diff --git a/youtokentome/cpp/bpe.cpp b/youtokentome/cpp/bpe.cpp
index 2a0fe73..fa748f5 100644
--- a/youtokentome/cpp/bpe.cpp
+++ b/youtokentome/cpp/bpe.cpp
@@ -865,7 +865,7 @@ void rename_tokens(ska::flat_hash_map<uint32_t, uint32_t> &char2id,
 }
 
 BPEState learn_bpe_from_string(string &text_utf8, int n_tokens,
-                               const string &output_file,
+                               StreamWriter &output,
                                BpeConfig bpe_config) {
   vector<std::thread> threads;
   assert(bpe_config.n_threads >= 1 || bpe_config.n_threads == -1);
@@ -1294,8 +1294,8 @@ BPEState learn_bpe_from_string(string &text_utf8, int n_tokens,
   rename_tokens(char2id, rules, bpe_config.special_tokens, n_tokens);
 
   BPEState bpe_state = {char2id, rules, bpe_config.special_tokens};
-  bpe_state.dump(output_file);
-  std::cerr << "model saved to: " << output_file << std::endl;
+  bpe_state.dump(output);
+  std::cerr << "model saved to: " << output.name() << std::endl;
   return bpe_state;
 }
 
@@ -1450,7 +1450,8 @@ void train_bpe(const string &input_path, const string &model_path,
   std::cerr << "reading file..." << std::endl;
   auto data = fast_read_file_utf8(input_path);
   std::cerr << "learning bpe..." << std::endl;
-  learn_bpe_from_string(data, vocab_size, model_path, bpe_config);
+  auto fout = StreamWriter.open(model_path);
+  learn_bpe_from_string(data, vocab_size, fout, bpe_config);
 }
 
 DecodeResult BaseEncoder::encode_sentence(const std::string &sentence_utf8,
diff --git a/youtokentome/cpp/bpe.h b/youtokentome/cpp/bpe.h
index dff9326..bd5ebc6 100644
--- a/youtokentome/cpp/bpe.h
+++ b/youtokentome/cpp/bpe.h
@@ -32,7 +32,7 @@ class BaseEncoder {
 
   explicit BaseEncoder(BPEState bpe_state, int _n_threads);
 
-  explicit BaseEncoder(const std::string& model_path, int n_threads);
+  explicit BaseEncoder(const StreamReader& model_path, int n_threads);
 
   void fill_from_state();
 
diff --git a/youtokentome/cpp/utils.cpp b/youtokentome/cpp/utils.cpp
index 901e6ef..a662c6c 100644
--- a/youtokentome/cpp/utils.cpp
+++ b/youtokentome/cpp/utils.cpp
@@ -2,20 +2,112 @@
 #include <cassert>
 #include <fstream>
 #include <iostream>
+#include <memory>
 #include <string>
 #include <vector>
 
+
 namespace vkcom {
 using std::string;
 using std::vector;
 
-void SpecialTokens::dump(std::ofstream &fout) {
-  fout << unk_id << " " << pad_id << " " << bos_id << " " << eos_id
-       << std::endl;
+class FileWriter : public StreamWriter {
+ public:
+  FileWriter(const std::string &file_name) {
+    this->file_name = file_name;
+    this->fout = std::ofstream(file_name, std::ios::out | std::ios::binary);
+    if (fout.fail()) {
+      std::cerr << "Can't open file: " << file_name << std::endl;
+      assert(false);
+    }
+  }
+
+  virtual int write(const char *buffer, int size) override {
+    return fout.write(buffer, size);
+  }
+
+  virtual std::string name() const noexcept override {
+    return file_name;
+  }
+
+ private:
+  std::string file_name;
+  std::ofstream fout;
+};
+
+class FileReader : public StreamReader {
+ public:
+  FileReader(const std::string &file_name) {
+    this->file_name = file_name;
+    this->fin = std::ifstream(file_name, std::ios::in | std::ios::binary);
+    if (fin.fail()) {
+      std::cerr << "Can't open file: " << file_name << std::endl;
+      assert(false);
+    }
+  }
+
+  virtual int read(const char *buffer, int size) override {
+    return fin.read(buffer, size);
+  }
+
+  virtual std::string name() const noexcept override {
+    return file_name;
+  }
+
+ private:
+  std::string file_name;
+  std::ifstream fin;
+};
+
+StreamWriter StreamWriter::open(const std::string &file_name) {
+  return FileWriter(file_name);
+}
+
+StreamReader StreamReader::open(const std::string &file_name) {
+  return FileReader(file_name);
+}
+
+template<typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
+T bin_to_int(const char *val) {
+  uint32_t ret = static_cast<unsigned char>(val[0]);
+  ret |= static_cast<uint32_t>(static_cast<unsigned char>(val[1])) << 8;
+  ret |= static_cast<uint32_t>(static_cast<unsigned char>(val[2])) << 16;
+  ret |= static_cast<uint32_t>(static_cast<unsigned char>(val[3])) << 24;
+  return ret;
+}
+
+template<typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
+std::unique_ptr<char[]> int_to_bin(T val) {
+  auto u32 = static_cast<uint32_t>(val);
+  std::unique_ptr<char[]> ret(new char[4]);
+  ret[0] = u32 & 0xFF;
+  ret[1] = (u32 >> 8) & 0xFF;
+  ret[2] = (u32 >> 16) & 0xFF;
+  ret[3] = (u32 >> 24);  // no need for & 0xFF
+  return std::move(ret);
+}
+
+void SpecialTokens::dump(StreamWriter &fout) {
+  std::unique_ptr<char[]> unk_id_ptr(int_to_bin(unk_id)),
+                          pad_id_ptr(int_to_bin(pad_id)),
+                          bos_id_ptr(int_to_bin(bos_id)),
+                          eos_id_ptr(int_to_bin(eos_id));
+  fout.write(unk_id_ptr.get(), 4);
+  fout.write(pad_id_ptr.get(), 4);
+  fout.write(bos_id_ptr.get(), 4);
+  fout.write(eos_id_ptr.get(), 4);
 }
 
-void SpecialTokens::load(std::ifstream &fin) {
-  fin >> unk_id >> pad_id >> bos_id >> eos_id;
+void SpecialTokens::load(StreamReader &fin) {
+  char unk_id_bs[4], pad_id_bs[4], bos_id_bs[4], eos_id_bs[4];
+  fin.read(unk_id_bs, 4);
+  fin.read(pad_id_bs, 4);
+  fin.read(bos_id_bs, 4);
+  fin.read(eos_id_bs, 4);
+  this->unk_id = bin_to_int<int>(unk_id_bs);
+  this->pad_id = bin_to_int<int>(pad_id_bs);
+  this->bos_id = bin_to_int<int>(bos_id_bs);
+  this->eos_id = bin_to_int<int>(eos_id_bs);
 }
 
 uint32_t SpecialTokens::max_id() const {
@@ -49,48 +141,69 @@ bool BPE_Rule::operator==(const BPE_Rule &other) const {
 
 BPE_Rule::BPE_Rule(uint32_t x, uint32_t y, uint32_t z) : x(x), y(y), z(z) {}
 
-void BPEState::dump(const string &file_name) {
-  std::ofstream fout(file_name, std::ios::out);
-  if (fout.fail()) {
-    std::cerr << "Can't open file: " << file_name << std::endl;
-    assert(false);
+void BPEState::dump(StreamWriter &fout) {
+  std::unique_ptr<char[]> char2id_ptr(int_to_bin(char2id.size())),
+                          rules_ptr(int_to_bin(rules.size()));
+  fout.write(char2id_ptr.get(), 4);
+  fout.write(rules_ptr.get(), 4);
+  for (auto &s : char2id) {
+    std::unique_ptr<char[]> first_ptr(int_to_bin(s.first)),
+                            second_ptr(int_to_bin(s.second));
+    fout.write(first_ptr.get(), 4);
+    fout.write(second_ptr.get(), 4);
   }
-  fout << char2id.size() << " " << rules.size() << std::endl;
-  for (auto s : char2id) {
-    fout << s.first << " " << s.second << std::endl;
+  for (auto &rule : rules) {
+    std::unique_ptr<char[]> rule_ptr(int_to_bin(rule.x));
+    fout.write(rule_ptr.get(), 4);
   }
-
-  for (auto rule : rules) {
-    fout << rule.x << " " << rule.y << " " << rule.z << std::endl;
+  for (auto &rule : rules) {
+    std::unique_ptr<char[]> rule_ptr(int_to_bin(rule.y));
+    fout.write(rule_ptr.get(), 4);
+  }
+  for (auto &rule : rules) {
+    std::unique_ptr<char[]> rule_ptr(int_to_bin(rule.z));
+    fout.write(rule_ptr.get(), 4);
   }
   special_tokens.dump(fout);
-  fout.close();
 }
 
-void BPEState::load(const string &file_name) {
+void BPEState::load(StreamReader &fin) {
   char2id.clear();
   rules.clear();
-  std::ifstream fin(file_name, std::ios::in);
-  if (fin.fail()) {
-    std::cerr << "Error. Can not open file with model: " << file_name
-              << std::endl;
-    exit(EXIT_FAILURE);
-  }
-  int n, m;
-  fin >> n >> m;
+  char n_bs[4], m_bs[4];
+  fin.read(n_bs, 4);
+  fin.read(m_bs, 4);
+  auto n = bin_to_int<int>(n_bs);
+  auto m = bin_to_int<int>(m_bs);
   for (int i = 0; i < n; i++) {
-    uint32_t inner_id;
-    uint32_t utf32_id;
-    fin >> inner_id >> utf32_id;
+    char inner_id_bs[4], utf32_id_bs[4];
+    fin.read(inner_id_bs, 4);
+    fin.read(utf32_id_bs, 4);
+    auto inner_id = bin_to_int<uint32_t>(inner_id_bs);
+    auto utf32_id = bin_to_int<uint32_t>(utf32_id_bs);
     char2id[inner_id] = utf32_id;
   }
+  std::vector<std::tuple<uint32_t, uint32_t, uint32_t>> rules_xyz(m);
+  for (int j = 0; j < 3; j++) {
+    for (int i = 0; i < m; i++) {
+      char val[4];
+      fin.read(val, 4);
+      uint32_t *element;
+      switch (j) {
+        case 0:
+          element = &std::get<0>(rules_xyz[i]);
+        case 1:
+          element = &std::get<1>(rules_xyz[i]);
+        case 2:
+          element = &std::get<2>(rules_xyz[i]);
+      }
+      *element = bin_to_int<uint32_t>(val);
+    }
+  }
   for (int i = 0; i < m; i++) {
-    uint32_t x, y, z;
-    fin >> x >> y >> z;
-    rules.emplace_back(x, y, z);
+    rules.emplace_back(std::get<0>(rules_xyz[i]), std::get<1>(rules_xyz[i]), std::get<2>(rules_xyz[i]));
   }
   special_tokens.load(fin);
-  fin.close();
 }
 
 BpeConfig::BpeConfig(double _character_coverage, int _n_threads,
diff --git a/youtokentome/cpp/utils.h b/youtokentome/cpp/utils.h
index d45346c..745fb7f 100644
--- a/youtokentome/cpp/utils.h
+++ b/youtokentome/cpp/utils.h
@@ -8,6 +8,22 @@
 namespace vkcom {
 const uint32_t SPACE_TOKEN = 9601;
 
+struct StreamWriter {
+  virtual int write(const char *buffer, int size) = 0;
+  virtual std::string name() const noexcept = 0;
+  virtual ~StreamWriter() = default;
+
+  static StreamWriter open(const std::string &file_name);
+};
+
+struct StreamReader {
+  virtual int read(const char *buffer, int size) = 0;
+  virtual std::string name() const noexcept = 0;
+  virtual ~StreamReader() = default;
+
+  static StreamReader open(const std::string &file_name);
+};
+
 struct BPE_Rule {
   // x + y -> z
   uint32_t x{0};
@@ -31,9 +47,9 @@ struct SpecialTokens {
 
   SpecialTokens(int pad_id, int unk_id, int bos_id, int eos_id);
 
-  void dump(std::ofstream &fout);
+  void dump(StreamWriter &fout);
 
-  void load(std::ifstream &fin);
+  void load(StreamReader &fin);
 
   uint32_t max_id() const;
 
@@ -58,9 +74,9 @@ struct BPEState {
   std::vector<BPE_Rule> rules;
   SpecialTokens special_tokens;
 
-  void dump(const std::string &file_name);
+  void dump(StreamWriter &fout);
 
-  void load(const std::string &file_name);
+  void load(StreamReader &fin);
 };
 
 struct DecodeResult {
diff --git a/youtokentome/youtokentome.py b/youtokentome/youtokentome.py
index e02c84a..a9df041 100644
--- a/youtokentome/youtokentome.py
+++ b/youtokentome/youtokentome.py
@@ -1,22 +1,32 @@
 from enum import Enum
-from typing import List, Union
+from functools import wraps
+from typing import BinaryIO, List, Optional, Union
 
 import _youtokentome_cython
 
+
 class OutputType(Enum):
     ID = 1
     SUBWORD = 2
 
+
 class BPE:
-    def __init__(self, model: str, n_threads: int = -1):
-        self.bpe_cython = _youtokentome_cython.BPE(
-            model_path=model, n_threads=n_threads
-        )
+    def __init__(self, model: Union[str, BinaryIO], n_threads: int = -1):
+        own_obj = isinstance(model, str)
+        if own_obj:
+            model = open(model, "rb")
+        try:
+            self.bpe_cython = _youtokentome_cython.BPE(
+                model_fobj=model, n_threads=n_threads
+            )
+        finally:
+            if own_obj:
+                model.close()
 
     @staticmethod
     def train(
         data: str,
-        model: str,
+        model: Optional[Union[str, BinaryIO]],
         vocab_size: int,
         coverage: float = 1.0,
         n_threads: int = -1,
@@ -25,17 +35,24 @@ def train(
         bos_id: int = 2,
         eos_id: int = 3,
     ) -> "BPE":
-        _youtokentome_cython.BPE.train(
-            data=data,
-            model=model,
-            vocab_size=vocab_size,
-            n_threads=n_threads,
-            coverage=coverage,
-            pad_id=pad_id,
-            unk_id=unk_id,
-            bos_id=bos_id,
-            eos_id=eos_id,
-        )
+        own_obj = isinstance(model, str)
+        if own_obj:
+            model = open(model, "wb")
+        try:
+            _youtokentome_cython.BPE.train(
+                data=data,
+                model=model,
+                vocab_size=vocab_size,
+                n_threads=n_threads,
+                coverage=coverage,
+                pad_id=pad_id,
+                unk_id=unk_id,
+                bos_id=bos_id,
+                eos_id=eos_id,
+            )
+        finally:
+            if own_obj:
+                model.close()
 
         return BPE(model=model, n_threads=n_threads)
 
@@ -61,6 +78,22 @@ def encode(
             reverse=reverse,
         )
 
+    def save(self, where: Union[str, BinaryIO]):
+        """
+        Write the model to FS or any writeable file object.
+
+        :param where: FS path or writeable file object.
+        :return: None
+        """
+        own_obj = isinstance(where, str)
+        if own_obj:
+            where = open(where, "wb")
+        try:
+            self.bpe_cython.save(where=where)
+        finally:
+            if own_obj:
+                where.close()
+
     def vocab_size(self) -> int:
         return self.bpe_cython.vocab_size()