--- a/dom/interfaces/payments/nsIPaymentRequest.idl
+++ b/dom/interfaces/payments/nsIPaymentRequest.idl
@@ -25,16 +25,17 @@ interface nsIPaymentCurrencyAmount : nsI
 };
 
 [scriptable, builtinclass, uuid(4f78a59f-b5ff-4fb5-ab48-3b37d0101b02)]
 interface nsIPaymentItem : nsISupports
 {
   readonly attribute AString label;
   readonly attribute nsIPaymentCurrencyAmount amount;
   readonly attribute boolean pending;
+  readonly attribute AString type;
 };
 
 [scriptable, builtinclass, uuid(74259861-c318-40e8-b3d5-518e701bed80)]
 interface nsIPaymentDetailsModifier : nsISupports
 {
   readonly attribute AString supportedMethods;
   readonly attribute nsIPaymentItem total;
   readonly attribute nsIArray additionalDisplayItems;

--- a/dom/payments/PaymentRequestData.cpp
+++ b/dom/payments/PaymentRequestData.cpp
@@ -103,35 +103,37 @@ PaymentCurrencyAmount::GetValue(nsAStrin
 
 /* PaymentItem */
 
 NS_IMPL_ISUPPORTS(PaymentItem,
                   nsIPaymentItem)
 
 PaymentItem::PaymentItem(const nsAString& aLabel,
                          nsIPaymentCurrencyAmount* aAmount,
-                         const bool aPending)
+                         const bool aPending,
+                         const nsAString& aType)
   : mLabel(aLabel)
   , mAmount(aAmount)
   , mPending(aPending)
+  , mType(aType)
 {
 }
 
 nsresult
 PaymentItem::Create(const IPCPaymentItem& aIPCItem, nsIPaymentItem** aItem)
 {
   NS_ENSURE_ARG_POINTER(aItem);
   nsCOMPtr<nsIPaymentCurrencyAmount> amount;
   nsresult rv = PaymentCurrencyAmount::Create(aIPCItem.amount(),
                                               getter_AddRefs(amount));
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
   nsCOMPtr<nsIPaymentItem> item =
-    new PaymentItem(aIPCItem.label(), amount, aIPCItem.pending());
+    new PaymentItem(aIPCItem.label(), amount, aIPCItem.pending(), aIPCItem.type());
   item.forget(aItem);
   return NS_OK;
 }
 
 NS_IMETHODIMP
 PaymentItem::GetLabel(nsAString& aLabel)
 {
   aLabel = mLabel;
@@ -151,16 +153,23 @@ PaymentItem::GetAmount(nsIPaymentCurrenc
 NS_IMETHODIMP
 PaymentItem::GetPending(bool* aPending)
 {
   NS_ENSURE_ARG_POINTER(aPending);
   *aPending = mPending;
   return NS_OK;
 }
 
+NS_IMETHODIMP
+PaymentItem::GetType(nsAString& aType)
+{
+  aType = mType;
+  return NS_OK;
+}
+
 /* PaymentDetailsModifier */
 
 NS_IMPL_ISUPPORTS(PaymentDetailsModifier,
                   nsIPaymentDetailsModifier)
 
 PaymentDetailsModifier::PaymentDetailsModifier(const nsAString& aSupportedMethods,
                                                nsIPaymentItem* aTotal,
                                                nsIArray* aAdditionalDisplayItems,

--- a/dom/payments/PaymentRequestData.h
+++ b/dom/payments/PaymentRequestData.h
@@ -60,23 +60,25 @@ public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSIPAYMENTITEM
 
   static nsresult Create(const IPCPaymentItem& aIPCItem, nsIPaymentItem** aItem);
 
 private:
   PaymentItem(const nsAString& aLabel,
               nsIPaymentCurrencyAmount* aAmount,
-              const bool aPending);
+              const bool aPending,
+              const nsAString& aType);
 
   ~PaymentItem() = default;
 
   nsString mLabel;
   nsCOMPtr<nsIPaymentCurrencyAmount> mAmount;
   bool mPending;
+  nsString mType;
 };
 
 class PaymentDetailsModifier final : public nsIPaymentDetailsModifier
 {
 public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSIPAYMENTDETAILSMODIFIER
 

--- a/dom/payments/PaymentRequestManager.cpp
+++ b/dom/payments/PaymentRequestManager.cpp
@@ -46,19 +46,28 @@ ConvertCurrencyAmount(const PaymentCurre
                       IPCPaymentCurrencyAmount& aIPCCurrencyAmount)
 {
   aIPCCurrencyAmount = IPCPaymentCurrencyAmount(aAmount.mCurrency, aAmount.mValue);
 }
 
 void
 ConvertItem(const PaymentItem& aItem, IPCPaymentItem& aIPCItem)
 {
+  uint8_t typeIndex = UINT8_MAX;
+  if (aItem.mType.WasPassed()) {
+    typeIndex = static_cast<uint8_t>(aItem.mType.Value());
+  }
+  nsString type;
+  if (typeIndex < ArrayLength(PaymentItemTypeValues::strings)) {
+    type.AssignASCII(
+      PaymentItemTypeValues::strings[typeIndex].value);
+  }
   IPCPaymentCurrencyAmount amount;
   ConvertCurrencyAmount(aItem.mAmount, amount);
-  aIPCItem = IPCPaymentItem(aItem.mLabel, amount, aItem.mPending);
+  aIPCItem = IPCPaymentItem(aItem.mLabel, amount, aItem.mPending, type);
 }
 
 nsresult
 ConvertModifier(JSContext* aCx,
                 const PaymentDetailsModifier& aModifier,
                 IPCPaymentDetailsModifier& aIPCModifier)
 {
   NS_ENSURE_ARG_POINTER(aCx);

--- a/dom/payments/ipc/PPaymentRequest.ipdl
+++ b/dom/payments/ipc/PPaymentRequest.ipdl
@@ -22,16 +22,17 @@ struct IPCPaymentCurrencyAmount
   nsString value;
 };
 
 struct IPCPaymentItem
 {
   nsString label;
   IPCPaymentCurrencyAmount amount;
   bool pending;
+  nsString type;
 };
 
 struct IPCPaymentDetailsModifier
 {
   nsString supportedMethods;
   IPCPaymentItem total;
   IPCPaymentItem[] additionalDisplayItems;
   nsString data;

--- a/dom/payments/test/ConstructorChromeScript.js
+++ b/dom/payments/test/ConstructorChromeScript.js
@@ -136,39 +136,58 @@ function checkComplexRequest(payRequest)
   if (details.totalItem.amount.value != "100.00") {
     emitTestFail("total item's value should be '100.00'.");
   }
 
   const displayItems = details.displayItems;
   if (!details.displayItems) {
     emitTestFail("details.displayItems should not be undefined.");
   }
-  if (displayItems.length != 2) {
-    emitTestFail("displayItems' length should be 2.")
+  if (displayItems.length != 3) {
+    emitTestFail("displayItems' length should be 3.")
   }
   let item = displayItems.queryElementAt(0, Ci.nsIPaymentItem);
   if (item.label != "First item") {
     emitTestFail("1st display item's label should be 'First item'.");
   }
   if (item.amount.currency != "USD") {
     emitTestFail("1st display item's currency should be 'USD'.");
   }
   if (item.amount.value != "60.00") {
     emitTestFail("1st display item's value should be '60.00'.");
   }
+  if (item.type != "") {
+    emitTestFail("1st display item's type should be ''.");
+  }
   item = displayItems.queryElementAt(1, Ci.nsIPaymentItem);
   if (item.label != "Second item") {
     emitTestFail("2nd display item's label should be 'Second item'.");
   }
   if (item.amount.currency != "USD") {
     emitTestFail("2nd display item's currency should be 'USD'.");
   }
   if (item.amount.value != "40.00") {
     emitTestFail("2nd display item's value should be '40.00'.");
   }
+  if (item.type != "") {
+    emitTestFail("2nd display item's type should be ''.");
+  }
+  item = displayItems.queryElementAt(2, Ci.nsIPaymentItem);
+  if (item.label != "Tax") {
+    emitTestFail("3rd display item's label should be 'Tax'.");
+  }
+  if (item.amount.currency != "USD") {
+    emitTestFail("3rd display item's currency should be 'USD'.");
+  }
+  if (item.amount.value != "5.00") {
+    emitTestFail("3rd display item's value should be '5.00'.");
+  }
+  if (item.type != "tax") {
+    emitTestFail("3rd display item's type should be 'tax'.");
+  }
 
   const modifiers = details.modifiers;
   if (!modifiers) {
     emitTestFail("details.displayItems should not be undefined.");
   }
   if (modifiers.length != 1) {
     emitTestFail("modifiers' length should be 1.");
   }

--- a/dom/payments/test/test_constructor.html
+++ b/dom/payments/test/test_constructor.html
@@ -70,16 +70,24 @@ https://bugzilla.mozilla.org/show_bug.cg
         }
       },
       {
         label: "Second item",
         amount: {
           currency: "USD",
           value: "40.00"
         }
+      },
+      {
+        label: "Tax",
+        amount: {
+          currency: "USD",
+          value: "5.00"
+        },
+        type: "tax"
       }
     ],
     modifiers: [
       {
         supportedMethods: "basic-card",
         total: {
           label: "Discounted Total",
           amount: {

--- a/dom/webidl/PaymentRequest.webidl
+++ b/dom/webidl/PaymentRequest.webidl
@@ -13,20 +13,25 @@ dictionary PaymentMethodData {
 };
 
 dictionary PaymentCurrencyAmount {
   required DOMString currency;
   required DOMString value;
            DOMString currencySystem = "urn:iso:std:iso:4217";
 };
 
+enum PaymentItemType {
+  "tax"
+};
+
 dictionary PaymentItem {
   required DOMString             label;
   required PaymentCurrencyAmount amount;
            boolean               pending = false;
+           PaymentItemType       type;
 };
 
 dictionary PaymentShippingOption {
   required DOMString             id;
   required DOMString             label;
   required PaymentCurrencyAmount amount;
            boolean               selected = false;
 };