diff --git a/tensorflow/core/platform/BUILD b/tensorflow/core/platform/BUILD
index 874f1f2092c..59cc6d68732 100644
--- a/tensorflow/core/platform/BUILD
+++ b/tensorflow/core/platform/BUILD
@@ -86,6 +86,7 @@ exports_files(
         "mutex.h",
         "net.h",
         "numa.h",
+        "ram_file_system.h",
         "resource_loader.h",
         "resource.h",
         "snappy.h",
@@ -382,6 +383,15 @@ cc_library(
     ],
 )
 
+py_test(
+    name = "ram_file_system_test",
+    srcs = ["ram_file_system_test.py"],
+    python_version = "PY3",
+    deps = [
+        "//tensorflow:tensorflow_py",
+    ],
+)
+
 cc_library(
     name = "numbers",
     srcs = ["numbers.cc"],
@@ -1293,6 +1303,7 @@ filegroup(
         "profile_utils/cpu_utils.h",
         "profile_utils/i_cpu_utils_helper.h",
         "protobuf.h",
+        "ram_file_system.h",
         "random.h",
         "resource.h",
         "stacktrace.h",
@@ -1507,6 +1518,7 @@ filegroup(
         "protobuf.cc",
         "protobuf.h",
         "protobuf_util.cc",
+        "ram_file_system.h",
         "raw_coding.h",
         "refcount.h",
         "resource.h",
diff --git a/tensorflow/core/platform/default/BUILD b/tensorflow/core/platform/default/BUILD
index db714938a45..49318fd0811 100644
--- a/tensorflow/core/platform/default/BUILD
+++ b/tensorflow/core/platform/default/BUILD
@@ -87,6 +87,7 @@ cc_library(
         "//tensorflow/core/platform:env.h",
         "//tensorflow/core/platform:file_system.h",
         "//tensorflow/core/platform:file_system_helper.h",
+        "//tensorflow/core/platform:ram_file_system.h",
         "//tensorflow/core/platform:threadpool.h",
     ],
     tags = [
diff --git a/tensorflow/core/platform/default/env.cc b/tensorflow/core/platform/default/env.cc
index 5f7822f6583..e33155a4414 100644
--- a/tensorflow/core/platform/default/env.cc
+++ b/tensorflow/core/platform/default/env.cc
@@ -38,6 +38,7 @@ limitations under the License.
 #include "tensorflow/core/platform/load_library.h"
 #include "tensorflow/core/platform/logging.h"
 #include "tensorflow/core/platform/mutex.h"
+#include "tensorflow/core/platform/ram_file_system.h"
 #include "tensorflow/core/protobuf/error_codes.pb.h"
 
 namespace tensorflow {
@@ -214,6 +215,8 @@ class PosixEnv : public Env {
 #if defined(PLATFORM_POSIX) || defined(__APPLE__) || defined(__ANDROID__)
 REGISTER_FILE_SYSTEM("", PosixFileSystem);
 REGISTER_FILE_SYSTEM("file", LocalPosixFileSystem);
+REGISTER_FILE_SYSTEM("ram", RamFileSystem);
+
 Env* Env::Default() {
   static Env* default_env = new PosixEnv;
   return default_env;
diff --git a/tensorflow/core/platform/ram_file_system.h b/tensorflow/core/platform/ram_file_system.h
new file mode 100644
index 00000000000..abd673b455c
--- /dev/null
+++ b/tensorflow/core/platform/ram_file_system.h
@@ -0,0 +1,232 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_CORE_PLATFORM_RAM_FILE_SYSTEM_H_
+#define TENSORFLOW_CORE_PLATFORM_RAM_FILE_SYSTEM_H_
+
+// Implementation of an in-memory TF filesystem for simple prototyping (e.g.
+// via Colab). The TPU TF server does not have local filesystem access, which
+// makes it difficult to provide Colab tutorials: users must have GCS access
+// and sign-in in order to try out an example.
+//
+// Files are implemented on top of std::string. Directories, as with GCS or S3,
+// are implicit based on the existence of child files. Multiple files may
+// reference a single FS location, though no thread-safety guarantees are
+// provided.
+
+#include <string>
+
+#include "tensorflow/core/platform/env.h"
+#include "tensorflow/core/platform/file_system.h"
+#include "tensorflow/core/platform/mutex.h"
+#include "tensorflow/core/platform/stringpiece.h"
+#include "tensorflow/core/platform/types.h"
+
+#ifdef PLATFORM_WINDOWS
+#undef DeleteFile
+#undef CopyFile
+#undef TranslateName
+#endif
+
+namespace tensorflow {
+
+class RamRandomAccessFile : public RandomAccessFile, public WritableFile {
+ public:
+  RamRandomAccessFile(std::string name, std::shared_ptr<std::string> cord)
+      : name_(name), data_(cord) {}
+  ~RamRandomAccessFile() override {}
+
+  Status Name(StringPiece* result) const override {
+    *result = name_;
+    return Status::OK();
+  }
+
+  Status Read(uint64 offset, size_t n, StringPiece* result,
+              char* scratch) const override {
+    if (offset >= data_->size()) {
+      return errors::OutOfRange("");
+    }
+
+    uint64 left = std::min(static_cast<uint64>(n), data_->size() - offset);
+    auto start = data_->begin() + offset;
+    auto end = data_->begin() + offset + left;
+
+    std::copy(start, end, scratch);
+    *result = StringPiece(scratch, left);
+
+    // In case of a partial read, we must still fill `result`, but also return
+    // OutOfRange.
+    if (left < n) {
+      return errors::OutOfRange("");
+    }
+    return Status::OK();
+  }
+
+  Status Append(StringPiece data) override {
+    data_->append(data.data(), data.size());
+    return Status::OK();
+  }
+
+  Status Close() override { return Status::OK(); }
+  Status Flush() override { return Status::OK(); }
+  Status Sync() override { return Status::OK(); }
+
+  Status Tell(int64* position) override {
+    *position = -1;
+    return errors::Unimplemented("This filesystem does not support Tell()");
+  }
+
+ private:
+  TF_DISALLOW_COPY_AND_ASSIGN(RamRandomAccessFile);
+  string name_;
+  std::shared_ptr<std::string> data_;
+};
+
+class RamFileSystem : public FileSystem {
+ public:
+  Status NewRandomAccessFile(
+      const string& fname, std::unique_ptr<RandomAccessFile>* result) override {
+    mutex_lock m(mu_);
+    if (fs_.find(fname) == fs_.end()) {
+      return errors::NotFound("");
+    }
+    *result = std::unique_ptr<RandomAccessFile>(
+        new RamRandomAccessFile(fname, fs_[fname]));
+    return Status::OK();
+  }
+
+  Status NewWritableFile(const string& fname,
+                         std::unique_ptr<WritableFile>* result) override {
+    mutex_lock m(mu_);
+    if (fs_.find(fname) == fs_.end()) {
+      fs_[fname] = std::make_shared<std::string>();
+    }
+    *result = std::unique_ptr<WritableFile>(
+        new RamRandomAccessFile(fname, fs_[fname]));
+    return Status::OK();
+  }
+  Status NewAppendableFile(const string& fname,
+                           std::unique_ptr<WritableFile>* result) override {
+    mutex_lock m(mu_);
+    if (fs_.find(fname) == fs_.end()) {
+      fs_[fname] = std::make_shared<std::string>();
+    }
+    *result = std::unique_ptr<WritableFile>(
+        new RamRandomAccessFile(fname, fs_[fname]));
+    return Status::OK();
+  }
+
+  Status NewReadOnlyMemoryRegionFromFile(
+      const string& fname,
+      std::unique_ptr<ReadOnlyMemoryRegion>* result) override {
+    return errors::Unimplemented("");
+  }
+
+  Status FileExists(const string& fname) override {
+    FileStatistics stat;
+    return Stat(fname, &stat);
+  }
+
+  Status GetChildren(const string& dir, std::vector<string>* result) override {
+    mutex_lock m(mu_);
+    auto it = fs_.lower_bound(dir);
+    while (it != fs_.end() && absl::StartsWith(it->first, dir)) {
+      result->push_back(it->first);
+      ++it;
+    }
+
+    return Status::OK();
+  }
+
+  Status GetMatchingPaths(const string& pattern,
+                          std::vector<string>* results) override {
+    mutex_lock m(mu_);
+    Env* env = Env::Default();
+    for (auto it = fs_.begin(); it != fs_.end(); ++it) {
+      if (env->MatchPath(it->first, pattern)) {
+        results->push_back(it->first);
+      }
+    }
+    return Status::OK();
+  }
+
+  Status Stat(const string& fname, FileStatistics* stat) override {
+    mutex_lock m(mu_);
+    auto it = fs_.lower_bound(fname);
+    if (it == fs_.end()) {
+      return errors::NotFound("");
+    }
+
+    if (it->first == fname) {
+      stat->is_directory = false;
+      stat->length = fs_[fname]->size();
+      stat->mtime_nsec = 0;
+      return Status::OK();
+    }
+
+    stat->is_directory = true;
+    stat->length = 0;
+    stat->mtime_nsec = 0;
+    return Status::OK();
+  }
+
+  Status DeleteFile(const string& fname) override {
+    mutex_lock m(mu_);
+    if (fs_.find(fname) != fs_.end()) {
+      fs_.erase(fname);
+      return Status::OK();
+    }
+
+    return errors::NotFound("");
+  }
+
+  Status CreateDir(const string& dirname) override { return Status::OK(); }
+
+  Status RecursivelyCreateDir(const string& dirname) override {
+    return Status::OK();
+  }
+
+  Status DeleteDir(const string& dirname) override { return Status::OK(); }
+
+  Status GetFileSize(const string& fname, uint64* file_size) override {
+    mutex_lock m(mu_);
+    if (fs_.find(fname) != fs_.end()) {
+      *file_size = fs_[fname]->size();
+      return Status::OK();
+    }
+    return errors::NotFound("");
+  }
+
+  Status RenameFile(const string& src, const string& target) override {
+    mutex_lock m(mu_);
+    if (fs_.find(src) != fs_.end()) {
+      fs_[target] = fs_[src];
+      fs_.erase(fs_.find(src));
+      return Status::OK();
+    }
+    return errors::NotFound("");
+  }
+
+  RamFileSystem() {}
+  ~RamFileSystem() override {}
+
+ private:
+  mutex mu_;
+  std::map<string, std::shared_ptr<std::string>> fs_;
+};
+
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_CORE_PLATFORM_RAM_FILE_SYSTEM_H_
diff --git a/tensorflow/core/platform/ram_file_system_test.py b/tensorflow/core/platform/ram_file_system_test.py
new file mode 100644
index 00000000000..0f4f47ec44e
--- /dev/null
+++ b/tensorflow/core/platform/ram_file_system_test.py
@@ -0,0 +1,119 @@
+# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+"""Tests for ram_file_system.h."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import numpy as np
+
+from tensorflow.python.estimator.estimator import Estimator
+from tensorflow.python.estimator.model_fn import EstimatorSpec
+from tensorflow.python.estimator.run_config import RunConfig
+from tensorflow.python.framework import constant_op
+from tensorflow.python.framework import dtypes
+from tensorflow.python.framework import test_util
+from tensorflow.python.layers import core as core_layers
+from tensorflow.python.ops.losses import losses
+from tensorflow.python.platform import gfile
+from tensorflow.python.platform import test
+from tensorflow.python.training import adam
+from tensorflow.python.training import training_util
+
+
+class RamFilesystemTest(test_util.TensorFlowTestCase):
+
+  def test_write_file(self):
+    with gfile.GFile('ram://a.txt', 'w') as f:
+      f.write('Hello, world.')
+      f.write('Hello, world.')
+
+    with gfile.GFile('ram://a.txt', 'r') as f:
+      self.assertEqual(f.read(), 'Hello, world.' * 2)
+
+  def test_append_file_with_seek(self):
+    with gfile.GFile('ram://c.txt', 'w') as f:
+      f.write('Hello, world.')
+
+    with gfile.GFile('ram://c.txt', 'w+') as f:
+      f.seek(offset=0, whence=2)
+      f.write('Hello, world.')
+
+    with gfile.GFile('ram://c.txt', 'r') as f:
+      self.assertEqual(f.read(), 'Hello, world.' * 2)
+
+  def test_list_dir(self):
+    for i in range(10):
+      with gfile.GFile('ram://a/b/%d.txt' % i, 'w') as f:
+        f.write('')
+      with gfile.GFile('ram://c/b/%d.txt' % i, 'w') as f:
+        f.write('')
+
+    matches = ['ram://a/b/%d.txt' % i for i in range(10)]
+    self.assertEqual(gfile.ListDirectory('ram://a/b/'), matches)
+
+  def test_glob(self):
+    for i in range(10):
+      with gfile.GFile('ram://a/b/%d.txt' % i, 'w') as f:
+        f.write('')
+      with gfile.GFile('ram://c/b/%d.txt' % i, 'w') as f:
+        f.write('')
+
+    matches = ['ram://a/b/%d.txt' % i for i in range(10)]
+    self.assertEqual(gfile.Glob('ram://a/b/*'), matches)
+
+    matches = []
+    self.assertEqual(gfile.Glob('ram://b/b/*'), matches)
+
+    matches = ['ram://c/b/%d.txt' % i for i in range(10)]
+    self.assertEqual(gfile.Glob('ram://c/b/*'), matches)
+
+  def test_estimator(self):
+
+    def model_fn(features, labels, mode, params):
+      del params
+      x = core_layers.dense(features, 100)
+      x = core_layers.dense(x, 100)
+      x = core_layers.dense(x, 100)
+      x = core_layers.dense(x, 100)
+      y = core_layers.dense(x, 1)
+      loss = losses.mean_squared_error(labels, y)
+      opt = adam.AdamOptimizer(learning_rate=0.1)
+      train_op = opt.minimize(
+          loss, global_step=training_util.get_or_create_global_step())
+
+      return EstimatorSpec(mode=mode, loss=loss, train_op=train_op)
+
+    def input_fn():
+      batch_size = 128
+      return (constant_op.constant(np.random.randn(batch_size, 100),
+                                   dtype=dtypes.float32),
+              constant_op.constant(np.random.randn(batch_size, 1),
+                                   dtype=dtypes.float32))
+
+    config = RunConfig(
+        model_dir='ram://estimator-0/', save_checkpoints_steps=1)
+    estimator = Estimator(config=config, model_fn=model_fn)
+
+    estimator.train(input_fn=input_fn, steps=10)
+    estimator.train(input_fn=input_fn, steps=10)
+    estimator.train(input_fn=input_fn, steps=10)
+    estimator.train(input_fn=input_fn, steps=10)
+
+
+if __name__ == '__main__':
+  test.main()
diff --git a/tensorflow/core/platform/windows/BUILD b/tensorflow/core/platform/windows/BUILD
index caba7db0d61..dddb4b9aed4 100644
--- a/tensorflow/core/platform/windows/BUILD
+++ b/tensorflow/core/platform/windows/BUILD
@@ -24,6 +24,7 @@ cc_library(
         "//tensorflow/core/platform:env.cc",
         "//tensorflow/core/platform:file_system.cc",
         "//tensorflow/core/platform:file_system_helper.cc",
+        "//tensorflow/core/platform:ram_file_system.h",
         "//tensorflow/core/platform:threadpool.cc",
     ],
     hdrs = [
diff --git a/tensorflow/core/platform/windows/env.cc b/tensorflow/core/platform/windows/env.cc
index 843f41765ef..d75d2d5773d 100644
--- a/tensorflow/core/platform/windows/env.cc
+++ b/tensorflow/core/platform/windows/env.cc
@@ -31,6 +31,7 @@ limitations under the License.
 
 #include "tensorflow/core/platform/load_library.h"
 #include "tensorflow/core/platform/logging.h"
+#include "tensorflow/core/platform/ram_file_system.h"
 #include "tensorflow/core/platform/windows/wide_char.h"
 #include "tensorflow/core/platform/windows/windows_file_system.h"
 #include "tensorflow/core/protobuf/error_codes.pb.h"
@@ -192,6 +193,7 @@ class WindowsEnv : public Env {
 
 REGISTER_FILE_SYSTEM("", WindowsFileSystem);
 REGISTER_FILE_SYSTEM("file", LocalWinFileSystem);
+REGISTER_FILE_SYSTEM("ram", RamFileSystem);
 
 Env* Env::Default() {
   static Env* default_env = new WindowsEnv;