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🚪 lumen-app-email

Backend service for IMAP/SMTP email messaging.

What is lumen-app-email?​

conjoon/lumen-app-email is a standalone PHP🐘 application built with Lumen. It provides a backend for Email messaging according to and serves endpoints for reading, writing and sending email messages with IMAP/SMTP.

lumen-app-email has minimal footprint and is easy to install.


$ composer create-project conjoon/lumen-app-email htdocs "1.*" 

If you're looking for a pre-configured environment for running an instance of lumen-app-email, we might have just the right thing for you 👉.


lumen-app-email follows a service oriented approach. Services are easily replacable with the help of upfront DI configurations and related bindings.

Use lumen-app-email, if you...

  • need a fully functional middleware for communicating with IMAP / SMTP servers
  • want to provide webmail solutions with domain-specific sign-in to IMAP accounts
  • are looking for a distribution with minimal footprint and easy setup
  • require a headless, service oriented standalone application with your infrastructure

do not use lumen-app-email, if you...

  • are looking for a stateful, session based webmail backend
  • need baked-in caching

API Examples​

# Return a list of available MailAccounts for the requesting client
GET /MailAccounts HTTP/1.1
Content-Type: application/json
Authorization: Basic Y29uam9vbjpIZWxsb1dvcmxk
Host: hostname

# Return the envelope data of the first 50 MessageItems w/o previewText of the INBOX mailbox
# for the MailAccount identified by "gmail"
GET /MailAccounts/gmail/MailFolders/INBOX/MessageItems?start=0&limit=50&attributes=*,previewText HTTP/1.1
Content-Type: application/json
Authorization: Basic Y29uam9vbjpIZWxsb1dvcmxk
Host: hostname

# Return the email identified with the uid 4356 of the INBOX mailbox for the MailAccount identified by "gmail"
GET /MailAccounts/gmail/MailFolders/INBOX/MessageItems/4356 HTTP/1.1
Content-Type: application/json
Authorization: Basic Y29uam9vbjpIZWxsb1dvcmxk
Host: hostname


The recommended way to install lumen-app-email is by using composer create-project:

composer create-project {packageName} {targetDirectory} {version}

The following command will install an instance of lumen-app-email along with its dependencies into the directory htdocs relative to the current working directory:

$ composer create-project conjoon/lumen-app-email htdocs "1.*" 

Once composer has finished downloading and installing the project, the post-create-project-cmd will automatically invoke php artisan install, the installation script for lumen-app-email. Please refer to the subsequent documentation for further details about the configuration options available:

Available CLI commands​

One lumen-app-email was installed with composer, you can use Artisan to interact with this instance using the CLI.

Change the directory to your installation of lumen-app-email and type

$ php artisan list

to get a list of all commands available with this installation.


The following CLI commands are available for an instance of lumen-app-email:

installStarts the installation process
configure:urlConfigure URL where this instance is available
configure:apiConfigure API paths
configure:envSpecify the environment this instance runs in
configure:debugEnable or disable debug mode
copyconfigActivate pre-defined configuration templates for this instance

Configuration settings collected by the various scripts can be found in the dotenv-file .env in the root-directory of the installation. The file can also be edited manually with the key/value pairs described in this document.


Starts the installation process and queues through the commands to collect all necessary information for configuring this instance. The command can also be invoked with already installed instances of lumen-app-email.

$ php artisan install


Specify the URL of the server where this instance is located, along with the path to the installation directory of lumen-app-email.

$ php artisan configure:url
dotenv key​


  • Type: String
  • Default:


The machine's URL serving this instance is


The URI of lumen-app-email on this machine is


the value of this setting must therefore be



Specify the paths to the APIs exposed by this instance.

lumen-app-email provides an auth-Service and an email-Service. The auth-Service is required for authenticating against the IMAP/SMTP servers the email-Service will connect to.

These settings provide the base-paths to the endpoints the services expose.

This instance will consider any path-segments representing the required API-Version path appended to the path automatically.

$ php artisan configure:api
dotenv key​


  • Type: String
  • Default: rest-api-email

The path to the email-Service.


  • Type: String
  • Default: rest-imapuser

The path to the auth-Service.


lumen-app-email is available at


APP_EMAIL_PATH is configured with


Endpoints for this service can then be found at


Additionally, clients can require different versions for this API by appending a version tag to this URL as a path segment:


Omitting a version in the URL will default to the latest version of this API available.

The same applies to the APP_AUTH_PATH setting.

Refer to the Backend API documentation for all available API endpoints.


Specify the environment this instance is used in.

$ php artisan configure:env
dotenv key​


  • Type: String
  • Default: production

When using lumen-app-email other than on a local machine, set this to production. For development or staging, this value can be set to an arbitrary value for branching into different functionality for these environments, if required.

Note: This is a setting introduced by Laravel. Refer to its documentation for further information.


Enable/disable debug mode for this instance.

$ php artisan configure:debug
dotenv key​


  • Type: Boolean
  • Default: false

For local development, set this to true. In production, this should be set to false, otherwise your risking to expose sensitive information to clients.

Note: This is a setting introduced by Laravel. Refer to its documentation for further information.


Copies default configuration and saves them under a name this instance requires.

This command processes configuration files located in app/config.

copyconfig will probe existing configuration files and require user interaction before it accidentally overwrites them.

$ php artisan copyconfig

The following configuration files are affected by this command:

cors.example.phpcors.phpCross-Origin Resource Sharing configuration
imapserver.example.phpimapserver.phpConfiguration for Email servers this instance may connect to

Once the files where copied, you should adjust the settings found therein to your needs.

Configuring CORS​

lumen-app-email uses fruitcake/laravel-cors for enabling Cross-Origin Resource Sharing.

A configuration template can be found in `app/config/cors.php.example`.
Copy this file to `app/config/cors.php`, and adjust the settings to your needs. The example configuration works well with development environments, but you might want to add more strict options for production, auch as the settings for `allowed_origins` and `paths`.

php artisan copyconfig can be used for automatically copying the configuration template cors.example.php to its target destination. If you choose to manually work with the template, copy and rename it to cors.php, then adjust its entries.


The options available for the cors configuration are as follows:

OptionDescriptionDefault value
pathsYou can enable CORS for 1 or multiple paths, eg. ['api/*'] []
allowed_originsMatches the request origin. Wildcards can be used, eg. * or*['*']
allowed_origins_patternsMatches the request origin with preg_match.[]
allowed_methodsMatches the request method.['*']
allowed_headersSets the Access-Control-Allow-Headers response header.['*']
exposed_headersSets the Access-Control-Expose-Headers response header.false
max_ageSets the Access-Control-Max-Age response header.0
supports_credentialsSets the Access-Control-Allow-Credentials header.false

IMAP server configurations​

In order for users to authenticate against IMAP servers, lumen-app-email provides a template-configuration file in app/config/imapserver.php.example. In this file, you can specify an array of mail server configurations. Each entry represents a mail server to which connection may be established, for both sending and receiving messages.

Note: php artisan copyconfig can be used for automatically copying the configuration template imapserver.example.php to its target destination. If you choose to manually work with the template, copy and rename it to imapserver.php, then adjust its entries.

Entry Details​

"id" => "Google_Mail",
"inbox_type" => "IMAP",
"inbox_address" => '',
"inbox_port" => 993,
"inbox_ssl" => true,
"outbox_address" => "",
"outbox_port" => 465,
"outbox_secure" => "ssl",
"root" => ["INBOX"],
"match" => ["/\@(googlemail.)(com)$/mi"]
id:stringrequired for identifying the mail account. MUST be unique in the configuration file. Will be refered to as mailAccountId throughout rest-api-email.
IMAP Settings
inbox_type:stringthe protocol used with the server for receiving messages. Right now, only IMAP is supported.
inbox_address:string(ip-)address of the server
inbox_port:integerport that should be used with inbox_address for server communication
inbox_ssl:booleanuse encrypted communication with the server. true: use SSL for encryption, false: use no encryption
SMTP Settings
outbox_address:string(ip-)address of the server
outbox_port:integerport that should be used with outbox_address for server communication
outbox_secure:stringthe encryption protocol to use with SMTP. Can be any of ssl, tls or starttls
Account Settings
match:arraya regular expression that matches an email-address to THIS server configuration.
root:arrayan array of mailbox names that serve as root folders to display for this account. Leave the array empty if all mailboxes should be read out and send to the client.
Example for match​

Prerequisite: match is set to ["/\@(googlemail.)(com)$/mi"] A client authenticates with the username "". lumen-app-email will query through the configurations of imapserver.php and test this username against regular expression defined in match. In this example, the above regular expression matches the username (i.e. email address). The configuration where the regular expression is specified will be used for subsequent operations requested by the client.

Example for root​

A common mailbox layout of IMAP servers looks like this:


If the root-configuration is set to ["INBOX"], the following mailboxes will be returned to the client:


Multiple root entries will be considered. This is useful with Google Mail, where root mailboxes (in gmail terms: "labels") can either be [Google Mail] or [Gmail]. root should be set to ["[Google Mail]", "[Gmail]"] in this case.

Additional Resources​

The documentation of rest-api-email provides information about querying available mailboxes for an authenticated client.