diff --git a/include/sled/futures/detail/base_future.h b/include/sled/futures/detail/base_future.h
new file mode 100644
index 0000000..bbaff54
--- /dev/null
+++ b/include/sled/futures/detail/base_future.h
@@ -0,0 +1,66 @@
+#ifndef SLED_FUTURES_DETAIL_BASE_FUTURE_H
+#define SLED_FUTURES_DETAIL_BASE_FUTURE_H
+#include "sled/any.h"
+#include "sled/synchronization/mutex.h"
+#include <memory>
+#include <type_traits>
+
+namespace sled {
+
+template<typename T>
+class Promise;
+
+template<typename T>
+class FutureState {
+public:
+    T Get()
+    {
+        sled::MutexLock lock(&mutex_);
+        cv_.Wait(&mutex_, [this]() { return done_; });
+        return sled::any_cast<T>(value_);
+    }
+
+    void SetError(std::exception_ptr e)
+    {
+        sled::MutexLock lock(&mutex_);
+        value_ = e;
+        done_ = true;
+    };
+
+    template<typename U = T>
+    typename std::enable_if<!std::is_void<T>::value && std::is_convertible<U, T>::value>::type SetValue(U &&value)
+    {
+        sled::MutexLock lock(&mutex_);
+        value_ = static_cast<T>(std::forward<U>(value));
+        done_ = true;
+    }
+
+    template<typename U = T>
+    typename std::enable_if<std::is_void<T>::value>::type SetValue(U &&value)
+    {
+        sled::MutexLock lock(&mutex_);
+        done_ = true;
+    }
+
+private:
+    sled::Mutex mutex_;
+    sled::ConditionVariable cv_;
+    sled::any value_;
+    bool done_{false};
+};
+
+template<typename T>
+class BaseFuture {
+public:
+    template<typename T>
+    T Get() const
+    {
+        return state_->Get();
+    }
+
+private:
+    std::shared_ptr<FutureState<T>> state_;
+};
+
+}// namespace sled
+#endif// SLED_FUTURES_DETAIL_BASE_FUTURE_H
diff --git a/src/futures/promise_test.cc b/src/futures/promise_test.cc
index db6f6dc..fffe6f1 100644
--- a/src/futures/promise_test.cc
+++ b/src/futures/promise_test.cc
@@ -1,5 +1,4 @@
 #include <gtest/gtest.h>
-#include <sled/futures/promise.h>
 
 TEST(Promise, Basic)
 {