Transactional Emails using APIs

Getting started

SMTP or API? It's your choice

You can send transactional emails with MailUp in two ways:

  • With our SMTP relay (aka SMTP+)
  • Using our APIs (details below on this page)

They provide virtually the same features. In addition, performances, scalability, the aggregation policies and the usage restrictions (i.e. do not use it for promotional emails) of the APIs are exactly the same as the ones enforced for SMTP+. In fact, the two solutions share the backend architecture and the user authorization modules.  

 The main differences are the following:

  • in case you need only the basic feature, getting started with SMTP+ is usually easier because there are a lot of "ready to use" code snippets that help you implement a SMTP client   
  • with APIs you can choose between providing the whole HTML code of the message or to refer an existing email template that may be personalized with merge tags. The  SMTP relay does not support templates instead.
  • the way you access them is different. Parameters that are specified with message headers in SMTP+, in the API are handled as fields of a JSON object that is passed to the web services. For more details about these parameters please check out the examples that are provided for SMTP+
  • with APIs you can take advantage of a set of additional methods for creating and retieving users

Best Practices

  • Message aggregation: avoid using message aggregation types that create several dozen messages per day in your MailUp admin console. 
  • CampaignCode: the new CampaignCode field is a great way to aggregate messages in a way that reduces the message count and - at the same time - provides more meaningful statistics. If you don't specify the CampaignCode value, the default value for the SMTP+ user applies (this value is set in the admin console).
  • Returned value. Always check the value returned by the API: since most of the returned errors code are due to bad input parameters, any retry attempt will fail when returned code is HTTP 403.

Sending limitations

Free trial accounts: please note that free trial accounts are limited to 25 messages sent per month.

Paying customers: once you become a paying customer, your sending speed and volume will be limited by the message frequency that you have purchased (e.g. 5,000 messages per hour). See MailUp pricing for more.

Input rate limit

The number of incoming requests must not exceed the frequency of messages you have purchased (e.g. if your MailUp subscription is set to 5,000 messages per hour avoid making more than 5,000 API calls to send messages). If you exceed this threshold, submission requests are likely to be rejected

Warnings

  • Password. If you change the password of your SMTP+ account, then any application based on it, API included, will stop working. 
  • Priority. Do not rely too much on the "Priority" field: many restrictions apply on it because its value is properly handled only at a specific stage of message workflow. There is no way to guarantee that the order based on priority value is kept at all delivery stages.
  • No API error vs. successful message delivery. Please be aware that - just like with SMTP+ - all methods used to send emails are asynchronous, hence a successful return code means that the request was correct and it has been added to a queue, but it does not guarantee immediate message delivery. In other words, a successful return code indicates that queuing and processing was successful, but the specified recipient might still be unreachable or unsubscribed.
  • Caching applies. If you enable or disable an existing user, it may take up to 15' for the changes to take effect
On this page...

 



User Management resources

Depending on the invoked method, user management resources may require different credentials and authentication methods.

Authentication typeReferencesDescription
OAuth 2Authenticating with OAuth v2

Standard OAuth 2 with access and refresh tokens. In the request you must add the following header:

Authorization: Bearer {access_token}

Note: OAuth 2 requires the MailUp account credentials, not SMTP+ username and password

SMTP+ credentials in the request bodySMTP relay service

SMTP+ username and password must be included in each request through the "User" parameter inside the request body.

"User":{"Username":"YourSmtpPlusUsername","Secret":"YourSmtpPlusPassword"}

An error may be returned when the SMTP+ user is blocked. In this case you could use the "ListUserInfo" method to get more details about that user. 

 For example, there could be a billing issue.


Create a SMTP+ user

To access resources and to use the methods, you must have an active account with an enabled SMTP+ user (SMTP+ users have the "sNNNNN_NN" name format). You can create SMTP+ accounts and retrieve their credentials:

  1. from within the MailUp platform. See: SMTP Settings
  2. calling a REST API endpoint

In this page we explain how to create a SMTP+ account using the REST API endpoint.

Get priority codes

Description

Service method to get the enumerated types of the available priority levels

AuthenticationOAuth 2

HTTP Method

GET

URL

https://services.mailup.com/api/v1.1/rest/ConsoleService.svc/Console/SmtpPlusPriorities

JSON request (example)

none

JSON response (example)

 Click here to expand...
[
    {
        "PriorityCode": 1,
        "PriorityName": "VeryHigh"
    },
    {
        "PriorityCode": 2,
        "PriorityName": "High"
    },
    {
        "PriorityCode": 3,
        "PriorityName": "Normal"
    },
    {
        "PriorityCode": 4,
        "PriorityName": "Low"
    },
    {
        "PriorityCode": 5,
        "PriorityName": "VeryLow"
    }
]



Paging and filtering (example)

none

Create a new user

Description

Before creating a SMTP+ user you have to define one or more trusted senders email and/or one or more trusted domains. To retrieve the list of trusted emails please refer to this page. Remember that you can create a SMTP+ user only if all the trusted senders you provide in the TrustedSenders field have the StatusCode property equals to 1 (Confirmed): you can find this information here.


AuthenticationOAuth 2

HTTP Method

POST

URL

https://services.mailup.com/api/v1.1/rest/ConsoleService.svc/Console/List/{id_list}/SmtpPlus

JSON request (example)

{
	"IsEnabled": true,
	"Note": "Your notes",
	"PriorityCode": 2,
	"TrustedDomains": ["yourtrusteddomain.com"],
	"TrustedSenders": ["you@yourtrusteddomain.com"]
}

JSON response (example)

 Click here to see an example of successful response...

If your request is correct, you receive the following response:

200 OK

{
    "CreationDate": "2017-06-30 10:32:38Z",
    "IdList": 2,
    "IsEnabled": true,
    "Note": "",
    "Password": "ut0ee?k9jv",
    "PriorityCode": 3,
    "SmtpPlusEncryption": "NONE, STARTTLS",
    "SmtpPlusPort": "25, 80, 1025-5000",
    "SmtpPlusServer": "in.smtpok.com",
    "TrustedDomains": [
		"yourtrusteddomain.com"
	],
    "TrustedSenders": [
        ""you@yourtrusteddomain.com""
    ],
    "UpdateDate": "2017-06-30 10:32:38Z",
    "Username": "sXXXXX_XX"
}



 Click here to check the error codes

You receive a 400 Bad request response containing the reason into the Error Description field when you try to create an account with:

  • a missing or empty request body
  • a wrong PriorityCode value (to retrieve the list of valid priority codes please refer to the Get priority codes paragraph)
  • both the fields TrustedDomains and TrustedSenders are empty
  • at least an email address not trusted into the TrustedSenders field
  • at least a domain address not trusted into the TrustedDomains field

You receive a 403 Forbidden response, containing the reason in the Error Description field, when the SMTP+ user management option is not enabled in your platform.

A HTTP 500 error is returned if the specified sender address has raised a warning in the deliverability checkup process (refer to "Account settings > Deliverability checkup")



Paging and filtering (example)

none

Reset password

Description

Reset the password for the specified SMTP+ user. MailUp is in charge of creating a new password and providing it in the response body

AuthenticationOAuth 2

HTTP Method

POST

URL

https://services.mailup.com/api/v1.1/rest/ConsoleService.svc/Console/List/{ID_LIST}/SmtpPlus/Reset

JSON request (example)

{
	"Username": "<username>"
}

JSON response (example)

200 OK

{
    "CreationDate": "2017-08-11 07:42:45Z",
    "IdList": 2,
    "IsEnabled": true,
    "IsTrusted": true,
    "Note": "My notes",
    "Password": "<the new password>",
    "PriorityCode": 3,
    "SmtpPlusEncryption": "NONE, STARTTLS",
    "SmtpPlusPort": "25, 80, 1025-5000",
    "SmtpPlusServer": "fast.smtpok.com",
    "TrustedDomains": [],
    "TrustedSenders": [
        "you@yourtrusteddomain.com"
    ],
    "UpdateDate": "2017-08-11 08:44:50Z",
    "Username": "<username>"
}


If something goes wrong:

404 NotFound

{
    "ErrorCode": "404",
    "ErrorDescription": "Account not found.",
    "ErrorName": "NotFound",
    "ErrorStack": ""
}

Paging and filtering (example)

none


Get SMTP+ users

Use ListUserInfo to retrieve status details about current SMTP+ user or other SMTP+ users that belong to the same List of a specified MailUp account.

ListUserInfo

DescriptionThis method returns the list of SMTP+ users that exist in the List of a specified MailUp account. Status details of each user are provided
AuthenticationSMTP+ credentials in the request body
HTTP MethodPOST
URLhttps://send.mailup.com/API/v2.0/users/listuserinfo 
Reference
 Click here to learn more about request parameters

The request must contain the user's credentials and an optional username to query

ListUsersDTO
ParameterTypeDescription
UserSMTPUserDTOthe calling User
UsernameStringoptional User from which to read the profile, if omitted the method returns all users

See the SendMessage reference for the definition of SMTPUserDTO

 Click here to learn more about response parameters

The response is given by a JSON or XML document that has the structure of a list of users information ( List<UserInfoDTO>). 

UserInfoDTO
ParameterTypeDescription
UsernameSMTPUserDTOthe username
IdConsolelongthe MailUp account ID
IdListlongthe List Id within that account
IsEnabledbooltrue if the user is enabled
Priorityintdefault priority setting for messages sent by this user
Notestringadmin notes
CreationDatedatetimecreation date
UpdateDatedatetimelast updated date
DomainListstringlist of allowed domains
SenderListstringlist of allowed email senders
BlockUntildatetimedate until the user is blocked
AdminBlockbooltrue if the user is blocked by the system administrator
JSON request (example)
{"User":{"Username":"sNNNN_NN","Secret":"..."},"Username":"sMMMM_MM"}
JSON response (example)Example of a successfulresponse:
{
"Status":"done",
"Code":"0",
"Message":"Ok",
"UserList":
[
{
"Username":"sMMMM_MM",
"IdConsole":123,
"IdList":1,
"IsEnabled":true,
"Priority":3,
"Note":"",
"CreationDate":"2015-03-31T12:12:04",
"UpdateDate":"2015-03-31T12:12:34",
"DomainList":"",
"SenderList":"",
"BlockUntil":"0001-01-01T00:00:00",
"AdminBlock":false
}
]
}

Example of error:
{
"Status":"error",
"Code":"112",
"Message":"User is deleted."
}

 

Send resources

All the send resources are accessed using SMTP+ credentials

 

Authentication typeReferencesDescription
SMTP+ credentials in the request bodySMTP relay service

SMTP+ Username and password must be included in each request through the "User" parameter inside the request body.

"User":{"Username":"YourSmtpPlusUsername","Secret":"YourSmtpPlusPassword"}

An error may be returned when the SMTP+ user is blocked. In this case you could use the "ListUserInfo" method to get more details about that user. 

 For example, there could be a billing issue.


Messages

This section includes the methods that can be used to send transactional emails.

Use SendMessage when you need to specify a completely different content for each message, while you can use SendTemplate - and use merge tags - if you want to pick the body of an existing content and simply customize some of its parts.

The two methods provide the same level of performance: pick the one that better fits your needs. 


Using a reply-to address different from the sender address

The use of a reply-to address different from the FROM email address must be enabled by MailUp. If you need this, please contact our support team by writing an email to support@mailup.com.

SendMessage

Description

This method allows sending of a transactional message to multiple recipients. This method is not intended for bulk mailings.

The message content is passed as input with HTML code or plain text. The message may also include attachments and embedded images.

AuthenticationSMTP+ credentials in the request body
HTTP MethodPOST
URLhttps://send.mailup.com/API/v2.0/messages/sendmessage
Reference
 Click here to learn more about request parameters

The method takes as input the document JSON or XML that has the structure MessageDTO defined in the tables below.

MessageDTO
ParameterTypeDescription
SubjectStringthe subject of the message
HtmlHtmlDTOHTML part of the message (specify only the HTML inside the BODY tag)
TextStringthe plain text part of the message
FromEmailAddressDTOthe sender's name and email address
ToList<EmailAddressDTO>the list of recipientsin Toheader
CcList<EmailAddressDTO>the list of recipients in Cc header
BccList<EmailAddressDTO>the list of recipients in Bcc
ReplyToStringthe email address to be added into Reply-To header
CharSetStringthe charset of the message body
ExtendedHeadersList<NameValueDTO>list of custom headers (only SMTP headers that are approved by MailUp will be added)
AttachmentsList<MessagePartDTO>list of attachments
EmbeddedImagesList<MessagePartDTO>list of embedded images
XSmtpAPIXSmtpAPIDTO

the X-SMTPAPI header value, used for custom aggregations and configurations.

You can use this parameter to overwrite, for a specific message, some of the settings
that are defined at SMTP+ user level

UserSmtpUserDTOthe SMTP+ user credentials: the API uses the same credentials as the SMTP relay

 

HtmlDTO
ParameterTypeDescription
DocTypeStringthe DOCTYPE directive
HeadStringthe head content
BodyStringthe body content
BodyTagStringthe body tag, default is "< body>"
EmailAddressDTO
ParameterTypeDescription
NameStringthe name
EmailStringthe email address
NameValueDTO
ParameterTypeDescription
NStringthe name of the parameter
VStringthe value of the parameter
MessagePartDTO
ParameterTypeDescription
FilenameStringthe file name
ContentIdStringthe Content-Id value
BodyArray of Bytethe array of byte of the content
XSmtpAPIDTO
ParameterTypeDescription
CampaignNameStringthe name used for the aggregated campaign
CampaignCodeStringthe campaign code which determines the aggregation
HeaderBooleanadd or not the MailUp header to the message
FooterBooleanadd or not the MailUp footer to the message
ClickTrackingBooleanenable click tracking
ViewTrackingBooleanenable view tracking
PriorityIntegerset the priority of the message (1 high - 5 low )
ScheduleDateTime

schedule date and time of when it should be sent

Time must be specified with the CET Time zone because it is compared with our servers' time settings. 

Examples:

  • "Schedule": "2021-10-06T17:35+02:00" (with Daylight Saving Time)
  • "Schedule": "2021-12-25T17:35+01:00" (without DST)

Please note that an immediate sendout is done if the specified scheduling is before the current date time

DynamicFieldsList<NameValueDTO>list of merge tags and recipient fields
CampaignReportStringname of the aggregated campaign report
SkipDynamicFieldsBooleanskip merge tags evaluation
SmtpUserDTO
ParameterTypeDescription
UsernameStringusername
SecretStringpassword



 Click here to learn more about response parameters


SendResponseDTO
ParameterTypeDescription
StatusStringthe status of the response can be "done" or "error"
CodeStringthe result code (see the Error Code table)
MessageStringthe result message

 


 JSON request (example)
 Click here to expand...
{
"Html":
{
"DocType":null,
"Head":null,
"Body":"<div>Hello Mr. [firstname] [lastname] !!!</div><br><img width=\"600\" height=\"397\" src=\"cid:img001\">",
"BodyTag":"<body>"
},
"Text":"Hello world!!!",
"Subject":"Hello friend!",
"From":{"Name":"Test User","Email":"test@mailup.it"},
"To":[{"Name":"Massimo","Email":"info@mailup.it"}],
"Cc":[],
"Bcc":[],
"ReplyTo":null,
"CharSet":"utf-8",
"ExtendedHeaders":null,
"Attachments":null,
"EmbeddedImages":
[
{
"Filename":"Image.jpg",
"ContentId":"img001",
"Body":""
}
],
"XSmtpAPI":
{
"CampaignName":"Test Campaign",
"CampaignCode":"1001",
"Header":false,
"Footer":true,
"ClickTracking":null,
"ViewTracking":null,
"Priority":null,
"Schedule":"2021-09-14T17:58+02:00",
"DynamicFields":[{"N":"firstname","V":"Mario"},{"N":"lastname","V":"Rossi"}],
"CampaignReport":null,
"SkipDynamicFields":null
},
"User":{"Username":"sNNNNN_NN","Secret":"..."}
}
JSON response (example)Example of a successful response:
{
"Status":"done",
"Code":"0",
"Message":"Ok"
}
Example of error:
{
"Status":"error",
"Code":"102",
"Message":"The operation is not authorized."
}

SendTemplate

Description

This method allows sending of a transactional message to multiple recipients, taking advantage of placeholders to customize content. This method is not intended for bulk mailings.

The message content (both HTML body and plain text) is obtained by specifying the unique ID of a message previously created and stored in the MailUp admin console.

The message may also include attachments and embedded images.

Only lowercase placeholders must be used in the referenced messages. If you use capital letters (e.g. "Dear [FirstName]", the text is not replaced.

If you edit an email message already sent, wait 15 minutes before sending out the modified message. This time is needed to update the cache

AuthenticationSMTP+ credentials in the request body
HTTP MethodPOST
URLhttps://send.mailup.com/API/v2.0/messages/sendtemplate 
Reference
 Click here to learn more about request parameters


TemplateDTO
ParameterTypeDescription
SubjectStringthe subject of the message
TemplateIdIntegerNumeric ID of the MailUp message whose content has to be used. It only accepts messages that belong to the same List in which the SMTP+ user was created
FromEmailAddressDTO

the sender's name and email address

ToList<EmailAddressDTO>the list of recipientsin Toheader
CcList<EmailAddressDTO>the list of recipients in Cc header
BccList<EmailAddressDTO>the list of recipients in Bcc
ReplyToStringthe email address to be added into Reply-To header
CharSetStringthe charset of the message body
ExtendedHeadersList<NameValueDTO>list of custom headers (only SMTP headers that are approved by MailUp will be added)
AttachmentsList<MessagePartDTO>list of attachments
EmbeddedImagesList<MessagePartDTO>list of embedded images
XSmtpAPIXSmtpAPIDTO

the X-SMTPAPI header value, used for custom aggregations and configurations

You can use this parameter to overwrite, for a specific message, some of the settings
that are defined at SMTP+ user level

UserSmtpUserDTOthe SMTP+ user credentials

 See the SendMessage reference for the definition of the others DTOs (EmailAddressDTO, NameValueDTO, ...)

 Click here to learn more about response parameters


SendResponseDTO
ParameterTypeDescription
StatusStringthe status of the response can be "done" or "error"
CodeStringthe result code (see the Error Code table)
MessageStringthe result message

 

JSON request (example)
 Click here to expand...
{
"TemplateId":694,
"Subject":"Test message from template",
"From":{"Name":"Test User","Email":"test@example.com"},
 "To":[{"Name":"Max","Email":"info@example.com"}],
"Cc":[],
"Bcc":[],
"ReplyTo":null,
"CharSet":"utf-8",
"ExtendedHeaders":null,
"Attachments":null,
"EmbeddedImages":null,
"XSmtpAPI":null,
"User":{"Username":"sNNNNN_NN","Secret":"..."}
}
JSON response (example)Example of a successfulresponse:
{
"Status":"done",
"Code":"0",
"Message":"Ok"
}

Example of error:
{
"Status":"error",
"Code":"111",
"Message":"The template is not found."
}

 

Error codes

This table lists the response codes that can be returned by the API methods whose authentication method consists of SMTP+ credentials in the request body.


HTTP response code
Application Code
Description
2000Ok
4001The operation failed.
403101The input is null.
403102The operation is not authorized.
403103The user is not enabled.
403104The user is blocked.
403105The user is blocked until this date.
403106The MailUp account cannot be found.
403107The MailUp account has been suspended.
403108The MailUp account has been deleted.
403109At least one recipient is required.
403110The sender is required.
403111The template cannot found.
403112The user has been deleted.