Getting Started

Your first steps with Server-Side JavaScript in Salesforce Marketing Cloud.

Server-Side JavaScript (SSJS) is a JavaScript-based scripting language that runs on the SFMC server before a page or email is sent to a subscriber or browser. Unlike client-side JavaScript that runs in the browser, SSJS has no DOM, no window, no document — but it has direct access to SFMC platform APIs.

In This Section

• What is SSJS? — Origins, capabilities, and how it differs from client-side JavaScript
• Where SSJS Runs — CloudPages, Email, Automation Studio, JSON Code Resources, and more
• Embedding SSJS — <script runat="server"> syntax, language attribute, multiple blocks
• Execution Contexts — GET vs POST, ExecutionContextType, ExecutionContextName
• Platform vs Core — The two library layers and when to use each

Five-Minute Setup

<script runat="server">
// 1. Load the Core library (required for DataExtension, Subscriber, etc.)
Platform.Load("core", "1.1.5");

// 2. Wrap in try/catch to prevent blank pages on errors
try {
    // 3. Read a query string parameter
    var name = Platform.Request.GetQueryStringParameter("name");

    // 4. Sanitize / default
    if (!name) { name = "World"; }

    // 5. Write output to the page
    Write("<h1>Hello, " + name + "!</h1>");

} catch (e) {
    Write("<p class='error'>Error: " + Stringify(e) + "</p>");
}
</script>

What Makes SSJS Different

Feature	SSJS	Client JS (browser)
Runs on	SFMC server	Subscriber’s browser
DOM access	No	Yes
SFMC APIs	Direct	Via REST only
ES version	~ES3/5 (JINT engine)	Modern
let / const	No — use var	Yes
Arrow functions	No	Yes
async/await	No	Yes
JSON.parse	No — use Platform.Function.ParseJSON()	Yes

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