diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd6f2534..f625aa5c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,7 +17,8 @@
 - Add endpoints to show the watchers list for issues, tasks and user stories.
 - Add headers to allow threading for notification emails about changes to issues, tasks, user stories, and wiki pages. (thanks to [@brett](https://github.com/brettp)).
 - Add externall apps: now Taiga can integrate with hundreds of applications and service.
-- Improving searching system, now full text searchs are supported
+- Improve searching system, now full text searchs are supported
+- Improve export system, now is more efficient and  prevents possible crashes with heavy projects.
 - i18n.
   - Add italian (it) translation.
   - Add polish (pl) translation.
diff --git a/taiga/base/api/settings.py b/taiga/base/api/settings.py
index 69440ec0..34dd9717 100644
--- a/taiga/base/api/settings.py
+++ b/taiga/base/api/settings.py
@@ -117,7 +117,7 @@ DEFAULTS = {
     "DATE_INPUT_FORMATS": (
         ISO_8601,
     ),
-    "DATE_FORMAT": None,
+    "DATE_FORMAT": ISO_8601,
 
     "DATETIME_INPUT_FORMATS": (
         ISO_8601,
diff --git a/taiga/base/storage.py b/taiga/base/storage.py
index acf93306..35e234df 100644
--- a/taiga/base/storage.py
+++ b/taiga/base/storage.py
@@ -18,7 +18,7 @@ from django.conf import settings
 from django.core.files import storage
 
 import django_sites as sites
-
+import os
 
 class FileSystemStorage(storage.FileSystemStorage):
     def __init__(self, *args, **kwargs):
@@ -30,3 +30,33 @@ class FileSystemStorage(storage.FileSystemStorage):
             scheme = site.scheme and "{0}:".format(site.scheme) or ""
             self.base_url = url_tmpl.format(scheme=scheme, domain=site.domain,
                                             url=settings.MEDIA_URL)
+
+    def open(self, name, mode='rb'):
+        """
+        Let's create the needed directory structrue before opening the file
+        """
+
+        # Create any intermediate directories that do not exist.
+        # Note that there is a race between os.path.exists and os.makedirs:
+        # if os.makedirs fails with EEXIST, the directory was created
+        # concurrently, and we can continue normally. Refs #16082.
+        directory = os.path.dirname(name)
+        if not os.path.exists(directory):
+            try:
+                if self.directory_permissions_mode is not None:
+                    # os.makedirs applies the global umask, so we reset it,
+                    # for consistency with file_permissions_mode behavior.
+                    old_umask = os.umask(0)
+                    try:
+                        os.makedirs(directory, self.directory_permissions_mode)
+                    finally:
+                        os.umask(old_umask)
+                else:
+                    os.makedirs(directory)
+            except OSError as e:
+                if e.errno != errno.EEXIST:
+                    raise
+        if not os.path.isdir(directory):
+            raise IOError("%s exists and is not a directory." % directory)
+
+        return super().open(name, mode=mode)
diff --git a/taiga/base/utils/json.py b/taiga/base/utils/json.py
index 2f7ac2e5..40132b34 100644
--- a/taiga/base/utils/json.py
+++ b/taiga/base/utils/json.py
@@ -30,6 +30,8 @@ def loads(data):
         data = force_text(data)
     return json.loads(data)
 
+load = json.load
+
 # Some backward compatibility that should
 # be removed in near future.
 to_json = dumps
diff --git a/taiga/export_import/api.py b/taiga/export_import/api.py
index 48e8592c..6fabb96d 100644
--- a/taiga/export_import/api.py
+++ b/taiga/export_import/api.py
@@ -14,7 +14,6 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import json
 import codecs
 import uuid
 
@@ -26,6 +25,7 @@ from django.conf import settings
 from django.core.files.storage import default_storage
 from django.core.files.base import ContentFile
 
+from taiga.base.utils import json
 from taiga.base.decorators import detail_route, list_route
 from taiga.base import exceptions as exc
 from taiga.base import response
@@ -67,10 +67,10 @@ class ProjectExporterViewSet(mixins.ImportThrottlingPolicyMixin, GenericViewSet)
             return response.Accepted({"export_id": task.id})
 
         path = "exports/{}/{}-{}.json".format(project.pk, project.slug, uuid.uuid4().hex)
-        content = ContentFile(ExportRenderer().render(service.project_to_dict(project),
-                                                      renderer_context={"indent": 4}).decode('utf-8'))
+        storage_path = default_storage.path(path)
+        with default_storage.open(storage_path, mode="w") as outfile:
+            service.render_project(project, outfile)
 
-        default_storage.save(path, content)
         response_data = {
             "url": default_storage.url(path)
         }
diff --git a/taiga/export_import/management/commands/dump_project.py b/taiga/export_import/management/commands/dump_project.py
index 2ea0d7a3..9728d01c 100644
--- a/taiga/export_import/management/commands/dump_project.py
+++ b/taiga/export_import/management/commands/dump_project.py
@@ -18,7 +18,10 @@ from django.core.management.base import BaseCommand, CommandError
 
 from taiga.projects.models import Project
 from taiga.export_import.renderers import ExportRenderer
-from taiga.export_import.service import project_to_dict
+from taiga.export_import.service import render_project
+
+
+import resource
 
 
 class Command(BaseCommand):
@@ -34,6 +37,5 @@ class Command(BaseCommand):
             except Project.DoesNotExist:
                 raise CommandError('Project "%s" does not exist' % project_slug)
 
-            data = project_to_dict(project)
             with open('%s.json'%(project_slug), 'w') as outfile:
-                self.renderer.render_to_file(data, outfile, renderer_context=self.renderer_context)
+                render_project(project, outfile)
diff --git a/taiga/export_import/management/commands/load_dump.py b/taiga/export_import/management/commands/load_dump.py
index 4566cf88..14016c6e 100644
--- a/taiga/export_import/management/commands/load_dump.py
+++ b/taiga/export_import/management/commands/load_dump.py
@@ -19,8 +19,7 @@ from django.db import transaction
 from django.db.models import signals
 from optparse import make_option
 
-import json
-
+from taiga.base.utils import json
 from taiga.projects.models import Project
 from taiga.export_import.renderers import ExportRenderer
 from taiga.export_import.dump_service import dict_to_project, TaigaImportError
diff --git a/taiga/export_import/serializers.py b/taiga/export_import/serializers.py
index 9ea19705..02334510 100644
--- a/taiga/export_import/serializers.py
+++ b/taiga/export_import/serializers.py
@@ -494,6 +494,8 @@ class RolePointsExportSerializer(serializers.ModelSerializer):
 class MilestoneExportSerializer(WatcheableObjectModelSerializer):
     owner = UserRelatedField(required=False)
     modified_date = serializers.DateTimeField(required=False)
+    estimated_start = serializers.DateField(required=False)
+    estimated_finish = serializers.DateField(required=False)
 
     def __init__(self, *args, **kwargs):
         project = kwargs.pop('project', None)
diff --git a/taiga/export_import/service.py b/taiga/export_import/service.py
index 25b9be90..ef0b8a22 100644
--- a/taiga/export_import/service.py
+++ b/taiga/export_import/service.py
@@ -14,20 +14,28 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import uuid
+import base64
+import gc
+import resource
+import os
 import os.path as path
+import uuid
+
 from unidecode import unidecode
 
 from django.template.defaultfilters import slugify
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ObjectDoesNotExist
+from django.core.files.storage import default_storage
 
+from taiga.base.utils import json
 from taiga.projects.history.services import make_key_from_model_object, take_snapshot
 from taiga.timeline.service import build_project_namespace
 from taiga.projects.references import sequences as seq
 from taiga.projects.references import models as refs
 from taiga.projects.userstories.models import RolePoints
 from taiga.projects.services import find_invited_user
+from taiga.base.api.fields import get_component
 
 from . import serializers
 
@@ -48,8 +56,81 @@ def add_errors(section, errors):
         _errors_log[section] = [errors]
 
 
-def project_to_dict(project):
-    return serializers.ProjectExportSerializer(project).data
+def render_project(project, outfile, chunk_size = 8192):
+    serializer = serializers.ProjectExportSerializer(project)
+    outfile.write('{\n')
+
+    first_field = True
+    for field_name in serializer.fields.keys():
+        # Avoid writing "," in the last element
+        if not first_field:
+            outfile.write(",\n")
+        else:
+            first_field = False
+
+        field = serializer.fields.get(field_name)
+        field.initialize(parent=serializer, field_name=field_name)
+
+        # These four "special" fields hava attachments so we use them in a special way
+        if field_name in ["wiki_pages", "user_stories", "tasks", "issues"]:
+            value = get_component(project, field_name)
+            outfile.write('"{}": [\n'.format(field_name))
+
+            attachments_field = field.fields.pop("attachments", None)
+            if attachments_field:
+                attachments_field.initialize(parent=field, field_name="attachments")
+
+            first_item = True
+            for item in value.iterator():
+                # Avoid writing "," in the last element
+                if not first_item:
+                    outfile.write(",\n")
+                else:
+                    first_item = False
+
+
+                dumped_value = json.dumps(field.to_native(item))
+                writing_value = dumped_value[:-1]+ ',\n    "attachments": [\n'
+                outfile.write(writing_value)
+
+                first_attachment = True
+                for attachment in item.attachments.iterator():
+                    # Avoid writing "," in the last element
+                    if not first_attachment:
+                        outfile.write(",\n")
+                    else:
+                        first_attachment = False
+
+                    # Write all the data expect the serialized file
+                    attachment_serializer = serializers.AttachmentExportSerializer(instance=attachment)
+                    attached_file_serializer = attachment_serializer.fields.pop("attached_file")
+                    dumped_value = json.dumps(attachment_serializer.data)
+                    dumped_value = dumped_value[:-1] + ',\n        "attached_file":{\n            "data":"'
+                    outfile.write(dumped_value)
+
+                    # We write the attached_files by chunks so the memory used is not increased
+                    attachment_file = attachment.attached_file
+                    with default_storage.open(attachment_file.name) as f:
+                        while True:
+                            bin_data = f.read(chunk_size)
+                            if not bin_data:
+                                break
+
+                            b64_data = base64.b64encode(bin_data).decode('utf-8')
+                            outfile.write(b64_data)
+
+                    outfile.write('", \n            "name":"{}"}}\n}}'.format(os.path.basename(attachment_file.name)))
+
+                outfile.write(']}')
+                outfile.flush()
+                gc.collect()
+            outfile.write(']')
+
+        else:
+            value = field.field_to_native(project, field_name)
+            outfile.write('"{}": {}'.format(field_name, json.dumps(value)))
+
+    outfile.write('}\n')
 
 
 def store_project(data):
diff --git a/taiga/export_import/tasks.py b/taiga/export_import/tasks.py
index 1698b9c4..f833aef4 100644
--- a/taiga/export_import/tasks.py
+++ b/taiga/export_import/tasks.py
@@ -29,25 +29,26 @@ from djmail.template_mail import MagicMailBuilder, InlineCSSTemplateMail
 
 from taiga.celery import app
 
-from .service import project_to_dict
+from .service import render_project
 from .dump_service import dict_to_project
 from .renderers import ExportRenderer
 
 logger = logging.getLogger('taiga.export_import')
 
+import resource
+
 
 @app.task(bind=True)
 def dump_project(self, user, project):
     mbuilder = MagicMailBuilder(template_mail_cls=InlineCSSTemplateMail)
     path = "exports/{}/{}-{}.json".format(project.pk, project.slug, self.request.id)
+    storage_path = default_storage.path(path)
 
     try:
-        content = ExportRenderer().render(project_to_dict(project), renderer_context={"indent": 4})
-        content = content.decode('utf-8')
-        content = ContentFile(content)
-
-        default_storage.save(path, content)
         url = default_storage.url(path)
+        with default_storage.open(storage_path, mode="w") as outfile:
+            render_project(project, outfile)
+
     except Exception:
         ctx = {
             "user": user,
diff --git a/tests/integration/test_importer_api.py b/tests/integration/test_importer_api.py
index a0f2219b..d8fe6f50 100644
--- a/tests/integration/test_importer_api.py
+++ b/tests/integration/test_importer_api.py
@@ -910,7 +910,6 @@ def test_valid_milestone_import(client):
     assert response.data["watchers"] == [user_watching.email]
 
 
-
 def test_milestone_import_duplicated_milestone(client):
     user = f.UserFactory.create()
     project = f.ProjectFactory.create(owner=user)
diff --git a/tests/unit/test_export.py b/tests/unit/test_export.py
index 67de6eac..0a6ba9d6 100644
--- a/tests/unit/test_export.py
+++ b/tests/unit/test_export.py
@@ -15,21 +15,29 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import pytest
-
+import io
 from .. import factories as f
 
-from taiga.export_import.service import project_to_dict
+from taiga.base.utils import json
+from taiga.export_import.service import render_project
 
 pytestmark = pytest.mark.django_db
 
 
 def test_export_issue_finish_date(client):
     issue = f.IssueFactory.create(finished_date="2014-10-22")
-    finish_date = project_to_dict(issue.project)["issues"][0]["finished_date"]
+    output = io.StringIO()
+    render_project(issue.project, output)
+    print(output.getvalue())
+    project_data = json.loads(output.getvalue())
+    finish_date = project_data["issues"][0]["finished_date"]
     assert finish_date == "2014-10-22T00:00:00+0000"
 
 
 def test_export_user_story_finish_date(client):
     user_story = f.UserStoryFactory.create(finish_date="2014-10-22")
-    finish_date = project_to_dict(user_story.project)["user_stories"][0]["finish_date"]
+    output = io.StringIO()
+    render_project(user_story.project, output)
+    project_data = json.loads(output.getvalue())
+    finish_date = project_data["user_stories"][0]["finish_date"]
     assert finish_date == "2014-10-22T00:00:00+0000"