Email and SMS Testing API

Overview

The Mailosaur API lets you test email using a simple REST API. You can make the API calls yourself, however because email and SMS messages can take time to arrive, we highly recommend using one of our official clients.

Popular Setups

Authentication

The Mailosaur API uses API keys to authenticate requests.

Authentication to the API is performed via HTTP Basic Auth. Your API key must be provided as the basic auth username value. You do not need to provide a password.

Your API keys carry many privileges, so always keep them secret and secure! Never share your API key in publicly-accessible areas such GitHub, client-side code, etc.

All API requests must be made over HTTPS. Calls made over plain HTTP will fail. API requests without authentication will also fail.

curl https://mailosaur.com/api/servers \
  -u YOUR_API_KEY:

Managing API keys

You can manage all your API keys in the Mailosaur Dashboard.

Errors

HTTP Status Codes

Mailosaur uses conventional HTTP response codes to indicate the success or failure of an API request. In general, codes in the 2xx range indicate success, codes in the 4xx range indicate an error that failed given the information provided (e.g., a required parameter was omitted), and codes in the 5xx range indicate an error with Mailosaur’s servers (give us a shout in the unlikely event that you see one of those).

Error handling

In case of an error the server will return as much information as possible. In the case of a 401 or 404 error the status code gives as much information as you’d need. But for 400 errors Mailosaur will return a JSON object containing the structure below.

Note that our client libraries convert responses to appropriate language-specific objects.

Message object

Message objects represent an email or SMS received by Mailosaur and contain all the data you might need to perform any number of manual or automated tests.

{
  "id": "77061c9f-da47-4009-9f33-9715a3bbf00c",
  "received": "2019-08-06T17:44:07.197781+00:00",
  "subject": "Email subject line",
  "from": [{
    "name": "Acme",
    "email": "noreply@example.com"
  }],
  "to": [{
    "name": "Jane Doe",
    "email": "janedoe@abc1234.mailosaur.net"
  }],
  "cc": [],
  "bcc": [],
  "html": {
    "links": [{
      "href": "https://example.com/signup",
      "text": "Sign Up Now"
    }],
    "images": [],
    "body": "Lorem ipsum..."
  },
  "text": {
    "links": [{
      "href": "https://example.com/signup",
      "text": "https://example.com/signup"
    }],
    "body": "Lorem ipsum..."
  },
  "attachments": [],
  "metadata": {
    "headers": [{
      "field": "MIME-Version",
      "value": "1.0"
    }]
  },
  "server": "abcd1234"
}

Message summaries

When performing list or search queries, a truncated summary of each message is returned instead of the full object:

{
  "id": "77061c9f-da47-4009-9f33-9715a3bbf00c",
  "received": "2019-08-06T17:44:07.197781+00:00",
  "subject": "Email subject line",
  "from": [{
    "name": "Acme",
    "email": "noreply@example.com"
  }],
  "to": [{
    "name": "Jane Doe",
    "email": "janedoe@abc1234.mailosaur.net"
  }],
  "cc": [],
  "bcc": []
}

Attributes

Messages

Retrieve a message

Retrieves the detail for a single message. Simply supply the unique identifier for the required message.

Parameters

To get the ID of a message you need to call one of our other API calls which returns a list of messages. Each message in the list will contain an ID which you can use to make this call.

Response

Status: 200 OK

// Message object

Delete a message

Permanently deletes a message. This operation cannot be undone. Also deletes any attachments related to the message.

Parameters

Response

Status: 204 No Content

List all messages

Returns a list of your messages in summary form. The summaries are returned sorted by received date, with the most recently-received messages appearing first.

Parameters

Response

Status: 200 OK

// Array of Message object

Delete all messages

Permanently deletes all messages held by the specified server. This operation cannot be undone. Also deletes any attachments related to each message.

Parameters

Response

Status: 204 No Content

Search for messages

Returns a list of message summaries matching the specified search criteria, in summary form. The summaries are returned sorted by received date, with the most recently-received messages appearing first.

Parameters

Request

Message Summaries To get the full message content, including HTML & Text body content, you need to use the Retrieve a message endpoint. Alternatively you can search and retrieve in a single call by using our official client libraries.

{
  "sentFrom": "noreply@example.com",
  "sentTo": "someone@abcd1234.mailosaur.net",
  "subject": "Email address",
  "body": "Hey Alice,",
  "match": "ALL"
}

Response

Status: 200 OK

{
  "items": [
    // Message summary object
  ]
}

Forward a message

Forward an email or SMS message to a verified external email address. Supply the unique identifier for message you want to forward, as well as additional, relevant options.

Parameters

To get the ID of a message you need to call one of our other API calls which returns a list of messages. Each message in the list will contain an ID which you can use to make this call.

Request

{
  "to": "someone@example.com",
  "html": "<p>Hello world.</p>",
  "text": "Hello world."
}

Response

Status: 200 OK

// Message object

Reply to a message

Reply to an email or SMS message. Supply the unique identifier for message you want to forward, as well as additional, relevant options.

Email replies can only be sent back to verified external email addresses. SMS replies can only contain approved phrases to prevent fraud.

Parameters

To get the ID of a message you need to call one of our other API calls which returns a list of messages. Each message in the list will contain an ID which you can use to make this call.

Request

{
  "html": "<p>Hello world.</p>",
  "text": "Hello world.",
  "attachments": [{
    "fileName": "cat.png",
    "content": "{BASE64_ENCODED_FILE}",
    "contentType": "image/png"
  }]
}

Response

Status: 200 OK

// Message object

Send an email

You can only send emails to verified external email addresses. Supply the unique identifier for server you want to send from, as well as additional, relevant options.

Parameters

Request

{
  "from": "anything@SERVER_ID.mailosaur.net",
  "to": "someone@example.com",
  "html": "<p>Hello world.</p>",
  "text": "Hello world.",
  "send": true,
  "attachments": [{
    "fileName": "cat.png",
    "content": "{BASE64_ENCODED_FILE}",
    "contentType": "image/png"
  }]
}

Response

Status: 200 OK

// Message object

Files

Download an attachment

Downloads a single attachment. Simply supply the unique identifier for the required attachment.

Parameters

Response

Status: 200 OK

<< FileStream >>

Download EML

Downloads an EML file representing the specified email. Simply supply the unique identifier for the required email.

Parameters

Response

Status: 200 OK

<< FileStream >>

Spam

Perform a spam test

Perform spam testing on the specified email.

Parameters

Response

Status: 200 OK

{
  "spamFilterResults": {
  "spamAssassin": [
    {
      "score": 0,
      "rule": "ABC123",
      "description": "ABC123"
    }
  ]},
  "score": 0
}

Servers

List all servers

Returns a list of your virtual SMTP servers. Servers are returned sorted in alphabetical order.

Response

Status: 200 OK

[
  {
    "id": "abcd1234",
    "name": "Server name",
    "users": [],
    "messages": 16
  }
]

Create a server

Creates a new virtual SMTP server and returns it.

Request

{
  "name": "My server"
}

Response

Status: 200 OK

{
    "id": "abcd1234",
    "name": "Server name",
    "users": [],
    "messages": 0
}

Retrieve a server

Retrieves the detail for a single server. Simply supply the unique identifier for the required server.

Parameters

Response

Status: 200 OK

{
    "id": "abcd1234",
    "name": "Server name",
    "users": [],
    "messages": 0
}

Retrieve server password

Retrieves the password, for use with SMTP and POP3, for a single server. Simply supply the unique identifier for the required server.

Parameters

Response

Status: 200 OK

{
    "value": "server-password"
}

Update a server

Updates a single server and returns it.

Parameters

Request

{
    "id": "abcd1234",
    "name": "Server name",
    "users": [],
    "messages": 0
}

Response

Status: 200 OK

{
    "id": "abcd1234",
    "name": "Server name",
    "users": [],
    "messages": 0
}

Delete a server

Permanently deletes a server. This operation cannot be undone. Also deletes all messages and associated attachments within the server.

Parameters

Response

Status: 204 No Content

Virtual Security Devices

Retrieve one-time password

Retrieves the one-time password for a given base32-encoded secret.

Request

{
  "sharedSecret": "ONSWG4TFOQYTEMY="
}

Response

Status: 200 OK

{
    "code": "123456",
    "expires": "2022-01-01T00:00:00Z"
}

List all devices

Returns a list of your virtual security devices.

Response

Status: 200 OK

[
  {
    "id": "abcd1234",
    "name": "Device name"
  }
]

Create a device

Creates a new virtual security device and returns it.

Request

{
  "name": "My device",
  "sharedSecret": "ONSWG4TFOQYTEMY="
}

Response

Status: 200 OK

{
    "id": "abcd1234",
    "name": "My device"
}

Retrieve OTP for an existing device

Retrieves the current one-time password for an existing virtual security device. Simply supply the unique identifier for the required device.

Parameters

Response

Status: 200 OK

{
    "code": "123456",
    "expires": "2022-01-01T00:00:00Z"
}

Delete a device

Permanently deletes a device. This operation cannot be undone.

Parameters

Response

Status: 204 No Content

Usage

Retrieve account limits

Retrieve account usage limits. Details the current limits and usage for your account. This endpoint requires authentication with an account-level API key.

Response

Status: 200 OK

{
  "servers": {
    "current": 27,
    "limit": 50
  },
  "users": {
    "current": 16,
    "limit": 25
  },
  "email": {
    "current": 12356,
    "limit": 20000
  },
  "sms": {
    "current": 271,
    "limit": 500
  },
  "previews": {
    "current": 89,
    "limit": 200
  },
  "numbers": {
    "current": 2,
    "limit": 5
  }
}

List usage transactions

Retrieves the last 31 days of transactional usage. This endpoint requires authentication with an account-level API key.

Response

Status: 200 OK

{
  "items": [
    {
      "timestamp": "2021-01-31T00:00:00Z",
      "email": 2000,
      "sms": 51,
      "previews": 0
    }
  ]
}