope": [
            "recipients_message_bcc": [],
            "recipients_message_cc": [],
            "recipients_message_to": [
                "You <>"
            "sender_envelope": "",
            "sender_message": "Sendria <>",
            "size": 191,
            "source": "From: Sendria <>\nTo: You <>\nSubject: Welcome!\nX-Peer: ('', 59872)\nX-MailFrom:\nX-RcptTo:\n\nWelcome to Sendria!\n",
            "subject": "Welcome!",
            "type": "text/plain"
    "meta": {
        "pages_total": 3

There are available endpoints:

  • GET /api/messages/ - fetch list of emails. There is one query string param: page for pagination.
  • DELETE /api/messages/ - delete all emails
  • GET /api/messages/{message_id}.json - fetch email metadata
  • GET /api/messages/{message_id}.plain - fetch plain part of email
  • GET /api/messages/{message_id}.html - fetch HTML part of email
  • GET /api/messages/{message_id}.source - fetch source of email
  • GET /api/messages/{message_id}.eml - download whole email as an EML file
  • GET /api/messages/{message_id}/parts/{cid} - download particular attachment
  • DELETE /api/messages/{message_id} - delete single email


There is also available Docker image of Sendria. If you want to try, just run:

docker run -p 1025:1025 -p 1080:1080 msztolcman/sendria


I'm backend developer, not a frontend guy nor designer... If you are, and want to help, just mail me!. I think GUI should be redesigned, or at least few minor issues could be solved. Also, project requires some logo and/or icon. Again, do not hesitate to mail me if you want and can help :)

Also, if you have an idea how to enhance Sendria, please fill the ticket. Every idea, every feature request can help you, me and others!

Configure Rails

For your rails application just set in your environments/development.rb:

config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { :address => '', :port => 1025 }
config.action_mailer.raise_delivery_errors = false

Configure Django

To configure Django to work with Sendria, add the following to your projects'

    EMAIL_HOST = ''
    EMAIL_PORT = 1025
    EMAIL_USE_TLS = False

Behind nginx

If you want to hide Sendria behind nginx (ie. to terminate ssl) then you can use example config (see in addons).


To start Sendria automatically with Supervisor there is in addons example config file for this purpose.



If you like or dislike this software, please do not hesitate to tell me about this me via email (

If you find bug or have an idea to enhance this tool, please use GitHub's issues.



  • updated deps in


  • added messages pagination. One page is 100 messages. Can be browsed using buttons next to "Search" window or keyboard shortcuts: Ctrl-Shift-[Cursor Left] or Ctrl-Shift-[Cursor Right].
  • changed keyboard shortcuts: instead of Ctrl-[Cursor Up] and Ctrl-[Cursor Down] there is now Ctrl-Shift-[Cursor Up] and Ctrl-Shift-[Cursor Down].
  • allow configuring default Sendria instance using config file (see sendria --help -> --config-file).
  • some fixes after hints from linters
  • minor changes and fixes


  • auth mechanisms are now implemented in aiosmtpd (thanks Arzaroth for PR)
  • huge improvements to handling DB inserts. Now all messages are stored in an internal queue, then it's saved to the DB. It solves many problems with performance and single-threaded SQLite (thanks KathrynN for reporting)
  • fixed API response when there is no data to return (#3) ( thanks KathrynN for reporting)
  • improved logging system, now log messages has log levels, also many simplifications in logging system
  • Sendria now introduce as itself when connect through SMTP (also --smtp-ident CLI param added)
  • minor fixes and performance issues solved, updated dependencies
  • next step in cleanups and making code modern



  • rename MailTrap -> Sendria


  • complete rewrite of backend part. Sendria is using asyncio and aio-libs now:
  • using asynchronous version of libraries drastically improved performance
  • Sendria now can send a webhook about every received message
  • show in GUI information about envelope sender and recipients
  • all API requests has their own namespace now: /api
  • allow to replace name of application or url in template
  • block truncating all messages from GUI (on demand)
  • fixed issues with WebSockets, should refresh mails list and reconnect if disconnected
  • fixed issues with autobuilding assets
  • many cleanups and reformatting code
  • addons for nginx and supervisor

Backward incompatible changes:

  • all api's requests are now prefixed with /api (look at API section)
  • --htpasswd cli param is renamed to --http-auth


  • fixed issue with old call do gevent.signal
  • minimum gevent version set to 1.5.0


  • bumped dependencies - security issues (dependabot)



  • fixed encoding issues


  • better support for macOS/OSX
  • links now opens in new tab/window (added 'target="blank"')
  • show message if there is no assets generated and info how to to generate them
  • added debugs for SMTP when in debug mode
  • added support for Pipenv
  • HTML tab is default now when looking at particular message
  • converted to support Python 3.6+, drop support for lower Python versions
  • added SMTP auth support (look at pull request 28 )
  • copy from MailDump v0.5.6

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