diff --git a/core/api/src/main/java/org/onosproject/net/pi/model/PiData.java b/core/api/src/main/java/org/onosproject/net/pi/model/PiData.java
new file mode 100644
index 0000000..97d5290
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/model/PiData.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.net.pi.model;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Representation of data that can be used for runtime operations of a protocol-independent pipeline.
+ */
+@Beta
+public interface PiData {
+    /**
+     * Types of data in a protocol-independent pipeline.
+     */
+    enum Type {
+        /**
+         * Bit String.
+         */
+        BITSTRING,
+
+        /**
+         * Bool.
+         */
+        BOOL,
+
+        /**
+         * Tuple.
+         */
+        TUPLE,
+
+        /**
+         * Struct.
+         */
+        STRUCT,
+
+        /**
+         * Header.
+         */
+        HEADER,
+
+        /**
+         * Header Stack.
+         */
+        HEADERSTACK,
+
+        /**
+         * Header Union.
+         */
+        HEADERUNION,
+
+        /**
+         * Header Union Stack.
+         */
+        HEADERUNIONSTACK,
+
+        /**
+         * Enum String.
+         */
+        ENUMSTRING,
+
+        /**
+         * Error String.
+         */
+        ERRORSTRING
+    }
+
+    /**
+     * Returns the type of this protocol-independent data.
+     * @return the type of this instance
+     */
+    Type type();
+}