diff --git a/EnvelopeGenerator.API/Models/BlazorSignaturePayload.cs b/EnvelopeGenerator.API/Models/BlazorSignaturePayload.cs
new file mode 100644
index 00000000..3bc0b0c2
--- /dev/null
+++ b/EnvelopeGenerator.API/Models/BlazorSignaturePayload.cs
@@ -0,0 +1,42 @@
+namespace EnvelopeGenerator.API.Models;
+
+/// <summary>
+/// Lightweight payload used by the Blazor receiver UI to submit signatures.
+/// Each entry corresponds to one signature placeholder rendered as an
+/// overlay on top of the DevExpress PDF viewer.
+///
+/// The legacy MVC flow ships a full PSPDFKit InstantJSON payload via
+/// <see cref="EnvelopeGenerator.Application.Common.Notifications.DocSigned.PsPdfKitAnnotation"/>.
+/// That format is browser-library specific. The Blazor client uses a
+/// transport-neutral DTO instead: only what the server actually needs
+/// to persist the signed document (image + metadata per placeholder).
+///
+/// Conversion to the internal <c>PsPdfKitAnnotation</c> happens inside
+/// <see cref="EnvelopeGenerator.API.Controllers.AnnotationController"/>.
+/// </summary>
+public class BlazorSignaturePayload
+{
+    /// <summary>The receiver-specific signed placeholders for this envelope.</summary>
+    public List<BlazorSignatureEntry> Signatures { get; set; } = new();
+}
+
+/// <summary>
+/// A single signed placeholder.
+/// </summary>
+public class BlazorSignatureEntry
+{
+    /// <summary>The receiver's <c>DocumentReceiverElement.Id</c> being signed.</summary>
+    public int ElementId { get; set; }
+
+    /// <summary>Signature image as a data URL (e.g. "data:image/png;base64,...").</summary>
+    public string SignatureDataUrl { get; set; } = string.Empty;
+
+    /// <summary>Optional position / job title entered by the receiver.</summary>
+    public string? Position { get; set; }
+
+    /// <summary>Optional city / location entered by the receiver.</summary>
+    public string? City { get; set; }
+
+    /// <summary>Capture timestamp (client local time).</summary>
+    public DateTime SignedAt { get; set; }
+}