diff --git a/rhodecode/api/views/user_api.py b/rhodecode/api/views/user_api.py
--- a/rhodecode/api/views/user_api.py
+++ b/rhodecode/api/views/user_api.py
@@ -19,6 +19,7 @@
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import logging
+from pyramid import compat
 
 from rhodecode.api import (
     jsonrpc_method, JSONRPCError, JSONRPCForbidden, JSONRPCValidationError)
@@ -241,7 +242,7 @@ def create_user(request, apiuser, userna
         # generate temporary password if user is external
         password = PasswordGenerator().gen_password(length=16)
     create_repo_group = Optional.extract(create_personal_repo_group)
-    if isinstance(create_repo_group, basestring):
+    if isinstance(create_repo_group, compat.string_types):
         create_repo_group = str2bool(create_repo_group)
 
     username = Optional.extract(username)
diff --git a/rhodecode/apps/_base/__init__.py b/rhodecode/apps/_base/__init__.py
--- a/rhodecode/apps/_base/__init__.py
+++ b/rhodecode/apps/_base/__init__.py
@@ -22,6 +22,7 @@ import time
 import logging
 import operator
 
+from pyramid import compat
 from pyramid.httpexceptions import HTTPFound, HTTPForbidden, HTTPBadRequest
 
 from rhodecode.lib import helpers as h, diffs
@@ -395,7 +396,7 @@ class DataGridAppView(object):
         return draw, start, length
 
     def _get_order_col(self, order_by, model):
-        if isinstance(order_by, basestring):
+        if isinstance(order_by, compat.string_types):
             try:
                 return operator.attrgetter(order_by)(model)
             except AttributeError:
diff --git a/rhodecode/apps/svn_support/__init__.py b/rhodecode/apps/svn_support/__init__.py
--- a/rhodecode/apps/svn_support/__init__.py
+++ b/rhodecode/apps/svn_support/__init__.py
@@ -17,10 +17,10 @@
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
-
+import os
 import logging
-import os
 import shlex
+from pyramid import compat
 
 # Do not use `from rhodecode import events` here, it will be overridden by the
 # events module in this package due to pythons import mechanism.
@@ -85,6 +85,6 @@ def _append_path_sep(path):
     """
     Append the path separator if missing.
     """
-    if isinstance(path, basestring) and not path.endswith(os.path.sep):
+    if isinstance(path, compat.string_types) and not path.endswith(os.path.sep):
         path += os.path.sep
     return path
diff --git a/rhodecode/lib/celerylib/tasks.py b/rhodecode/lib/celerylib/tasks.py
--- a/rhodecode/lib/celerylib/tasks.py
+++ b/rhodecode/lib/celerylib/tasks.py
@@ -26,6 +26,7 @@ by celery daemon
 import os
 import time
 
+from pyramid import compat
 from pyramid_mailer.mailer import Mailer
 from pyramid_mailer.message import Message
 
@@ -62,7 +63,7 @@ def send_email(recipients, subject, body
     subject = "%s %s" % (email_config.get('email_prefix', ''), subject)
 
     if recipients:
-        if isinstance(recipients, basestring):
+        if isinstance(recipients, compat.string_types):
             recipients = recipients.split(',')
     else:
         # if recipients are not defined we send to email_config + all admins
diff --git a/rhodecode/lib/codeblocks.py b/rhodecode/lib/codeblocks.py
--- a/rhodecode/lib/codeblocks.py
+++ b/rhodecode/lib/codeblocks.py
@@ -26,6 +26,7 @@ from pygments import lex
 from pygments.formatters.html import _get_ttype_class as pygment_token_class
 from pygments.lexers.special import TextLexer, Token
 from pygments.lexers import get_lexer_by_name
+from pyramid import compat
 
 from rhodecode.lib.helpers import (
     get_lexer_for_filenode, html_escape, get_custom_lexer)
@@ -695,7 +696,7 @@ class DiffSet(object):
         filenode = None
         filename = None
 
-        if isinstance(input_file, basestring):
+        if isinstance(input_file, compat.string_types):
             filename = input_file
         elif isinstance(input_file, FileNode):
             filenode = input_file
diff --git a/rhodecode/lib/colander_utils.py b/rhodecode/lib/colander_utils.py
--- a/rhodecode/lib/colander_utils.py
+++ b/rhodecode/lib/colander_utils.py
@@ -18,13 +18,15 @@
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
+from pyramid import compat
+
 
 def strip_whitespace(value):
     """
     Removes leading/trailing whitespace, newlines, and tabs from the value.
     Implements the `colander.interface.Preparer` interface.
     """
-    if isinstance(value, basestring):
+    if isinstance(value, compat.string_types):
         return value.strip(' \t\n\r')
     else:
         return value
diff --git a/rhodecode/lib/dbmigrate/migrate/changeset/schema.py b/rhodecode/lib/dbmigrate/migrate/changeset/schema.py
--- a/rhodecode/lib/dbmigrate/migrate/changeset/schema.py
+++ b/rhodecode/lib/dbmigrate/migrate/changeset/schema.py
@@ -9,6 +9,7 @@ import sqlalchemy
 
 from sqlalchemy.schema import ForeignKeyConstraint
 from sqlalchemy.schema import UniqueConstraint
+from pyramid import compat
 
 from rhodecode.lib.dbmigrate.migrate.exceptions import *
 from rhodecode.lib.dbmigrate.migrate.changeset import SQLA_07, SQLA_08
@@ -229,7 +230,7 @@ class ColumnDelta(DictMixin, sqlalchemy.
                 diffs = self.compare_1_column(*p, **kw)
         else:
             # Zero columns specified
-            if not len(p) or not isinstance(p[0], basestring):
+            if not len(p) or not isinstance(p[0], compat.string_types):
                 raise ValueError("First argument must be column name")
             diffs = self.compare_parameters(*p, **kw)
 
@@ -338,7 +339,7 @@ class ColumnDelta(DictMixin, sqlalchemy.
         """Extracts data from p and modifies diffs"""
         p = list(p)
         while len(p):
-            if isinstance(p[0], basestring):
+            if isinstance(p[0], compat.string_types):
                 k.setdefault('name', p.pop(0))
             elif isinstance(p[0], sqlalchemy.types.TypeEngine):
                 k.setdefault('type', p.pop(0))
@@ -376,7 +377,7 @@ class ColumnDelta(DictMixin, sqlalchemy.
         return getattr(self, '_table', None)
 
     def _set_table(self, table):
-        if isinstance(table, basestring):
+        if isinstance(table, compat.string_types):
             if self.alter_metadata:
                 if not self.meta:
                     raise ValueError("metadata must be specified for table"
@@ -593,7 +594,7 @@ populated with defaults
             if isinstance(cons,(ForeignKeyConstraint,
                                 UniqueConstraint)):
                 for col_name in cons.columns:
-                    if not isinstance(col_name,basestring):
+                    if not isinstance(col_name, compat.string_types):
                         col_name = col_name.name
                     if self.name==col_name:
                         to_drop.add(cons)
@@ -628,7 +629,7 @@ populated with defaults
         if (getattr(self, name[:-5]) and not obj):
             raise InvalidConstraintError("Column.create() accepts index_name,"
             " primary_key_name and unique_name to generate constraints")
-        if not isinstance(obj, basestring) and obj is not None:
+        if not isinstance(obj, compat.string_types) and obj is not None:
             raise InvalidConstraintError(
             "%s argument for column must be constraint name" % name)
 
diff --git a/rhodecode/lib/dbmigrate/migrate/versioning/schema.py b/rhodecode/lib/dbmigrate/migrate/versioning/schema.py
--- a/rhodecode/lib/dbmigrate/migrate/versioning/schema.py
+++ b/rhodecode/lib/dbmigrate/migrate/versioning/schema.py
@@ -9,6 +9,7 @@ from sqlalchemy import (Table, Column, M
 from sqlalchemy.sql import and_
 from sqlalchemy import exc as sa_exceptions
 from sqlalchemy.sql import bindparam
+from pyramid import compat
 
 from rhodecode.lib.dbmigrate.migrate import exceptions
 from rhodecode.lib.dbmigrate.migrate.changeset import SQLA_07
@@ -25,7 +26,7 @@ class ControlledSchema(object):
     """A database under version control"""
 
     def __init__(self, engine, repository):
-        if isinstance(repository, basestring):
+        if isinstance(repository, compat.string_types):
             repository = Repository(repository)
         self.engine = engine
         self.repository = repository
@@ -134,7 +135,7 @@ class ControlledSchema(object):
         """
         # Confirm that the version # is valid: positive, integer,
         # exists in repos
-        if isinstance(repository, basestring):
+        if isinstance(repository, compat.string_types):
             repository = Repository(repository)
         version = cls._validate_version(repository, version)
         table = cls._create_table_version(engine, repository, version)
@@ -199,7 +200,7 @@ class ControlledSchema(object):
         """
         Compare the current model against the current database.
         """
-        if isinstance(repository, basestring):
+        if isinstance(repository, compat.string_types):
             repository = Repository(repository)
         model = load_model(model)
 
@@ -212,7 +213,7 @@ class ControlledSchema(object):
         """
         Dump the current database as a Python model.
         """
-        if isinstance(repository, basestring):
+        if isinstance(repository, compat.string_types):
             repository = Repository(repository)
 
         diff = schemadiff.getDiffOfModelAgainstDatabase(
diff --git a/rhodecode/lib/dbmigrate/migrate/versioning/script/py.py b/rhodecode/lib/dbmigrate/migrate/versioning/script/py.py
--- a/rhodecode/lib/dbmigrate/migrate/versioning/script/py.py
+++ b/rhodecode/lib/dbmigrate/migrate/versioning/script/py.py
@@ -7,6 +7,7 @@ import logging
 import inspect
 from StringIO import StringIO
 
+from pyramid import compat
 from rhodecode.lib.dbmigrate import migrate
 from rhodecode.lib.dbmigrate.migrate.versioning import genmodel, schemadiff
 from rhodecode.lib.dbmigrate.migrate.versioning.config import operations
@@ -51,7 +52,7 @@ class PythonScript(base.BaseScript):
         :rtype: string
         """
 
-        if isinstance(repository, basestring):
+        if isinstance(repository, compat.string_types):
             # oh dear, an import cycle!
             from rhodecode.lib.dbmigrate.migrate.versioning.repository import Repository
             repository = Repository(repository)
diff --git a/rhodecode/lib/dbmigrate/migrate/versioning/util/__init__.py b/rhodecode/lib/dbmigrate/migrate/versioning/util/__init__.py
--- a/rhodecode/lib/dbmigrate/migrate/versioning/util/__init__.py
+++ b/rhodecode/lib/dbmigrate/migrate/versioning/util/__init__.py
@@ -11,6 +11,7 @@ from sqlalchemy import create_engine
 from sqlalchemy.engine import Engine
 from sqlalchemy.pool import StaticPool
 
+from pyramid import compat
 from rhodecode.lib.dbmigrate.migrate import exceptions
 from rhodecode.lib.dbmigrate.migrate.versioning.util.keyedinstance import KeyedInstance
 from rhodecode.lib.dbmigrate.migrate.versioning.util.importpath import import_path
@@ -18,6 +19,7 @@ from rhodecode.lib.dbmigrate.migrate.ver
 
 log = logging.getLogger(__name__)
 
+
 def load_model(dotted_name):
     """Import module and use module-level variable".
 
@@ -26,7 +28,7 @@ def load_model(dotted_name):
     .. versionchanged:: 0.5.4
 
     """
-    if isinstance(dotted_name, basestring):
+    if isinstance(dotted_name, compat.string_types):
         if ':' not in dotted_name:
             # backwards compatibility
             warnings.warn('model should be in form of module.model:User '
@@ -39,7 +41,7 @@ def load_model(dotted_name):
 
 def asbool(obj):
     """Do everything to use object as bool"""
-    if isinstance(obj, basestring):
+    if isinstance(obj, compat.string_types):
         obj = obj.strip().lower()
         if obj in ['true', 'yes', 'on', 'y', 't', '1']:
             return True
@@ -112,7 +114,7 @@ def construct_engine(engine, **opts):
     """
     if isinstance(engine, Engine):
         return engine
-    elif not isinstance(engine, basestring):
+    elif not isinstance(engine, compat.string_types):
         raise ValueError("you need to pass either an existing engine or a database uri")
 
     # get options for create_engine
diff --git a/rhodecode/lib/dbmigrate/schema/db_1_2_0.py b/rhodecode/lib/dbmigrate/schema/db_1_2_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_1_2_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_1_2_0.py
@@ -28,6 +28,7 @@ from sqlalchemy import *
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import relationship, joinedload, class_mapper, validates
 from beaker.cache import cache_region, region_invalidate
+from pyramid import compat
 
 from rhodecode.lib.vcs import get_backend
 from rhodecode.lib.vcs.utils.helpers import get_scm
@@ -413,7 +414,7 @@ class UserGroup(Base, BaseModel):
                     Session.flush()
                     members_list = []
                     if v:
-                        v = [v] if isinstance(v, basestring) else v
+                        v = [v] if isinstance(v, compat.string_types) else v
                         for u_id in set(v):
                             member = UserGroupMember(users_group_id, u_id)
                             members_list.append(member)
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_11_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_11_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_11_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_11_0_0.py
@@ -49,7 +49,7 @@ from sqlalchemy.exc import IntegrityErro
 from sqlalchemy.dialects.mysql import LONGTEXT
 from beaker.cache import cache_region
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2110,7 +2110,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3726,7 +3726,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_13_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_13_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_13_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_13_0_0.py
@@ -49,7 +49,7 @@ from sqlalchemy.exc import IntegrityErro
 from sqlalchemy.dialects.mysql import LONGTEXT
 from beaker.cache import cache_region
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2176,7 +2176,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3809,7 +3809,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_16_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_16_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_16_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_16_0_0.py
@@ -48,7 +48,7 @@ from sqlalchemy.ext.hybrid import hybrid
 from sqlalchemy.exc import IntegrityError  # pragma: no cover
 from sqlalchemy.dialects.mysql import LONGTEXT
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2217,7 +2217,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3957,7 +3957,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_16_0_1.py b/rhodecode/lib/dbmigrate/schema/db_4_16_0_1.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_16_0_1.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_16_0_1.py
@@ -48,7 +48,7 @@ from sqlalchemy.ext.hybrid import hybrid
 from sqlalchemy.exc import IntegrityError  # pragma: no cover
 from sqlalchemy.dialects.mysql import LONGTEXT
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2240,7 +2240,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -4031,7 +4031,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_3_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_3_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_3_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_3_0_0.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declared_attr
@@ -45,6 +44,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region, region_invalidate
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
+from pyramid import compat
 
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
@@ -1811,7 +1811,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_4_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_4_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_4_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_4_0_0.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declared_attr
@@ -45,6 +44,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region, region_invalidate
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
+from pyramid import compat
 
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
@@ -1814,7 +1814,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_4_0_1.py b/rhodecode/lib/dbmigrate/schema/db_4_4_0_1.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_4_0_1.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_4_0_1.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declared_attr
@@ -45,7 +44,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region, region_invalidate
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
 from rhodecode.translation import _
@@ -1814,7 +1813,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_4_0_2.py b/rhodecode/lib/dbmigrate/schema/db_4_4_0_2.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_4_0_2.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_4_0_2.py
@@ -35,7 +35,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declared_attr
@@ -46,7 +45,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region, region_invalidate
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
 from rhodecode.translation import _
@@ -1816,7 +1815,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_5_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_5_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_5_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_5_0_0.py
@@ -35,7 +35,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declared_attr
@@ -46,7 +45,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region, region_invalidate
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
 from rhodecode.translation import _
@@ -1816,7 +1815,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3180,7 +3179,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_7_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_7_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_7_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_7_0_0.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.ext.declarative import declared_attr
 from sqlalchemy.ext.hybrid import hybrid_property
@@ -44,6 +43,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
+from pyramid import compat
 
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
@@ -1858,7 +1858,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3407,7 +3407,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_7_0_1.py b/rhodecode/lib/dbmigrate/schema/db_4_7_0_1.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_7_0_1.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_7_0_1.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.ext.declarative import declared_attr
 from sqlalchemy.ext.hybrid import hybrid_property
@@ -44,6 +43,7 @@ from sqlalchemy.sql.expression import tr
 from beaker.cache import cache_region
 from webob.exc import HTTPNotFound
 from zope.cachedescriptors.property import Lazy as LazyProperty
+from pyramid import compat
 
 # replace pylons with fake url for migration
 from rhodecode.lib.dbmigrate.schema import url
@@ -1859,7 +1859,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3408,7 +3408,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/schema/db_4_9_0_0.py b/rhodecode/lib/dbmigrate/schema/db_4_9_0_0.py
--- a/rhodecode/lib/dbmigrate/schema/db_4_9_0_0.py
+++ b/rhodecode/lib/dbmigrate/schema/db_4_9_0_0.py
@@ -34,7 +34,6 @@ import functools
 import traceback
 import collections
 
-
 from sqlalchemy import *
 from sqlalchemy.ext.declarative import declared_attr
 from sqlalchemy.ext.hybrid import hybrid_property
@@ -44,7 +43,7 @@ from sqlalchemy.sql.expression import tr
 from sqlalchemy.sql.functions import coalesce, count  # pragma: no cover
 from beaker.cache import cache_region
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2047,7 +2046,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -3662,7 +3661,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/lib/dbmigrate/versions/070_version_4_7_0.py b/rhodecode/lib/dbmigrate/versions/070_version_4_7_0.py
--- a/rhodecode/lib/dbmigrate/versions/070_version_4_7_0.py
+++ b/rhodecode/lib/dbmigrate/versions/070_version_4_7_0.py
@@ -2,6 +2,7 @@ import logging
 import datetime
 
 from sqlalchemy import *
+from pyramid import compat
 
 from rhodecode.lib.utils2 import safe_str
 from rhodecode.model import meta
@@ -12,7 +13,7 @@ log = logging.getLogger(__name__)
 
 def time_to_datetime(tm):
     if tm:
-        if isinstance(tm, basestring):
+        if isinstance(tm, compat.string_types):
             try:
                 tm = float(tm)
             except ValueError:
diff --git a/rhodecode/lib/diff_match_patch.py b/rhodecode/lib/diff_match_patch.py
--- a/rhodecode/lib/diff_match_patch.py
+++ b/rhodecode/lib/diff_match_patch.py
@@ -1,4 +1,3 @@
-#!/usr/bin/python2.4
 
 from __future__ import division
 
@@ -33,6 +32,8 @@ import re
 import sys
 import time
 import urllib
+from pyramid import compat
+
 
 class diff_match_patch:
   """Class containing the diff, match and patch methods.
@@ -1438,7 +1439,7 @@ class diff_match_patch:
     text1 = None
     diffs = None
     # Note that texts may arrive as 'str' or 'unicode'.
-    if isinstance(a, basestring) and isinstance(b, basestring) and c is None:
+    if isinstance(a, compat.string_types) and isinstance(b, compat.string_types) and c is None:
       # Method 1: text1, text2
       # Compute diffs from text1 and text2.
       text1 = a
@@ -1451,11 +1452,11 @@ class diff_match_patch:
       # Compute text1 from diffs.
       diffs = a
       text1 = self.diff_text1(diffs)
-    elif isinstance(a, basestring) and isinstance(b, list) and c is None:
+    elif isinstance(a, compat.string_types) and isinstance(b, list) and c is None:
       # Method 3: text1, diffs
       text1 = a
       diffs = b
-    elif (isinstance(a, basestring) and isinstance(b, basestring) and
+    elif (isinstance(a, compat.string_types) and isinstance(b, compat.string_types) and
           isinstance(c, list)):
       # Method 4: text1, text2, diffs
       # text2 is not used.
diff --git a/rhodecode/lib/helpers.py b/rhodecode/lib/helpers.py
--- a/rhodecode/lib/helpers.py
+++ b/rhodecode/lib/helpers.py
@@ -34,7 +34,6 @@ import urllib
 import math
 import logging
 import re
-import urlparse
 import time
 import string
 import hashlib
@@ -45,6 +44,7 @@ import itertools
 import fnmatch
 import bleach
 
+from pyramid import compat
 from datetime import datetime
 from functools import partial
 from pygments.formatters.html import HtmlFormatter
diff --git a/rhodecode/lib/rc_cache/utils.py b/rhodecode/lib/rc_cache/utils.py
--- a/rhodecode/lib/rc_cache/utils.py
+++ b/rhodecode/lib/rc_cache/utils.py
@@ -120,7 +120,7 @@ def get_default_cache_settings(settings,
             if key.startswith(prefix):
                 name = key.split(prefix)[1].strip()
                 val = settings[key]
-                if isinstance(val, basestring):
+                if isinstance(val, compat.string_types):
                     val = val.strip()
                 cache_settings[name] = val
     return cache_settings
diff --git a/rhodecode/lib/utils2.py b/rhodecode/lib/utils2.py
--- a/rhodecode/lib/utils2.py
+++ b/rhodecode/lib/utils2.py
@@ -43,6 +43,7 @@ import sqlalchemy.exc
 import sqlalchemy.sql
 import webob
 import pyramid.threadlocal
+from pyramid import compat
 from pyramid.settings import asbool
 
 import rhodecode
@@ -261,7 +262,7 @@ def safe_str(unicode_, to_encoding=None)
     """
 
     # if it's not basestr cast to str
-    if not isinstance(unicode_, basestring):
+    if not isinstance(unicode_, compat.string_types):
         return str(unicode_)
 
     if isinstance(unicode_, str):
@@ -687,7 +688,7 @@ def datetime_to_time(dt):
 
 def time_to_datetime(tm):
     if tm:
-        if isinstance(tm, basestring):
+        if isinstance(tm, compat.string_types):
             try:
                 tm = float(tm)
             except ValueError:
@@ -697,7 +698,7 @@ def time_to_datetime(tm):
 
 def time_to_utcdatetime(tm):
     if tm:
-        if isinstance(tm, basestring):
+        if isinstance(tm, compat.string_types):
             try:
                 tm = float(tm)
             except ValueError:
diff --git a/rhodecode/lib/vcs/backends/base.py b/rhodecode/lib/vcs/backends/base.py
--- a/rhodecode/lib/vcs/backends/base.py
+++ b/rhodecode/lib/vcs/backends/base.py
@@ -33,6 +33,7 @@ import collections
 import warnings
 
 from zope.cachedescriptors.property import Lazy as LazyProperty
+from pyramid import compat
 
 from rhodecode.translation import lazy_ugettext
 from rhodecode.lib.utils2 import safe_str, safe_unicode
@@ -692,7 +693,7 @@ class BaseRepository(object):
                 (commit, self, commit.repository))
 
     def _validate_commit_id(self, commit_id):
-        if not isinstance(commit_id, basestring):
+        if not isinstance(commit_id, compat.string_types):
             raise TypeError("commit_id must be a string value")
 
     def _validate_commit_idx(self, commit_idx):
@@ -729,7 +730,7 @@ class BaseRepository(object):
         warnings.warn("Use get_commit instead", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(revision, basestring):
+        if isinstance(revision, compat.string_types):
             commit_id = revision
         else:
             commit_idx = revision
@@ -756,7 +757,7 @@ class BaseRepository(object):
         if revision is None:
             return revision
 
-        if isinstance(revision, basestring):
+        if isinstance(revision, compat.string_types):
             commit_id = revision
         else:
             commit_id = self.commit_ids[revision]
diff --git a/rhodecode/lib/vcs/exceptions.py b/rhodecode/lib/vcs/exceptions.py
--- a/rhodecode/lib/vcs/exceptions.py
+++ b/rhodecode/lib/vcs/exceptions.py
@@ -25,6 +25,7 @@ import logging
 import functools
 import urllib2
 import rhodecode
+from pyramid import compat
 
 log = logging.getLogger(__name__)
 
@@ -191,7 +192,7 @@ def map_vcs_exceptions(func):
             org_remote_tb = getattr(e, '_vcs_server_org_exc_tb', '')
             __traceback_info__ = None
             if remote_tb:
-                if isinstance(remote_tb, basestring):
+                if isinstance(remote_tb, compat.string_types):
                     remote_tb = [remote_tb]
                 __traceback_info__ = (
                     'Found VCSServer remote traceback information:\n'
diff --git a/rhodecode/model/db.py b/rhodecode/model/db.py
--- a/rhodecode/model/db.py
+++ b/rhodecode/model/db.py
@@ -48,7 +48,7 @@ from sqlalchemy.ext.hybrid import hybrid
 from sqlalchemy.exc import IntegrityError  # pragma: no cover
 from sqlalchemy.dialects.mysql import LONGTEXT
 from zope.cachedescriptors.property import Lazy as LazyProperty
-
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode.translation import _
@@ -2240,7 +2240,7 @@ class Repository(Base, BaseModel):
         warnings.warn("Use get_commit", DeprecationWarning)
         commit_id = None
         commit_idx = None
-        if isinstance(rev, basestring):
+        if isinstance(rev, compat.string_types):
             commit_id = rev
         else:
             commit_idx = rev
@@ -4031,7 +4031,7 @@ class PullRequestReviewers(Base, BaseMod
     @reasons.setter
     def reasons(self, val):
         val = val or []
-        if any(not isinstance(x, basestring) for x in val):
+        if any(not isinstance(x, compat.string_types) for x in val):
             raise Exception('invalid reasons type, must be list of strings')
         self._reasons = val
 
diff --git a/rhodecode/model/pull_request.py b/rhodecode/model/pull_request.py
--- a/rhodecode/model/pull_request.py
+++ b/rhodecode/model/pull_request.py
@@ -30,6 +30,7 @@ import datetime
 import urllib
 import collections
 
+from pyramid import compat
 from pyramid.threadlocal import get_current_request
 
 from rhodecode import events
@@ -1001,7 +1002,7 @@ class PullRequestModel(BaseModel):
 
         reviewers = {}
         for user_id, reasons, mandatory, rules in reviewer_data:
-            if isinstance(user_id, (int, basestring)):
+            if isinstance(user_id, (int, compat.string_types)):
                 user_id = self._get_user(user_id).user_id
             reviewers[user_id] = {
                 'reasons': reasons, 'mandatory': mandatory}
diff --git a/rhodecode/model/user_group.py b/rhodecode/model/user_group.py
--- a/rhodecode/model/user_group.py
+++ b/rhodecode/model/user_group.py
@@ -20,6 +20,7 @@
 
 import logging
 import traceback
+from pyramid import compat
 
 from rhodecode.lib.utils2 import safe_str, safe_unicode
 from rhodecode.lib.exceptions import (
@@ -247,7 +248,7 @@ class UserGroupModel(BaseModel):
         # handle owner change
         if 'user' in form_data:
             owner = form_data['user']
-            if isinstance(owner, basestring):
+            if isinstance(owner, compat.string_types):
                 owner = User.get_by_username(form_data['user'])
 
             if not isinstance(owner, User):
diff --git a/rhodecode/model/validation_schema/preparers.py b/rhodecode/model/validation_schema/preparers.py
--- a/rhodecode/model/validation_schema/preparers.py
+++ b/rhodecode/model/validation_schema/preparers.py
@@ -19,6 +19,7 @@
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import unicodedata
+from pyramid import compat
 
 
 def strip_preparer(value):
@@ -83,6 +84,6 @@ def unique_list_from_str_preparer(value)
     """
     from rhodecode.lib.utils2 import aslist
 
-    if isinstance(value, basestring):
+    if isinstance(value, compat.string_types):
         value = aslist(value, ',')
     return unique_list_preparer(value)
\ No newline at end of file
diff --git a/rhodecode/model/validation_schema/types.py b/rhodecode/model/validation_schema/types.py
--- a/rhodecode/model/validation_schema/types.py
+++ b/rhodecode/model/validation_schema/types.py
@@ -21,6 +21,8 @@
 import re
 
 import colander
+from pyramid import compat
+
 from rhodecode.model.validation_schema import preparers
 from rhodecode.model.db import User, UserGroup
 
@@ -106,7 +108,7 @@ class StringBooleanType(colander.String)
         if isinstance(cstruct, bool):
             return cstruct
 
-        if not isinstance(cstruct, basestring):
+        if not isinstance(cstruct, compat.string_types):
             raise colander.Invalid(node, '%r is not a string' % cstruct)
 
         value = cstruct.lower()
@@ -190,7 +192,7 @@ class UserGroupType(UserOrUserGroupType)
 
 class StrOrIntType(colander.String):
     def deserialize(self, node, cstruct):
-        if isinstance(cstruct, basestring):
+        if isinstance(cstruct, compat.string_types):
             return super(StrOrIntType, self).deserialize(node, cstruct)
         else:
             return colander.Integer().deserialize(node, cstruct)
diff --git a/rhodecode/model/validators.py b/rhodecode/model/validators.py
--- a/rhodecode/model/validators.py
+++ b/rhodecode/model/validators.py
@@ -37,6 +37,7 @@ from formencode.validators import (
 
 from sqlalchemy.sql.expression import true
 from sqlalchemy.util import OrderedSet
+from pyramid import compat
 
 from rhodecode.authentication import (
     legacy_plugin_prefix, _import_legacy_plugin)
@@ -125,7 +126,7 @@ def UniqueListFromString(localizer):
 
     class _validator(UniqueList(localizer)):
         def _to_python(self, value, state):
-            if isinstance(value, basestring):
+            if isinstance(value, compat.string_types):
                 value = aslist(value, ',')
             return super(_validator, self)._to_python(value, state)
     return _validator
diff --git a/rhodecode/templates/codeblocks/diffs.mako b/rhodecode/templates/codeblocks/diffs.mako
--- a/rhodecode/templates/codeblocks/diffs.mako
+++ b/rhodecode/templates/codeblocks/diffs.mako
@@ -520,7 +520,7 @@ def get_comments_for(diff_type, comments
     if hasattr(filename, 'unicode_path'):
         filename = filename.unicode_path
 
-    if not isinstance(filename, basestring):
+    if not isinstance(filename, (unicode, str)):
         return None
 
     line_key = '{}{}'.format(line_version, line_number) ## e.g o37, n12
diff --git a/rhodecode/tests/config/test_utils.py b/rhodecode/tests/config/test_utils.py
--- a/rhodecode/tests/config/test_utils.py
+++ b/rhodecode/tests/config/test_utils.py
@@ -19,6 +19,7 @@
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import pytest
+from pyramid import compat
 
 from rhodecode.config.utils import set_instance_id
 
@@ -31,6 +32,6 @@ def test_set_instance_id(instance_id):
     if instance_id == 'custom-id':
         assert config['instance_id'] == instance_id
     else:
-        assert isinstance(config['instance_id'], basestring)
+        assert isinstance(config['instance_id'], compat.string_types)
         assert len(config['instance_id'])
         assert instance_id != config['instance_id']
diff --git a/rhodecode/tests/scripts/test_crawler.py b/rhodecode/tests/scripts/test_crawler.py
--- a/rhodecode/tests/scripts/test_crawler.py
+++ b/rhodecode/tests/scripts/test_crawler.py
@@ -35,7 +35,7 @@ import os
 import sys
 from os.path import join as jn
 from os.path import dirname as dn
-
+from pyramid import compat
 from sqlalchemy.util import OrderedSet
 
 __here__ = os.path.abspath(__file__)
@@ -77,7 +77,7 @@ urllib2.install_opener(o)
 
 
 def _get_repo(proj):
-    if isinstance(proj, basestring):
+    if isinstance(proj, compat.string_types):
         repo = vcs.get_repo(jn(PROJECT_PATH, proj))
         proj = proj
     else: