Create Site in SharePoint Using custom solution and REST API

In today’s post, we will see how we can create a Communication Site through a custom form using the REST API.

The truth is I have developed several alternatives in the past, but let’s assume you have users who are not familiar with SharePoint and simply want to create a site without navigating through multiple options and forms.

We select a site that will host the form—the site generator.

Insert the Modern Script Editor web part.

Then insert the following code:

<div id="create-site-form" class="site-form-wrapper">
    <h2>Δημιουργία Νέου Communication Site</h2>
    
    <div class="field">
        <label>Όνομα Site:</label>
        <input type="text" id="site-title" placeholder="π.χ. My New Project">
    </div>

    <div class="field">
        <label>URL (Alias):</label>
        <div style="display:flex; align-items:center;">
            <span style="font-size:12px; color:#666; margin-right:5px;">/sites/</span>
            <input type="text" id="site-url" placeholder="my-new-project">
        </div>
    </div>

    <button id="btn-create-site" onclick="createCommSite()">Δημιουργία Site 🚀</button>
    
    <div id="status-message"></div>
</div>

<style>
    .site-form-wrapper {
        padding: 20px;
        background: #ffffff;
        border: 1px solid #ddd;
        border-radius: 8px;
        max-width: 400px;
        font-family: 'Segoe UI', sans-serif;
        box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    }
    .field { margin-bottom: 15px; }
    label { display: block; font-weight: 600; margin-bottom: 5px; color: #333; }
    input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; }
    button { 
        background: #0078d4; color: white; border: none; 
        padding: 12px 20px; cursor: pointer; border-radius: 4px; font-weight: bold; width: 100%;
    }
    button:disabled { background: #ccc; cursor: not-allowed; }
    #status-message { margin-top: 15px; font-size: 14px; line-height: 1.4; }
</style>

<script>
async function createCommSite() {
    const title = document.getElementById('site-title').value.trim();
    const urlAlias = document.getElementById('site-url').value.trim();
    const btn = document.getElementById('btn-create-site');
    const status = document.getElementById('status-message');

    if (!title || !urlAlias) {
        alert("Παρακαλώ συμπληρώστε όλα τα πεδία.");
        return;
    }

    btn.disabled = true;
    status.style.color = "#666";
    status.innerText = "Έναρξη διαδικασίας... παρακαλώ περιμένετε.";

    try {
        // 1. Αυτόματος προσδιορισμός URL του τρέχοντος site
        let siteUrl = window.location.origin;
        if (typeof _spPageContextInfo !== "undefined") {
            siteUrl = window.location.origin + _spPageContextInfo.webServerRelativeUrl;
        } else {
            const pathParts = window.location.pathname.split('/');
            if (pathParts.includes('sites') || pathParts.includes('teams')) {
                siteUrl = window.location.origin + pathParts.slice(0, 3).join('/');
            }
        }

        // 2. Λήψη Request Digest (Απαραίτητο για POST σε modern περιβάλλον)
        status.innerText = "Λήψη Security Token...";
        const contextRes = await fetch(`${siteUrl}/_api/contextinfo`, {
            method: "POST",
            headers: { "Accept": "application/json;odata=verbose" }
        });
        const contextData = await contextRes.json();
        const digest = contextData.d.GetContextWebInformation.FormDigestValue;

        // 3. Προετοιμασία Payload
        const fullSiteUrl = `${window.location.origin}/sites/${urlAlias}`;
        const endpoint = `${siteUrl}/_api/SPSiteManager/Create`;

        const payload = {
            "request": {
                "__metadata": { "type": "Microsoft.SharePoint.Portal.SPSiteCreationRequest" },
                "Title": title,
                "Url": fullSiteUrl,
                "Lcid": 1032, // 1032 για Ελληνικά
                "ShareByEmailEnabled": false,
                "WebTemplate": "SITEPAGEPUBLISHING#0", 
                "Description": "Created via custom REST script"
            }
        };

        status.innerText = "Δημιουργία στο Azure/SharePoint... (αυτό μπορεί να πάρει 10-20 δευτερόλεπτα)";

        // 4. Κλήση του API
        const response = await fetch(endpoint, {
            method: "POST",
            headers: {
                "Accept": "application/json;odata=verbose",
                "Content-Type": "application/json;odata=verbose",
                "X-RequestDigest": digest
            },
            body: JSON.stringify(payload)
        });

        const result = await response.json();

        // Το SiteStatus 2 σημαίνει 'Created'
        if (response.ok && result.d && result.d.Create && result.d.Create.SiteStatus === 2) {
            status.style.color = "green";
            status.innerHTML = `✅ <b>Επιτυχία!</b><br>Το site είναι έτοιμο: <a href="${result.d.Create.SiteUrl}" target="_blank" style="color:#0078d4; text-decoration:underline;">Επίσκεψη στο Site</a>`;
        } else {
            // Ανάλυση σφάλματος από το SharePoint
            const errorDetail = result.error ? result.error.message.value : "Το URL ίσως χρησιμοποιείται ή δεν έχετε δικαιώματα δημιουργίας.";
            throw new Error(errorDetail);
        }

    } catch (error) {
        console.error("Creation Error:", error);
        status.style.color = "red";
        status.innerText = "❌ Σφάλμα: " + error.message;
    } finally {
        btn.disabled = false;
    }
}
</script>