diff --git a/aos/BUILD b/aos/BUILD
index b6d357b..83adcd6 100644
--- a/aos/BUILD
+++ b/aos/BUILD
@@ -850,3 +850,12 @@
         "//aos/events:simulated_event_loop_rs",
     ],
 )
+
+cc_library(
+    name = "shared_span",
+    hdrs = ["shared_span.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "@com_google_absl//absl/types:span",
+    ],
+)
diff --git a/aos/events/BUILD b/aos/events/BUILD
index ace634c..c61b3e5 100644
--- a/aos/events/BUILD
+++ b/aos/events/BUILD
@@ -116,6 +116,7 @@
         "//aos:flatbuffers",
         "//aos:ftrace",
         "//aos:realtime",
+        "//aos:shared_span",
         "//aos:uuid",
         "//aos/flatbuffers:builder",
         "//aos/ipc_lib:data_alignment",
diff --git a/aos/events/event_loop.h b/aos/events/event_loop.h
index d45dddf..389ea08 100644
--- a/aos/events/event_loop.h
+++ b/aos/events/event_loop.h
@@ -24,6 +24,7 @@
 #include "aos/ftrace.h"
 #include "aos/ipc_lib/data_alignment.h"
 #include "aos/json_to_flatbuffer.h"
+#include "aos/shared_span.h"
 #include "aos/time/time.h"
 #include "aos/util/phased_loop.h"
 #include "aos/util/status.h"
@@ -90,8 +91,6 @@
   Ftrace ftrace_;
 };
 
-using SharedSpan = std::shared_ptr<const absl::Span<const uint8_t>>;
-
 // Holds storage for a span object and the data referenced by that span for
 // compatibility with SharedSpan users. If constructed with MakeSharedSpan, span
 // points to only the aligned segment of the entire data.
@@ -113,8 +112,6 @@
 // and as a building block to implement typed senders.
 class RawSender {
  public:
-  using SharedSpan = std::shared_ptr<const absl::Span<const uint8_t>>;
-
   enum class [[nodiscard]] Error {
     // Represents success and no error
     kOk,
diff --git a/aos/flatbuffers/BUILD b/aos/flatbuffers/BUILD
index 0f25875..e4f7d1d 100644
--- a/aos/flatbuffers/BUILD
+++ b/aos/flatbuffers/BUILD
@@ -28,6 +28,7 @@
     target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
+        "//aos:shared_span",
         "//aos/containers:resizeable_buffer",
         "//aos/ipc_lib:data_alignment",
         "@com_github_google_flatbuffers//:flatbuffers",
diff --git a/aos/flatbuffers/base.h b/aos/flatbuffers/base.h
index b3c3ef0..a98d730 100644
--- a/aos/flatbuffers/base.h
+++ b/aos/flatbuffers/base.h
@@ -18,11 +18,9 @@
 
 #include "aos/containers/resizeable_buffer.h"
 #include "aos/ipc_lib/data_alignment.h"
+#include "aos/shared_span.h"
 
-namespace aos {
-using SharedSpan = std::shared_ptr<const absl::Span<const uint8_t>>;
-
-namespace fbs {
+namespace aos::fbs {
 
 using ::flatbuffers::soffset_t;
 using ::flatbuffers::uoffset_t;
@@ -343,7 +341,6 @@
   T t;
 };
 }  // namespace internal
-}  // namespace fbs
-}  // namespace aos
+}  // namespace aos::fbs
 
 #endif  // AOS_FLATBUFFERS_BASE_H_
diff --git a/aos/shared_span.h b/aos/shared_span.h
new file mode 100644
index 0000000..515c0bf
--- /dev/null
+++ b/aos/shared_span.h
@@ -0,0 +1,16 @@
+#ifndef AOS_SHARED_SPAN_H_
+#define AOS_SHARED_SPAN_H_
+
+#include <cstdint>
+#include <memory>
+
+#include "absl/types/span.h"
+
+namespace aos {
+
+// Shared pointer to a region of memory.  The pointer needs to own the region.
+using SharedSpan = std::shared_ptr<const absl::Span<const uint8_t>>;
+
+}  // namespace aos
+
+#endif  // AOS_SHARED_SPAN_H_