Execution Contexts

SSJS exposes information about how the current page was invoked through the Platform.Request namespace. Understanding the execution context lets you write a single page that handles both GET and POST scenarios.

ExecutionContextType

Platform.Request.Method returns the HTTP verb: "GET" or "POST". Use it to distinguish form submissions from initial page loads:

<script runat="server">
Platform.Load("core", "1.1.5");

var method = Platform.Request.Method;

if (method === "POST") {
    // Handle form submission
    var email = Platform.Request.GetFormData("email");
    // ... process the form ...
    Write("<p>Thanks! We received: " + email + "</p>");
} else {
    // Render the form
    Write('<form method="post">');
    Write('<input name="email" type="email" placeholder="Your email">');
    Write('<button type="submit">Submit</button>');
    Write('</form>');
}
</script>

ExecutionContextName

Platform.Request.GetQueryStringParameter("_pageId") returns the CloudPages page ID. The system variable ExecutionContextName (when available) contains the name of the Automation or context that triggered execution.

In CloudPages, these built-in names are available:

Variable	Description
`Platform.Request.Method`	`"GET"` or `"POST"`
`Platform.Request.GetQueryStringParameter(name)`	Value from URL query string
`Platform.Request.GetFormData(name)`	Value from POST body (form-encoded)
`Platform.Request.GetPostData()`	Entire raw POST body (call only once)
`Platform.Request.GetCookieValue(name)`	Cookie value
`Platform.Request.GetRequestHeader(name)`	HTTP request header
`Platform.Request.HTTPRequestHeader(name)`	Same as above

Detecting the Environment

You can use feature detection to write code that degrades gracefully across contexts:

<script runat="server">
// Detect if we're in a web context (CloudPage vs email/automation)
var isWebContext = (Platform.Request.Method !== null &&
                   Platform.Request.Method !== "");

if (isWebContext) {
    var qs = Platform.Request.GetQueryStringParameter("debug");
    if (qs === "1") {
        // Show debug output
    }
}
</script>

GET Parameters

Read individual query string parameters with Platform.Request.GetQueryStringParameter():

<script runat="server">
var subscriberKey = Platform.Request.GetQueryStringParameter("sk");
var campaignId    = Platform.Request.GetQueryStringParameter("cid");

// Parameters not present in the URL return an empty string ""
if (!subscriberKey) {
    Platform.Response.Redirect("/error?code=no_sk");
}
</script>

Encrypted parameters: Use Platform.Function.CloudPagesURL() to generate URLs with encrypted parameters. Decrypt with Platform.Function.DecryptSymmetric() or rely on SFMC’s built-in decryption for CloudPagesURL-generated links.

POST Body

The POST body is available via two methods:

// Get a specific form field (application/x-www-form-urlencoded)
var email = Platform.Request.GetFormData("email");

// Get the entire raw POST body
var rawBody = Platform.Request.GetPostData();
// ⚠️ GetPostData() can only be called ONCE per request

JSON POST body pattern:

<script runat="server">
Platform.Load("core", "1.1.5");

if (Platform.Request.Method === "POST") {
    var rawBody = Platform.Request.GetPostData();
    // ParseJSON returns null if rawBody is null/undefined
    var payload = Platform.Function.ParseJSON(rawBody + "");

    if (payload && payload.email) {
        // Process...
    }
}
</script>

The + "" coercion prevents ParseJSON from throwing a 500 error on null/undefined input.

Cookies

// Read a cookie
var token = Platform.Request.GetCookieValue("session_token");

// Set a cookie
var expiry = Platform.Function.DateAdd(Platform.Function.Now(), 30, "D");
var expiryStr = Platform.Function.FormatDate(expiry, "M/D/YYYY H:MM:SS");
Platform.Response.SetCookie("session_token", tokenValue, expiryStr, true);
// Parameters: name, value, expiration-string, https-only

→ Next: Platform vs Core