diff --git a/README.md b/README.md
index 1faa8581..71795b6d 100644
--- a/README.md
+++ b/README.md
@@ -16,10 +16,20 @@ Some features:
 - name: Send mail
   uses: dawidd6/action-send-mail@v3
   with:
-    # Required mail server address:
+    # Specify connection via URL (replaces server_address, server_port, secure,
+    # username and password)
+    #
+    # Format:
+    #
+    #  * smtp://user:password@server:port
+    #  * smtp+starttls://user:password@server:port
+    connection_url: ${{secrets.MAIL_CONNECTION}}
+    # Required mail server address if not connection_url:
     server_address: smtp.gmail.com
-    # Required mail server port:
+    # Server port, default 25:
     server_port: 465
+    # Optional whether this connection use TLS (default is true if server_port is 465)
+    secure: true
     # Optional (recommended): mail server username:
     username: ${{secrets.MAIL_USERNAME}}
     # Optional (recommended) mail server password:
@@ -30,8 +40,6 @@ Some features:
     to: obiwan@example.com,yoda@example.com
     # Required sender full name (address can be skipped):
     from: Luke Skywalker # <user@example.com>
-    # Optional whether this connection use TLS (default is true if server_port is 465)
-    secure: true
     # Optional plain body:
     body: Build job of ${{github.repository}} completed successfully!
     # Optional HTML body read from file:
diff --git a/action.yml b/action.yml
index 33593b32..c1ed6faf 100644
--- a/action.yml
+++ b/action.yml
@@ -5,18 +5,19 @@ branding:
   icon: mail
   color: blue
 inputs:
+  connection_url:
+    description: Connection URL protocol://user:password@server:port, protocol can be smtp or smtp+starttls, replaces server_address, server_port, secure, username and password
   server_address:
     description: SMTP server address
-    required: true
   server_port:
     description: SMTP server port
-    required: true
+    default: "25"
+  secure:
+    description: Whether this connection use TLS (default is true if server_port is 465)
   username:
     description: Authenticate as this user to SMTP server
-    required: false
   password:
     description: Authenticate with this password to SMTP server
-    required: false
   subject:
     description: Subject of mail message
     required: true
@@ -26,9 +27,6 @@ inputs:
   from:
     description: Full name of mail sender (might be with an email address specified in <>)
     required: true
-  secure:
-    description: Whether this connection use TLS (default is true if server_port is 465)
-    required: false
   body:
     description: Body of mail message (might be a filename prefixed with file:// to read from)
     required: false
diff --git a/main.js b/main.js
index 3d2e1ace..d6485470 100644
--- a/main.js
+++ b/main.js
@@ -39,14 +39,48 @@ async function getAttachments(attachments) {
 
 async function main() {
     try {
-        const serverAddress = core.getInput("server_address", { required: true })
-        const serverPort = core.getInput("server_port", { required: true })
-        const username = core.getInput("username")
-        const password = core.getInput("password")
+        let serverAddress = core.getInput("server_address")
+        let serverPort = core.getInput("server_port")
+        let secure = core.getInput("secure")
+        let username = core.getInput("username")
+        let password = core.getInput("password")
+
+        if (!secure) {
+            secure = serverPort === "465"
+        }
+
+        const connectionUrl = core.getInput("connection_url")
+        if (connectionUrl) {
+            const url = new URL(connectionUrl)
+            switch (url.protocol) {
+                default:
+                    throw new Error(`Unsupported connection protocol '${url.protocol}'`);
+                case "smtp:":
+                    serverPort = "25";
+                    secure = "false"
+                    break;
+                case "smtp+starttls:":
+                    serverPort = "465";
+                    secure = "true"
+                    break;
+            }
+            if (url.hostname) {
+                serverAddress = url.hostname
+            }
+            if (url.port) {
+                serverPort = url.port
+            }
+            if (url.username) {
+                username = unescape(url.username)
+            }
+            if (url.password) {
+                password = unescape(url.password)
+            }
+        }
+
         const subject = core.getInput("subject", { required: true })
         const from = core.getInput("from", { required: true })
         const to = core.getInput("to", { required: true })
-        const secure = core.getInput("secure", { required: false })
         const body = core.getInput("body", { required: false })
         const htmlBody = core.getInput("html_body", { required: false })
         const cc = core.getInput("cc", { required: false })
@@ -58,6 +92,10 @@ async function main() {
         const ignoreCert = core.getInput("ignore_cert", { required: false })
         const priority = core.getInput("priority", { required: false })
 
+        if (!serverAddress) {
+            throw new Error("Server address must be specified");
+        }
+
         if (!username || !password) {
             core.warning("Username and password not specified. You should only do this if you are using a self-hosted runner to access an on-premise mail server.")
         }
@@ -69,7 +107,7 @@ async function main() {
                 pass: password
             } : undefined,
             port: serverPort,
-            secure: secure == "true" ? true : serverPort == "465",
+            secure: secure == "true",
             tls: ignoreCert == "true" ? {
                 rejectUnauthorized: false
             } : undefined,