diff --git a/cpp/core/BUILD b/cpp/core/BUILD
index 9fa892fb..12456f0b 100644
--- a/cpp/core/BUILD
+++ b/cpp/core/BUILD
@@ -28,6 +28,7 @@ cc_library(
     ],
     deps = [
         ":core_types",
+        ":event_logger",
         "//absl/strings",
         "//absl/time",
         "//absl/types:span",
@@ -66,6 +67,16 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "event_logger",
+    hdrs = [
+        "event_logger.h",
+    ],
+    deps = [
+        "//logs/proto/location/nearby:nearby_client_log_cc_proto",
+    ],
+)
+
 cc_test(
     name = "core_test",
     size = "small",
diff --git a/cpp/core/event_logger.h b/cpp/core/event_logger.h
new file mode 100644
index 00000000..763eb1e3
--- /dev/null
+++ b/cpp/core/event_logger.h
@@ -0,0 +1,41 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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.
+
+#ifndef CORE_EVENT_LOGGER_H_
+#define CORE_EVENT_LOGGER_H_
+
+#include "logs/proto/location/nearby/nearby_client_log.proto.h"
+
+namespace location {
+namespace nearby {
+namespace connections {
+namespace analytics {
+
+// Allows callers to log |ConnectionsLog| collected at Nearby Connections
+// library. Callers need to implement the API if they want to collect this log.
+class EventLogger {
+ public:
+  virtual ~EventLogger() = default;
+
+  // Logs |ConnectionsLog| details. Might block to do I/O, e.g. upload
+  // synchronously to some metrics server.
+  virtual void Log(const logs::ConnectionsLog& connections_log) = 0;
+};
+
+}  // namespace analytics
+}  // namespace connections
+}  // namespace nearby
+}  // namespace location
+
+#endif  // CORE_EVENT_LOGGER_H_