diff --git a/knockout.postbox/knockout-postbox.d.ts b/knockout.postbox/knockout-postbox.d.ts
new file mode 100644
index 0000000000..341e817cb7
--- /dev/null
+++ b/knockout.postbox/knockout-postbox.d.ts
@@ -0,0 +1,49 @@
+interface KnockoutPostBox {
+    subscribe: (topic: string, handler: (value) => void, target?: any) => KnockoutObservableAny;
+    publish: (topic: string, value?: any) => KnockoutObservableAny;
+    defaultComparer: (newValue: any, oldValue: any) => bool;
+}
+
+interface KnockoutObservableString {
+    subscribeTo: (topic: string, useLastPublishedValueToInitialize?: bool, transform?: (val: any) => string) => KnockoutObservableString;
+    unsubscribeFrom: (topic: string) => KnockoutObservableString;
+    publishOn: (topic: string, skipInitialPublish?: bool, equalityComparer?: (newValue: string, oldValue: string) => bool) => KnockoutObservableString;
+    stopPublishingOn: (topic: string) => KnockoutObservableString;
+    syncWith: (topic: string, initializeWithLatestValue?: bool, skipInitialPublish?: bool, equalityComparer?: (newValue: string, oldValue: string) => bool) => KnockoutObservableString;
+}
+
+interface KnockoutObservableDate {
+    subscribeTo: (topic: string, useLastPublishedValueToInitialize?: bool, transform?: (val: any) => Date) => KnockoutObservableDate;
+    unsubscribeFrom: (topic: string) => KnockoutObservableDate;
+    publishOn: (topic: string, skipInitialPublish?: bool, equalityComparer?: (newValue: Date, oldValue: Date) => bool) => KnockoutObservableDate;
+    stopPublishingOn: (topic: string) => KnockoutObservableDate;
+    syncWith: (topic: string, initializeWithLatestValue?: bool, skipInitialPublish?: bool, equalityComparer?: (newValue: Date, oldValue: Date) => bool) => KnockoutObservableDate;
+}
+
+interface KnockoutObservableNumber {
+    subscribeTo: (topic: string, useLastPublishedValueToInitialize?: bool, transform?: (val: any) => number) => KnockoutObservableNumber;
+    unsubscribeFrom: (topic: string) => KnockoutObservableNumber;
+    publishOn: (topic: string, skipInitialPublish?: bool, equalityComparer?: (newValue: Number, oldValue: Number) => bool) => KnockoutObservableNumber;
+    stopPublishingOn: (topic: string) => KnockoutObservableNumber;
+    syncWith: (topic: string, initializeWithLatestValue?: bool, skipInitialPublish?: bool, equalityComparer?: (newValue: Number, oldValue: Number) => bool) => KnockoutObservableNumber;
+}
+
+interface KnockoutObservableBool {
+    subscribeTo: (topic: string, useLastPublishedValueToInitialize?: bool, transform?: (val: any) => bool) => KnockoutObservableBool;
+    unsubscribeFrom: (topic: string) => KnockoutObservableBool;
+    publishOn: (topic: string, skipInitialPublish?: bool, equalityComparer?: (newValue: bool, oldValue: bool) => bool) => KnockoutObservableBool;
+    stopPublishingOn: (topic: string) => KnockoutObservableBool;
+    syncWith: (topic: string, initializeWithLatestValue?: bool, skipInitialPublish?: bool, equalityComparer?: (newValue: bool, oldValue: bool) => bool) => KnockoutObservableBool;
+}
+
+interface KnockoutObservableAny {
+    subscribeTo: (topic: string, useLastPublishedValueToInitialize?: bool, transform?: (val: any) => any) => KnockoutObservableAny;
+    unsubscribeFrom: (topic: string) => KnockoutObservableAny;
+    publishOn: (topic: string, skipInitialPublish?: bool, equalityComparer?: (newValue: any, oldValue: any) => bool) => KnockoutObservableAny;
+    stopPublishingOn: (topic: string) => KnockoutObservableAny;
+    syncWith: (topic: string, initializeWithLatestValue?: bool, skipInitialPublish?: bool, equalityComparer?: (newValue: any, oldValue: any) => bool) => KnockoutObservableAny;
+}
+
+interface KnockoutStatic {
+    postbox: KnockoutPostBox;
+}
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