diff --git a/benchmark/hashset_memory.cpp b/benchmark/hashset_memory.cpp
index 67e871d67..ab453faaa 100644
--- a/benchmark/hashset_memory.cpp
+++ b/benchmark/hashset_memory.cpp
@@ -33,7 +33,7 @@ static bool use_memprof() {
 #endif
 }
 
-static auto get_memory() {
+static td::uint64 get_memory() {
 #if USE_MEMPROF
   if (use_memprof()) {
     return get_used_memory_size();
diff --git a/tdutils/td/utils/FlatHashMap.h b/tdutils/td/utils/FlatHashMap.h
index 618097b59..bb6d6f391 100644
--- a/tdutils/td/utils/FlatHashMap.h
+++ b/tdutils/td/utils/FlatHashMap.h
@@ -73,81 +73,142 @@ class fixed_vector {
   size_t size_{0};
 };
 
-template <class KeyT, class ValueT, class HashT = std::hash<KeyT>>
-class FlatHashMapImpl {
- public:
-  struct Node {
-    using first_type = KeyT;
-    using second_type = ValueT;
-    KeyT first{};
-    union {
-      ValueT second;
-    };
-    const auto &key() const {
-      return first;
-    }
-    auto &value() {
-      return second;
-    }
+// TODO: move
+template <class KeyT>
+bool is_key_empty(const KeyT &key) {
+  return key == KeyT();
+}
 
-    Node() {
-    }
-    Node(KeyT key, ValueT value) : first(std::move(key)) {
-      new (&second) ValueT(std::move(value));
-      DCHECK(!empty());
-    }
-    ~Node() {
-      if (!empty()) {
-        second.~ValueT();
-      }
-    }
-    Node(Node &&other) noexcept {
-      *this = std::move(other);
-    }
-    Node &operator=(Node &&other) noexcept {
-      DCHECK(empty());
-      DCHECK(!other.empty());
-      first = std::move(other.first);
-      other.first = KeyT{};
-      new (&second) ValueT(std::move(other.second));
-      other.second.~ValueT();
-      return *this;
-    }
-
-    bool empty() const {
-      return is_key_empty(key());
-    }
-
-    void clear() {
-      DCHECK(!empty());
-      first = KeyT();
-      second.~ValueT();
-      DCHECK(empty());
-    }
-
-    template <class... ArgsT>
-    void emplace(KeyT key, ArgsT &&...args) {
-      DCHECK(empty());
-      first = std::move(key);
-      new (&second) ValueT(std::forward<ArgsT>(args)...);
-      DCHECK(!empty());
-    }
+template <class KeyT, class ValueT>
+struct MapNode {
+  using first_type = KeyT;
+  using second_type = ValueT;
+  using key_type = KeyT;
+  using public_type = MapNode<KeyT, ValueT>;
+  using value_type = ValueT;
+  KeyT first{};
+  union {
+    ValueT second;
   };
-  using Self = FlatHashMapImpl<KeyT, ValueT, HashT>;
+  const auto &key() const {
+    return first;
+  }
+  auto &value() {
+    return second;
+  }
+  auto &get_public() {
+    return *this;
+  }
+
+  MapNode() {
+  }
+  MapNode(KeyT key, ValueT value) : first(std::move(key)) {
+    new (&second) ValueT(std::move(value));
+        DCHECK(!empty());
+  }
+  ~MapNode() {
+    if (!empty()) {
+      second.~ValueT();
+    }
+  }
+  MapNode(MapNode &&other) noexcept {
+    *this = std::move(other);
+  }
+  MapNode &operator=(MapNode &&other) noexcept {
+        DCHECK(empty());
+        DCHECK(!other.empty());
+    first = std::move(other.first);
+    other.first = KeyT{};
+    new (&second) ValueT(std::move(other.second));
+    other.second.~ValueT();
+    return *this;
+  }
+
+  bool empty() const {
+    return is_key_empty(key());
+  }
+
+  void clear() {
+        DCHECK(!empty());
+    first = KeyT();
+    second.~ValueT();
+        DCHECK(empty());
+  }
+
+  template <class... ArgsT>
+  void emplace(KeyT key, ArgsT &&...args) {
+        DCHECK(empty());
+    first = std::move(key);
+    new (&second) ValueT(std::forward<ArgsT>(args)...);
+        DCHECK(!empty());
+  }
+};
+
+template <class KeyT>
+struct SetNode {
+  using first_type = KeyT;
+  using key_type = KeyT;
+  using public_type = KeyT;
+  using value_type = KeyT;
+  KeyT first{};
+  const auto &key() const {
+    return first;
+  }
+  const auto &value() const {
+    return first;
+  }
+
+  auto &get_public() {
+    return first;
+  }
+  SetNode() = default;
+  explicit SetNode(KeyT key) : first(std::move(key)) {
+  }
+  SetNode(SetNode &&other) noexcept {
+    *this = std::move(other);
+  }
+  SetNode &operator=(SetNode &&other) noexcept {
+        DCHECK(empty());
+        DCHECK(!other.empty());
+    first = std::move(other.first);
+    other.first = KeyT{};
+    return *this;
+  }
+
+  bool empty() const {
+    return is_key_empty(key());
+  }
+
+  void clear() {
+    first = KeyT();
+    CHECK(empty());
+  }
+
+  void emplace(KeyT key) {
+    first = std::move(key);
+  }
+};
+
+template <class NodeT, class HashT, class EqT>
+class FlatHashTable {
+ public:
+  using Self = FlatHashTable<NodeT, HashT, EqT>;
+  using Node = NodeT;
   using NodeIterator = typename fixed_vector<Node>::iterator;
   using ConstNodeIterator = typename fixed_vector<Node>::const_iterator;
 
-  using key_type = KeyT;
-  using value_type = Node;
+  using KeyT = typename Node::key_type;
+  using public_type = typename Node::public_type;
+  using value_type = typename Node::value_type;
 
   struct Iterator {
     using iterator_category = std::bidirectional_iterator_tag;
     using difference_type = std::ptrdiff_t;
-    using value_type = Node;
-    using pointer = Node *;
-    using reference = Node &;
+    using value_type = public_type;
+    using pointer = public_type *;
+    using reference = public_type &;
 
-    friend class FlatHashMapImpl;
+    friend class FlatHashTable;
     Iterator &operator++() {
       do {
         ++it_;
@@ -160,21 +221,22 @@ class FlatHashMapImpl {
       } while (it_->empty());
       return *this;
     }
-    Node &operator*() {
-      return *it_;
+    reference operator*() {
+      return it_->get_public();
     }
-    Node *operator->() {
+    pointer operator->() {
       return &*it_;
     }
     bool operator==(const Iterator &other) const {
-      DCHECK(map_ == other.map_);
+          DCHECK(map_ == other.map_);
       return it_ == other.it_;
     }
     bool operator!=(const Iterator &other) const {
-      DCHECK(map_ == other.map_);
+          DCHECK(map_ == other.map_);
       return it_ != other.it_;
     }
 
+    Iterator() = default;
     Iterator(NodeIterator it, Self *map) : it_(std::move(it)), map_(map) {
     }
 
@@ -186,11 +248,11 @@ class FlatHashMapImpl {
   struct ConstIterator {
     using iterator_category = std::bidirectional_iterator_tag;
     using difference_type = std::ptrdiff_t;
-    using value_type = Node;
-    using pointer = const Node *;
-    using reference = const Node &;
+    using value_type = public_type;
+    using pointer = const value_type *;
+    using reference = const value_type &;
 
-    friend class FlatHashMapImpl;
+    friend class FlatHashTable;
     ConstIterator &operator++() {
       ++it_;
       return *this;
@@ -199,10 +261,10 @@ class FlatHashMapImpl {
       --it_;
       return *this;
     }
-    const Node &operator*() {
+    reference operator*() {
       return *it_;
     }
-    const Node *operator->() {
+    pointer operator->() {
       return &*it_;
     }
     bool operator==(const ConstIterator &other) const {
@@ -212,25 +274,28 @@ class FlatHashMapImpl {
       return it_ != other.it_;
     }
 
-    explicit ConstIterator(Iterator it) : it_(std::move(it)) {
+    ConstIterator() = default;
+    ConstIterator(Iterator it) : it_(std::move(it)) {
     }
 
    private:
     Iterator it_;
   };
+  using iterator = Iterator;
+  using const_iterator = ConstIterator;
 
-  FlatHashMapImpl() = default;
-  FlatHashMapImpl(const FlatHashMapImpl &other) : FlatHashMapImpl(other.begin(), other.end()) {
+  FlatHashTable() = default;
+  FlatHashTable(const FlatHashTable &other) : FlatHashTable(other.begin(), other.end()) {
   }
-  FlatHashMapImpl &operator=(const FlatHashMapImpl &other) {
+  FlatHashTable &operator=(const FlatHashTable &other) {
     assign(other.begin(), other.end());
     return *this;
   }
 
-  FlatHashMapImpl(std::initializer_list<Node> nodes) {
+  FlatHashTable(std::initializer_list<Node> nodes) {
     reserve(nodes.size());
     for (auto &node : nodes) {
-      CHECK(!is_key_empty(node.first));
+      CHECK(!node.empty());
       auto bucket = calc_bucket(node.first);
       while (true) {
         if (nodes_[bucket].key() == node.first) {
@@ -247,29 +312,38 @@ class FlatHashMapImpl {
     }
   }
 
-  FlatHashMapImpl(FlatHashMapImpl &&other) noexcept : nodes_(std::move(other.nodes_)), used_nodes_(other.used_nodes_) {
+  FlatHashTable(FlatHashTable &&other) noexcept : nodes_(std::move(other.nodes_)), used_nodes_(other.used_nodes_) {
     other.used_nodes_ = 0;
   }
-  FlatHashMapImpl &operator=(FlatHashMapImpl &&other) noexcept {
+  FlatHashTable &operator=(FlatHashTable &&other) noexcept {
     nodes_ = std::move(other.nodes_);
     used_nodes_ = other.used_nodes_;
     other.used_nodes_ = 0;
     return *this;
   }
-  ~FlatHashMapImpl() = default;
+  void swap(FlatHashTable &other) noexcept {
+    using std::swap;
+    swap(nodes_, other.nodes_);
+    swap(used_nodes_, other.used_nodes_);
+  }
+  ~FlatHashTable() = default;
 
   template <class ItT>
-  FlatHashMapImpl(ItT begin, ItT end) {
+  FlatHashTable(ItT begin, ItT end) {
     assign(begin, end);
   }
 
+  size_t bucket_count() const {
+    return nodes_.size();
+  }
+
   Iterator find(const KeyT &key) {
     if (empty() || is_key_empty(key)) {
       return end();
     }
     auto bucket = calc_bucket(key);
     while (true) {
-      if (nodes_[bucket].key() == key) {
+      if (EqT()(nodes_[bucket].key(), key)) {
         return Iterator{nodes_.begin() + bucket, this};
       }
       if (nodes_[bucket].empty()) {
@@ -326,7 +400,7 @@ class FlatHashMapImpl {
     CHECK(!is_key_empty(key));
     auto bucket = calc_bucket(key);
     while (true) {
-      if (nodes_[bucket].key() == key) {
+      if (EqT()(nodes_[bucket].key(), key)) {
         return {Iterator{nodes_.begin() + bucket, this}, false};
       }
       if (nodes_[bucket].empty()) {
@@ -338,8 +412,19 @@ class FlatHashMapImpl {
     }
   }
 
-  ValueT &operator[](const KeyT &key) {
-    return emplace(key).first->second;
+  std::pair<Iterator, bool> insert(KeyT key) {
+    return emplace(std::move(key));
+  }
+
+  template <class ItT>
+  void insert(ItT begin, ItT end)  {
+    for (; begin != end; ++begin) {
+      emplace(*begin);
+    }
+  }
+
+  value_type &operator[](const KeyT &key) {
+    return emplace(key).first->value();
   }
 
   size_t erase(const KeyT &key) {
@@ -363,7 +448,7 @@ class FlatHashMapImpl {
 
   void erase(Iterator it) {
     DCHECK(it != end());
-    DCHECK(!is_key_empty(it->key()));
+    DCHECK(!it.it_->empty());
     erase_node(it.it_);
   }
 
@@ -392,9 +477,6 @@ class FlatHashMapImpl {
   }
 
  private:
-  static bool is_key_empty(const KeyT &key) {
-    return key == KeyT();
-  }
 
   fixed_vector<Node> nodes_;
   size_t used_nodes_{};
@@ -496,8 +578,18 @@ class FlatHashMapImpl {
   }
 };
 
-template <class KeyT, class ValueT, class HashT = std::hash<KeyT>>
-using FlatHashMap = FlatHashMapImpl<KeyT, ValueT, HashT>;
-//using FlatHashMap = std::unordered_map<KeyT, ValueT, HashT>;
+template <class KeyT, class ValueT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
+using FlatHashMapImpl = FlatHashTable<MapNode<KeyT, ValueT>, HashT, EqT>;
+template <class KeyT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
+using FlatHashSetImpl = FlatHashTable<SetNode<KeyT>, HashT, EqT>;
+
+template <class KeyT, class ValueT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
+using FlatHashMap = FlatHashMapImpl<KeyT, ValueT, HashT, EqT>;
+//using FlatHashMap = std::unordered_map<KeyT, ValueT, HashT, EqT>;
+
+template <class KeyT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
+using FlatHashSet = FlatHashSetImpl<KeyT, HashT, EqT>;
+//using FlatHashSet = std::unordered_set<KeyT, HashT, EqT>;
+
 
 }  // namespace td
diff --git a/tdutils/td/utils/algorithm.h b/tdutils/td/utils/algorithm.h
index 1ebfd6f56..0c3702d8c 100644
--- a/tdutils/td/utils/algorithm.h
+++ b/tdutils/td/utils/algorithm.h
@@ -206,11 +206,11 @@ void table_remove_if(TableT &table, FuncT &&func) {
   }
 }
 
-template <class KeyT, class ValueT, class HashT>
-class FlatHashMapImpl;
+template <class NodeT, class HashT, class EqT>
+class FlatHashTable;
 
-template <class KeyT, class ValueT, class HashT, class FuncT>
-void table_remove_if(FlatHashMapImpl<KeyT, ValueT, HashT> &table, FuncT &&func) {
+template <class NodeT, class HashT, class EqT, class FuncT>
+void table_remove_if(FlatHashTable<NodeT, HashT, EqT> &table, FuncT &&func) {
   table.remove_if(func);
 }
 
diff --git a/tdutils/test/HashSet.cpp b/tdutils/test/HashSet.cpp
index d0a1ad2e1..773944ac5 100644
--- a/tdutils/test/HashSet.cpp
+++ b/tdutils/test/HashSet.cpp
@@ -24,6 +24,17 @@ static auto extract_kv(const T &reference) {
 }
 
 TEST(FlatHashMap, basic) {
+  {
+      td::FlatHashSet<int> s;
+      s.insert(5);
+      for (auto x : s) {
+      }
+      int N = 100000;
+      for (int i = 0; i < 10000000; i++) {
+        s.insert((i + N/2)%N);
+        s.erase(i%N);
+      }
+  }
   {
     td::FlatHashMap<int, int> map;
     map[1] = 2;
diff --git a/tdutils/test/hashset_benchmark.cpp b/tdutils/test/hashset_benchmark.cpp
index 07e4b1d80..714726eb4 100644
--- a/tdutils/test/hashset_benchmark.cpp
+++ b/tdutils/test/hashset_benchmark.cpp
@@ -248,7 +248,7 @@ static void BM_emplace_same(benchmark::State &state) {
 
   while (state.KeepRunningBatch(BATCH_SIZE)) {
     for (size_t i = 0; i < BATCH_SIZE; i++) {
-      benchmark::DoNotOptimize(table.emplace(key, 43784932));
+      benchmark::DoNotOptimize(table.emplace(key + (i & 15) * 100 , 43784932));
     }
   }
 }
@@ -375,6 +375,28 @@ static void BM_remove_if_slow(benchmark::State &state) {
   constexpr size_t N = 5000;
   constexpr size_t BATCH_SIZE = 500000;
 
+  TableT table;
+  td::Random::Xorshift128plus rnd(123);
+  for (size_t i = 0; i < N; i++) {
+    table.emplace(rnd() + 1, i);
+  }
+  auto first_key = table.begin()->first;
+  {
+    size_t cnt = 0;
+    td::table_remove_if(table, [&cnt](auto &) { cnt += 2; return cnt <= N; });
+  }
+  while (state.KeepRunningBatch(BATCH_SIZE)) {
+    for (size_t i = 0; i < BATCH_SIZE; i++) {
+      table.emplace(first_key, i);
+      table.erase(first_key);
+    }
+  }
+}
+template <typename TableT>
+static void BM_remove_if_slow_old(benchmark::State &state) {
+  constexpr size_t N = 100000;
+  constexpr size_t BATCH_SIZE = 500000;
+
   TableT table;
   while (state.KeepRunningBatch(BATCH_SIZE)) {
     td::Random::Xorshift128plus rnd(123);
@@ -452,14 +474,13 @@ static void benchmark_create(td::Slice name) {
 #define REGISTER_ERASE_ALL_BENCHMARK(HT) BENCHMARK_TEMPLATE(BM_erase_all_with_begin, HT<td::uint64, td::uint64>);
 #define REGISTER_REMOVE_IF_SLOW_BENCHMARK(HT) BENCHMARK_TEMPLATE(BM_remove_if_slow, HT<td::uint64, td::uint64>);
 
-FOR_EACH_TABLE(REGISTER_CACHE3_BENCHMARK)
-FOR_EACH_TABLE(REGISTER_CACHE_BENCHMARK)
-FOR_EACH_TABLE(REGISTER_CACHE2_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_REMOVE_IF_SLOW_BENCHMARK)
-FOR_EACH_TABLE(REGISTER_ERASE_ALL_BENCHMARK)
+FOR_EACH_TABLE(REGISTER_CACHE3_BENCHMARK)
+FOR_EACH_TABLE(REGISTER_CACHE2_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_CACHE_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_REMOVE_IF_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_EMPLACE_BENCHMARK)
+FOR_EACH_TABLE(REGISTER_ERASE_ALL_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_GET_BENCHMARK)
 FOR_EACH_TABLE(REGISTER_FIND_BENCHMARK)