diff --git a/cpp/src/storage/id_generators.cpp b/cpp/src/storage/id_generators.cpp
new file mode 100644
index 0000000000..8296a4048f
--- /dev/null
+++ b/cpp/src/storage/id_generators.cpp
@@ -0,0 +1,32 @@
+#include <chrono>
+#include <assert.h>
+
+#inlcude "id_generators.h"
+
+using std::chrono;
+
+namespace vecengine {
+
+IDGenerator::~IDGenerator() {}
+
+IDNumber SimpleIDGenerator::getNextIDNumber() {
+    auto now = chrono::system_clock::now();
+    auto micros = duration_cast<chrono::microseconds>(now.time_since_epoch()).count();
+    return micros * MAX_IDS_PER_MICRO
+}
+
+IDNumbers&& SimpleIDGenerator::getNextIDNumbers(size_t n) {
+    assert(n < MAX_IDS_PER_MICRO);
+    auto now = chrono::system_clock::now();
+    auto micros = duration_cast<chrono::microseconds>(now.time_since_epoch()).count();
+    micros *= MAX_IDS_PER_MICRO;
+
+    IDNumbers ids = IDNumbers(n);
+    for (int pos=0; pos<n; ++pos) {
+        ids[pos] = micros + pos;
+    }
+    return ids;
+}
+
+
+} // namespace vecengine
diff --git a/cpp/src/storage/id_generators.h b/cpp/src/storage/id_generators.h
new file mode 100644
index 0000000000..830b599a2a
--- /dev/null
+++ b/cpp/src/storage/id_generators.h
@@ -0,0 +1,35 @@
+#ifndef UTILS_ID_GENERATORS_H_
+#define UTILS_ID_GENERATORS_H_
+
+#include <vector>
+
+namespace vecengine {
+
+#define uint64_t IDNumber;
+#define IDNumber* IDNumberPtr;
+#define std::vector<IDNumber> IDNumbers;
+
+class IDGenerator {
+public:
+    virtual IDNumber getNextIDNumber() = 0;
+    virtual IDNumbers&& getNextIDNumbers(size_t n_) = 0;
+
+    virtual ~IDGenerator();
+
+}; // IDGenerator
+
+
+class SimpleIDGenerator : public IDGenerator {
+public:
+    virtual IDNumber getNextIDNumber() override;
+    virtual IDNumbers&& getNextIDNumbers(size_t n_) override;
+
+private:
+    const MAX_IDS_PER_MICRO = 1000;
+
+}; // SimpleIDGenerator
+
+
+} // namespace vecengine
+
+#endif // UTILS_ID_GENERATORS_H_
diff --git a/cpp/src/storage/memvectors.cpp b/cpp/src/storage/memvectors.cpp
new file mode 100644
index 0000000000..3a30dfda9e
--- /dev/null
+++ b/cpp/src/storage/memvectors.cpp
@@ -0,0 +1,84 @@
+#include <IndexFlat.h>
+#include <MetaIndexes.h>
+#include <index_io.h>
+
+#include "memvectors.h"
+
+
+namespace vecengine {
+
+MemVectors::MemVectors(size_t dimension_, const std::string& file_location_) :
+    _file_location(file_location_),
+    _pIdGenerator(new SimpleIDGenerator()),
+    _dimension(dimension_),
+    _pInnerIndex(new faiss::IndexFlat(_dimension)),
+    _pIdMapIndex = new faiss::IndexIDMap(_pInnerIndex) {
+}
+
+IDNumbers&& MemVectors::add(size_t n, const float* vectors) {
+    IDNumbers&& ids = _pIdGenerator->getNextIDNumbers(n);
+    _pIdMapIndex->add_with_ids(n, vectors, pIds, &ids[0]);
+    return ids;
+}
+
+size_t MemVectors::total() const {
+    return _pIdMapIndex->ntotal;
+}
+
+size_t MemVectors::approximate_size() const {
+    return total() * _dimension;
+}
+
+void MemVectors::serialize() {
+    faiss::write_index(_pIdMapIndex, _file_location);
+}
+
+MemVectors::~MemVectors() {
+    if (_pIdGenerator != nullptr) {
+        delete _pIdGenerator;
+        _pIdGenerator = nullptr;
+    }
+    if (_pIdMapIndex != nullptr) {
+        delete _pIdMapIndex;
+        _pIdMapIndex = nullptr;
+    }
+    if (_pInnerIndex != nullptr) {
+        delete _pInnerIndex;
+        _pInnerIndex = nullptr;
+    }
+}
+
+/*
+ * MemManager
+ */
+
+MemVectors* MemManager::get_mem_by_group(const std::string& group_id_) {
+    auto memIt = _memMap.find(group_id_);
+    if memIt != _memMap.end() {
+        return &(memIt->second);
+    }
+    // PXU TODO:
+    // 1. Read Group meta info
+    // 2. Initalize MemVectors base meta info
+    return nullptr;
+    /* GroupMetaInfo info; */
+    /* bool succ = env->getGroupMeta(group_id, &info); */
+    /* if (!succ) { */
+    /*     return nullptr; */
+    /* } */
+    /* _memMap[group_id] = MemVectors(info.dimension, info.next_file_location); */
+    /* return &(_memMap[group_id]); */
+}
+
+IDNumbers&& MemManager::add_vectors_no_lock(const std::string& group_id_,
+        size_t n,
+        const float* vectors) {
+    auto mem = get_group_mem(group_id_);
+    if (mem == nullptr) {
+        return IDNumbers();
+    }
+    return mem->add(n, vectors);
+}
+
+
+} // namespace vecengine
diff --git a/cpp/src/storage/memvectors.h b/cpp/src/storage/memvectors.h
new file mode 100644
index 0000000000..1a025f8d26
--- /dev/null
+++ b/cpp/src/storage/memvectors.h
@@ -0,0 +1,56 @@
+#ifndef STORAGE_VECENGINE_MEMVECTORS_H_
+#define STORAGE_VECENGINE_MEMVECTORS_H_
+
+#include <map>
+#include <string>
+#include "id_generators.h"
+
+class faiss::IndexIDMap;
+class faiss::Index;
+
+
+namespace vecengine {
+
+class MemVectors {
+public:
+    explicit MemVectors(size_t dimension_, const std::string& file_location_);
+
+    IDNumbers&& add(size_t n, const float* vectors);
+
+    size_t total() const;
+
+    size_t approximate_size() const;
+
+    void serialize();
+
+    ~MemVectors();
+
+private:
+    std::string _file_location;
+    IDGenerator* _pIdGenerator;
+    size_t _dimension;
+    faiss::Index* _pInnerIndex;
+    faiss::IndexIDMap* _pIdMapIndex;
+
+}; // MemVectors
+
+
+class MemManager {
+public:
+    MemManager() = default;
+
+    MemVectors* get_mem_by_group(const std::string& group_id_);
+
+private:
+    IDNumbers&& add_vectors_no_lock(const std::string& group_id_,
+            size_t n,
+            const float* vectors);
+
+    typedef std::map<std::string, MemVectors> MemMap;
+    MemMap _memMap;
+}; // MemManager
+
+
+} // namespace vecengine
+
+#endif
diff --git a/cpp/src/storage/serializers.h b/cpp/src/storage/serializers.h
new file mode 100644
index 0000000000..5356691530
--- /dev/null
+++ b/cpp/src/storage/serializers.h
@@ -0,0 +1,11 @@
+#ifndef STORAGE_SERIALIZERS_H_
+#define STORAGE_SERIALIZERS_H_
+
+class Serializer {
+public:
+
+
+}; // Serializer
+
+
+#endif // STORAGE_SERIALIZERS_H_