diff --git a/cmd/tx.go b/cmd/tx.go
index 757a4ad..cb27900 100644
--- a/cmd/tx.go
+++ b/cmd/tx.go
@@ -1,12 +1,15 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"net/textproto"
 	"strings"
 
 	"github.com/knadh/listmonk/internal/manager"
+	"github.com/knadh/listmonk/internal/messenger"
 	"github.com/knadh/listmonk/models"
 	"github.com/labstack/echo/v4"
 )
@@ -18,7 +21,48 @@ func handleSendTxMessage(c echo.Context) error {
 		m   models.TxMessage
 	)
 
-	if err := c.Bind(&m); err != nil {
+	// If it's a multipart form, there may be file attachments.
+	if strings.HasPrefix(c.Request().Header.Get("Content-Type"), "multipart/form-data") {
+		form, err := c.MultipartForm()
+		if err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				app.i18n.Ts("globals.messages.invalidFields", "name", err.Error()))
+		}
+
+		data, ok := form.Value["data"]
+		if !ok || len(data) != 1 {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				app.i18n.Ts("globals.messages.invalidFields", "name", "data"))
+		}
+
+		// Parse the JSON data.
+		if err := json.Unmarshal([]byte(data[0]), &m); err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest,
+				app.i18n.Ts("globals.messages.invalidFields", "name", fmt.Sprintf("data: %s", err.Error())))
+		}
+
+		// Attach files.
+		for _, f := range form.File["file"] {
+			file, err := f.Open()
+			if err != nil {
+				return echo.NewHTTPError(http.StatusInternalServerError,
+					app.i18n.Ts("globals.messages.invalidFields", "name", fmt.Sprintf("file: %s", err.Error())))
+			}
+			defer file.Close()
+
+			b, err := ioutil.ReadAll(file)
+			if err != nil {
+				return echo.NewHTTPError(http.StatusInternalServerError,
+					app.i18n.Ts("globals.messages.invalidFields", "name", fmt.Sprintf("file: %s", err.Error())))
+			}
+
+			m.Attachments = append(m.Attachments, models.TxAttachment{
+				Name:    f.Filename,
+				Header:  messenger.MakeAttachmentHeader(f.Filename, "base64"),
+				Content: b,
+			})
+		}
+	} else if err := c.Bind(&m); err != nil {
 		return err
 	}
 
@@ -85,6 +129,13 @@ func handleSendTxMessage(c echo.Context) error {
 		msg.ContentType = m.ContentType
 		msg.Messenger = m.Messenger
 		msg.Body = m.Body
+		for _, a := range m.Attachments {
+			msg.Attachments = append(msg.Attachments, messenger.Attachment{
+				Name:    a.Name,
+				Header:  a.Header,
+				Content: a.Content,
+			})
+		}
 
 		// Optional headers.
 		if len(m.Headers) != 0 {
diff --git a/internal/manager/manager.go b/internal/manager/manager.go
index aea79a6..fd044d7 100644
--- a/internal/manager/manager.go
+++ b/internal/manager/manager.go
@@ -411,16 +411,7 @@ func (m *Manager) worker() {
 				return
 			}
 
-			err := m.messengers[msg.Messenger].Push(messenger.Message{
-				From:        msg.From,
-				To:          msg.To,
-				Subject:     msg.Subject,
-				ContentType: msg.ContentType,
-				Body:        msg.Body,
-				AltBody:     msg.AltBody,
-				Subscriber:  msg.Subscriber,
-				Campaign:    msg.Campaign,
-			})
+			err := m.messengers[msg.Messenger].Push(msg.Message)
 			if err != nil {
 				m.logger.Printf("error sending message '%s': %v", msg.Subject, err)
 			}
diff --git a/models/models.go b/models/models.go
index 2d846a1..11bfc8a 100644
--- a/models/models.go
+++ b/models/models.go
@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"html/template"
+	"net/textproto"
 	"regexp"
 	"strings"
 	txttpl "text/template"
@@ -361,12 +362,22 @@ type TxMessage struct {
 	ContentType string                 `json:"content_type"`
 	Messenger   string                 `json:"messenger"`
 
+	// File attachments added from multi-part form data.
+	Attachments []TxAttachment `json:"-"`
+
 	Subject    string             `json:"-"`
 	Body       []byte             `json:"-"`
 	Tpl        *template.Template `json:"-"`
 	SubjectTpl *txttpl.Template   `json:"-"`
 }
 
+// TxAttachment is used by TxMessage, consists of FileName and file Content in bytes
+type TxAttachment struct {
+	Name    string
+	Header  textproto.MIMEHeader
+	Content []byte
+}
+
 // markdown is a global instance of Markdown parser and renderer.
 var markdown = goldmark.New(
 	goldmark.WithParserOptions(