Send email with Postmark through Courier

Prerequisites

A Postmark account with a verified sender signature
Your Postmark Server API Token

Setup

Get your Postmark server token

In Postmark, open the server you send from and copy its Server API token.

Configure in Courier

Open the in Courier, enter your API token and From Address, then save.

Addressing a recipient and sending are the same on every email provider, so they are documented once: and .

Subject character limit

The Postmark API limits subject lines to ~60 characters. Emojis and special characters lower that limit because of encoding.

Overrides

covers the two levels and which one wins. lists the fields every email provider takes. A provider override changes what Courier sends to Postmark’s Email API. This example adds a MessageStream and an attachment:

const { requestId } = await courier.send.message({
  message: {
    template: "nt_01kx4h2jdafq8bk9aftxak4b40",
    to: {
      email: "sarah@acme-corp.com",
    },
    providers: {
      postmark: {
        override: {
          config: {
            MessageStream: "message_stream_id",
          },
          body: {
            Attachments: [
              {
                Name: "readme.txt",
                Content: "dGVzdCBjb250ZW50",
                ContentType: "text/plain",
              },
            ],
          },
        },
      },
    },
  },
});

response = client.send.message(
    message={
        "template": "nt_01kx4h2jdafq8bk9aftxak4b40",
        "to": {
            "email": "sarah@acme-corp.com",
        },
        "providers": {
            "postmark": {
                "override": {
                    "config": {
                        "MessageStream": "message_stream_id",
                    },
                    "body": {
                        "Attachments": [
                            {
                                "Name": "readme.txt",
                                "Content": "dGVzdCBjb250ZW50",
                                "ContentType": "text/plain",
                            },
                        ],
                    },
                },
            },
        },
    },
)

curl -X POST https://api.courier.com/send \
  -H "Authorization: Bearer $COURIER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "message": {
      "template": "nt_01kx4h2jdafq8bk9aftxak4b40",
      "to": {
        "email": "sarah@acme-corp.com"
      },
      "providers": {
        "postmark": {
          "override": {
            "config": {
              "MessageStream": "message_stream_id"
            },
            "body": {
              "Attachments": [
                {
                  "Name": "readme.txt",
                  "Content": "dGVzdCBjb250ZW50",
                  "ContentType": "text/plain"
                }
              ]
            }
          }
        }
      }
    }
  }'

response = courier.send_.message(
  message: {
    template: "nt_01kx4h2jdafq8bk9aftxak4b40",
    to: {
      email: "sarah@acme-corp.com"
    },
    providers: {
      postmark: {
        override: {
          config: {
            MessageStream: "message_stream_id"
          },
          body: {
            Attachments: [
              {
                Name: "readme.txt",
                Content: "dGVzdCBjb250ZW50",
                ContentType: "text/plain"
              }
            ]
          }
        }
      }
    }
  }
)

response, err := client.Send.Message(context.TODO(), courier.SendMessageParams{
	Message: courier.SendMessageParamsMessage{
		To: courier.SendMessageParamsMessageToUnion{
			OfUserRecipient: &shared.UserRecipientParam{
				Email: courier.String("sarah@acme-corp.com"),
			},
		},
		Template: courier.String("nt_01kx4h2jdafq8bk9aftxak4b40"),
		Providers: shared.MessageProvidersParam{
			"postmark": shared.MessageProvidersTypeParam{
				Override: map[string]any{
					"config": map[string]any{
						"MessageStream": "message_stream_id",
					},
					"body": map[string]any{
						"Attachments": []any{
							map[string]any{
								"Name": "readme.txt",
								"Content": "dGVzdCBjb250ZW50",
								"ContentType": "text/plain",
							},
						},
					},
				},
			},
		},
	},
})

SendMessageParams params = SendMessageParams.builder()
    .message(SendMessageParams.Message.builder()
        .to(UserRecipient.builder().email("sarah@acme-corp.com").build())
        .template("nt_01kx4h2jdafq8bk9aftxak4b40")
        .providers(MessageProviders.builder()
            .putAdditionalProperty("postmark", JsonValue.from(java.util.Map.of("override", java.util.Map.of(
                    "config", java.util.Map.of(
                        "MessageStream", "message_stream_id"
                    ),
                    "body", java.util.Map.of(
                        "Attachments", java.util.List.of(
                            java.util.Map.of(
                                "Name", "readme.txt",
                                "Content", "dGVzdCBjb250ZW50",
                                "ContentType", "text/plain"
                            )
                        )
                    )
                ))))
            .build())
        .build())
    .build();
SendMessageResponse response = client.send().message(params);

$response = $client->send->message(
  message: [
    'template' => 'nt_01kx4h2jdafq8bk9aftxak4b40',
    'to' => [
      'email' => 'sarah@acme-corp.com',
    ],
    'providers' => [
      'postmark' => [
        'override' => [
          'config' => [
            'MessageStream' => 'message_stream_id',
          ],
          'body' => [
            'Attachments' => [
              [
                'Name' => 'readme.txt',
                'Content' => 'dGVzdCBjb250ZW50',
                'ContentType' => 'text/plain',
              ],
            ],
          ],
        ],
      ],
    ],
  ],
);

SendMessageParams parameters = new()
{
    Message = new()
    {
        To = new UserRecipient { Email = "sarah@acme-corp.com" },
        Template = "nt_01kx4h2jdafq8bk9aftxak4b40",
        Providers = new Dictionary<string, MessageProvidersType>()
        {
            {
                "postmark",
                new()
                {
                    Override = JsonSerializer.Deserialize<Dictionary<string, JsonElement>>(
                        """
                        {
                          "config": {
                            "MessageStream": "message_stream_id"
                          },
                          "body": {
                            "Attachments": [
                              {
                                "Name": "readme.txt",
                                "Content": "dGVzdCBjb250ZW50",
                                "ContentType": "text/plain"
                              }
                            ]
                          }
                        }
                        """
                    ),
                }
            },
        },
    },
};

var response = await client.Send.Message(parameters);

courier send message \
  --api-key "$COURIER_API_KEY" \
  --message.to '{"email": "sarah@acme-corp.com"}' \
  --message.template nt_01kx4h2jdafq8bk9aftxak4b40 \
  --message.providers '{"postmark": {"override": {"config": {"MessageStream": "message_stream_id"}, "body": {"Attachments": [{"Name": "readme.txt", "Content": "dGVzdCBjb250ZW50", "ContentType": "text/plain"}]}}}}'

With Courier MCP, send my template to sarah@acme-corp.com on my Postmark broadcast message stream.

Overrides are deep-merged into the request. Fields you set replace their counterparts, and everything you leave out is still sent. For every option, see the Postmark API docs. override.config.fromAddress swaps the sender for one message, in place of the From Address saved on the integration. A template From value or a channels.email.override.from still wins over it. covers the order.

Using Postmark templates

const { requestId } = await courier.send.message({
  message: {
    to: {
      email: "sarah@acme-corp.com",
    },
    template: "nt_01kx4h2jdafq8bk9aftxak4b40",
    providers: {
      postmark: {
        override: {
          config: {
            url: "https://api.postmarkapp.com/email/withTemplate",
          },
          body: {
            TemplateId: "123456",
            TemplateModel: {
              product_url: "product_url_Value",
              product_name: "product_name_Value",
              name: "name_Value",
              action_url: "action_url_Value",
              login_url: "login_url_Value",
              username: "username_Value",
              trial_length: "trial_length_Value",
              trial_start_date: "trial_start_date_Value",
              trial_end_date: "trial_end_date_Value",
              support_email: "support_email_Value",
              live_chat_url: "live_chat_url_Value",
              sender_name: "sender_name_Value",
              help_url: "help_url_Value",
              company_name: "company_name_Value",
              company_address: "company_address_Value",
            },
          },
        },
      },
    },
  },
});

response = client.send.message(
    message={
        "to": {
            "email": "sarah@acme-corp.com",
        },
        "template": "nt_01kx4h2jdafq8bk9aftxak4b40",
        "providers": {
            "postmark": {
                "override": {
                    "config": {
                        "url": "https://api.postmarkapp.com/email/withTemplate",
                    },
                    "body": {
                        "TemplateId": "123456",
                        "TemplateModel": {
                            "product_url": "product_url_Value",
                            "product_name": "product_name_Value",
                            "name": "name_Value",
                            "action_url": "action_url_Value",
                            "login_url": "login_url_Value",
                            "username": "username_Value",
                            "trial_length": "trial_length_Value",
                            "trial_start_date": "trial_start_date_Value",
                            "trial_end_date": "trial_end_date_Value",
                            "support_email": "support_email_Value",
                            "live_chat_url": "live_chat_url_Value",
                            "sender_name": "sender_name_Value",
                            "help_url": "help_url_Value",
                            "company_name": "company_name_Value",
                            "company_address": "company_address_Value",
                        },
                    },
                },
            },
        },
    },
)

curl -X POST https://api.courier.com/send \
  -H "Authorization: Bearer $COURIER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "message": {
      "to": {
        "email": "sarah@acme-corp.com"
      },
      "template": "nt_01kx4h2jdafq8bk9aftxak4b40",
      "providers": {
        "postmark": {
          "override": {
            "config": {
              "url": "https://api.postmarkapp.com/email/withTemplate"
            },
            "body": {
              "TemplateId": "123456",
              "TemplateModel": {
                "product_url": "product_url_Value",
                "product_name": "product_name_Value",
                "name": "name_Value",
                "action_url": "action_url_Value",
                "login_url": "login_url_Value",
                "username": "username_Value",
                "trial_length": "trial_length_Value",
                "trial_start_date": "trial_start_date_Value",
                "trial_end_date": "trial_end_date_Value",
                "support_email": "support_email_Value",
                "live_chat_url": "live_chat_url_Value",
                "sender_name": "sender_name_Value",
                "help_url": "help_url_Value",
                "company_name": "company_name_Value",
                "company_address": "company_address_Value"
              }
            }
          }
        }
      }
    }
  }'

response = courier.send_.message(
  message: {
    to: {
      email: "sarah@acme-corp.com"
    },
    template: "nt_01kx4h2jdafq8bk9aftxak4b40",
    providers: {
      postmark: {
        override: {
          config: {
            url: "https://api.postmarkapp.com/email/withTemplate"
          },
          body: {
            TemplateId: "123456",
            TemplateModel: {
              product_url: "product_url_Value",
              product_name: "product_name_Value",
              name: "name_Value",
              action_url: "action_url_Value",
              login_url: "login_url_Value",
              username: "username_Value",
              trial_length: "trial_length_Value",
              trial_start_date: "trial_start_date_Value",
              trial_end_date: "trial_end_date_Value",
              support_email: "support_email_Value",
              live_chat_url: "live_chat_url_Value",
              sender_name: "sender_name_Value",
              help_url: "help_url_Value",
              company_name: "company_name_Value",
              company_address: "company_address_Value"
            }
          }
        }
      }
    }
  }
)

response, err := client.Send.Message(context.TODO(), courier.SendMessageParams{
	Message: courier.SendMessageParamsMessage{
		To: courier.SendMessageParamsMessageToUnion{
			OfUserRecipient: &shared.UserRecipientParam{
				Email: courier.String("sarah@acme-corp.com"),
			},
		},
		Template: courier.String("nt_01kx4h2jdafq8bk9aftxak4b40"),
		Providers: shared.MessageProvidersParam{
			"postmark": shared.MessageProvidersTypeParam{
				Override: map[string]any{
					"config": map[string]any{
						"url": "https://api.postmarkapp.com/email/withTemplate",
					},
					"body": map[string]any{
						"TemplateId": "123456",
						"TemplateModel": map[string]any{
							"product_url": "product_url_Value",
							"product_name": "product_name_Value",
							"name": "name_Value",
							"action_url": "action_url_Value",
							"login_url": "login_url_Value",
							"username": "username_Value",
							"trial_length": "trial_length_Value",
							"trial_start_date": "trial_start_date_Value",
							"trial_end_date": "trial_end_date_Value",
							"support_email": "support_email_Value",
							"live_chat_url": "live_chat_url_Value",
							"sender_name": "sender_name_Value",
							"help_url": "help_url_Value",
							"company_name": "company_name_Value",
							"company_address": "company_address_Value",
						},
					},
				},
			},
		},
	},
})

SendMessageParams params = SendMessageParams.builder()
    .message(SendMessageParams.Message.builder()
        .to(UserRecipient.builder().email("sarah@acme-corp.com").build())
        .template("nt_01kx4h2jdafq8bk9aftxak4b40")
        .providers(MessageProviders.builder()
            .putAdditionalProperty("postmark", JsonValue.from(java.util.Map.of("override", java.util.Map.of(
                    "config", java.util.Map.of(
                        "url", "https://api.postmarkapp.com/email/withTemplate"
                    ),
                    "body", java.util.Map.of(
                        "TemplateId", "123456",
                        "TemplateModel", java.util.Map.of(
                            "product_url", "product_url_Value",
                            "product_name", "product_name_Value",
                            "name", "name_Value",
                            "action_url", "action_url_Value",
                            "login_url", "login_url_Value",
                            "username", "username_Value",
                            "trial_length", "trial_length_Value",
                            "trial_start_date", "trial_start_date_Value",
                            "trial_end_date", "trial_end_date_Value",
                            "support_email", "support_email_Value",
                            "live_chat_url", "live_chat_url_Value",
                            "sender_name", "sender_name_Value",
                            "help_url", "help_url_Value",
                            "company_name", "company_name_Value",
                            "company_address", "company_address_Value"
                        )
                    )
                ))))
            .build())
        .build())
    .build();
SendMessageResponse response = client.send().message(params);

$response = $client->send->message(
  message: [
    'to' => [
      'email' => 'sarah@acme-corp.com',
    ],
    'template' => 'nt_01kx4h2jdafq8bk9aftxak4b40',
    'providers' => [
      'postmark' => [
        'override' => [
          'config' => [
            'url' => 'https://api.postmarkapp.com/email/withTemplate',
          ],
          'body' => [
            'TemplateId' => '123456',
            'TemplateModel' => [
              'product_url' => 'product_url_Value',
              'product_name' => 'product_name_Value',
              'name' => 'name_Value',
              'action_url' => 'action_url_Value',
              'login_url' => 'login_url_Value',
              'username' => 'username_Value',
              'trial_length' => 'trial_length_Value',
              'trial_start_date' => 'trial_start_date_Value',
              'trial_end_date' => 'trial_end_date_Value',
              'support_email' => 'support_email_Value',
              'live_chat_url' => 'live_chat_url_Value',
              'sender_name' => 'sender_name_Value',
              'help_url' => 'help_url_Value',
              'company_name' => 'company_name_Value',
              'company_address' => 'company_address_Value',
            ],
          ],
        ],
      ],
    ],
  ],
);

SendMessageParams parameters = new()
{
    Message = new()
    {
        To = new UserRecipient { Email = "sarah@acme-corp.com" },
        Template = "nt_01kx4h2jdafq8bk9aftxak4b40",
        Providers = new Dictionary<string, MessageProvidersType>()
        {
            {
                "postmark",
                new()
                {
                    Override = JsonSerializer.Deserialize<Dictionary<string, JsonElement>>(
                        """
                        {
                          "config": {
                            "url": "https://api.postmarkapp.com/email/withTemplate"
                          },
                          "body": {
                            "TemplateId": "123456",
                            "TemplateModel": {
                              "product_url": "product_url_Value",
                              "product_name": "product_name_Value",
                              "name": "name_Value",
                              "action_url": "action_url_Value",
                              "login_url": "login_url_Value",
                              "username": "username_Value",
                              "trial_length": "trial_length_Value",
                              "trial_start_date": "trial_start_date_Value",
                              "trial_end_date": "trial_end_date_Value",
                              "support_email": "support_email_Value",
                              "live_chat_url": "live_chat_url_Value",
                              "sender_name": "sender_name_Value",
                              "help_url": "help_url_Value",
                              "company_name": "company_name_Value",
                              "company_address": "company_address_Value"
                            }
                          }
                        }
                        """
                    ),
                }
            },
        },
    },
};

var response = await client.Send.Message(parameters);

courier send message \
  --api-key "$COURIER_API_KEY" \
  --message.to '{"email": "sarah@acme-corp.com"}' \
  --message.template nt_01kx4h2jdafq8bk9aftxak4b40 \
  --message.providers '{"postmark": {"override": {"config": {"url": "https://api.postmarkapp.com/email/withTemplate"}, "body": {"TemplateId": "123456", "TemplateModel": {"product_url": "product_url_Value", "product_name": "product_name_Value", "name": "name_Value", "action_url": "action_url_Value", "login_url": "login_url_Value", "username": "username_Value", "trial_length": "trial_length_Value", "trial_start_date": "trial_start_date_Value", "trial_end_date": "trial_end_date_Value", "support_email": "support_email_Value", "live_chat_url": "live_chat_url_Value", "sender_name": "sender_name_Value", "help_url": "help_url_Value", "company_name": "company_name_Value", "company_address": "company_address_Value"}}}}}'

With Courier MCP, send my template to sarah@acme-corp.com and render it with a Postmark template.

The message.providers.postmark.override.config property replaces Courier templates with Postmark’s Templates API. Include the https://api.postmarkapp.com/email/withTemplate URL in the config object, and TemplateId and TemplateModel in the body.

With Postmark templates, your request must use a template parameter, not content. Otherwise content takes precedence over the Postmark override. An invalid template_id causes an error.

Provider details

postmark

Courier recommends routing to the channel. Naming this key in routing.channels instead is supported, and sends through just this provider.

Send to a specific provider

When that is worth doing, and what you give up: failover, channel priority, and providers you add later.

Get started

Available integrations

Send email with Postmark through Courier

Prerequisites

Setup

Subject character limit

Overrides

Using Postmark templates

Provider details

Send to a specific provider

​Prerequisites

​Setup

​Subject character limit

​Overrides

​Using Postmark templates

​Provider details

Send to a specific provider

Prerequisites

Setup

Subject character limit

Overrides

Using Postmark templates

Provider details