diff --git a/web/api/src/main/java/org/onosproject/codec/impl/CriterionCodec.java b/web/api/src/main/java/org/onosproject/codec/impl/CriterionCodec.java
new file mode 100644
index 0000000..81033f2
--- /dev/null
+++ b/web/api/src/main/java/org/onosproject/codec/impl/CriterionCodec.java
@@ -0,0 +1,119 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.codec.impl;
+
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.net.flow.criteria.Criteria;
+import org.onosproject.net.flow.criteria.Criterion;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Criterion codec.
+ */
+public class CriterionCodec extends JsonCodec<Criterion> {
+
+    protected static final Logger log = LoggerFactory.getLogger(CriterionCodec.class);
+
+    @Override
+    public ObjectNode encode(Criterion criterion, CodecContext context) {
+        checkNotNull(criterion, "Criterion cannot be null");
+
+        final ObjectNode result = context.mapper().createObjectNode()
+                .put("type", criterion.type().toString());
+
+        switch (criterion.type()) {
+
+            case IN_PORT:
+                final Criteria.PortCriterion portCriterion = (Criteria.PortCriterion) criterion;
+                result.put("tcpPort", portCriterion.port().toLong());
+                break;
+
+            case ETH_SRC:
+            case ETH_DST:
+                final Criteria.EthCriterion ethCriterion = (Criteria.EthCriterion) criterion;
+                break;
+
+            case ETH_TYPE:
+                final Criteria.EthTypeCriterion ethTypeCriterion =
+                        (Criteria.EthTypeCriterion) criterion;
+                result.put("ethType", ethTypeCriterion.ethType());
+                break;
+
+            case IPV4_SRC:
+            case IPV6_SRC:
+                final Criteria.IPCriterion iPCriterion = (Criteria.IPCriterion) criterion;
+                result.put("ip", iPCriterion.ip().toString());
+                break;
+
+            case IP_PROTO:
+                final Criteria.IPProtocolCriterion iPProtocolCriterion =
+                        (Criteria.IPProtocolCriterion) criterion;
+                result.put("protocol", iPProtocolCriterion.protocol());
+                break;
+
+            case VLAN_PCP:
+                final Criteria.VlanPcpCriterion vlanPcpCriterion =
+                        (Criteria.VlanPcpCriterion) criterion;
+                result.put("priority", vlanPcpCriterion.priority());
+                break;
+
+            case VLAN_VID:
+                final Criteria.VlanIdCriterion vlanIdCriterion =
+                        (Criteria.VlanIdCriterion) criterion;
+                result.put("vlanId", vlanIdCriterion.vlanId().toShort());
+                break;
+
+            case TCP_SRC:
+            case TCP_DST:
+                final Criteria.TcpPortCriterion tcpPortCriterion =
+                        (Criteria.TcpPortCriterion) criterion;
+                result.put("tcpPort", tcpPortCriterion.tcpPort().byteValue());
+                break;
+
+            case MPLS_LABEL:
+                final Criteria.MplsCriterion mplsCriterion =
+                        (Criteria.MplsCriterion) criterion;
+                result.put("label", mplsCriterion.label());
+                break;
+
+            case OCH_SIGID:
+                final Criteria.LambdaCriterion lambdaCriterion =
+                        (Criteria.LambdaCriterion) criterion;
+                result.put("lambda", lambdaCriterion.lambda());
+                break;
+
+            case OCH_SIGTYPE:
+                final Criteria.OpticalSignalTypeCriterion opticalSignalTypeCriterion =
+                        (Criteria.OpticalSignalTypeCriterion) criterion;
+                result.put("signalType", opticalSignalTypeCriterion.signalType());
+                break;
+
+            default:
+                // Don't know how to format this type
+                log.info("Cannot convert criterion of type {} to JSON",
+                        criterion.type());
+                break;
+        }
+
+        return result;
+    }
+}