diff --git a/.pylintrc b/.pylintrc
new file mode 100644
index 0000000..6669789
--- /dev/null
+++ b/.pylintrc
@@ -0,0 +1,372 @@
+[MASTER]
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+#init-hook=
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=pylint.extensions.bad_builtin,pylint.extensions.check_elif,pylint.extensions.comparetozero,pylint.extensions.docparams,pylint.extensions.docstyle,pylint.extensions.emptystring,pylint.extensions.overlapping_exceptions,pylint.extensions.redefined_variable_type,pylint.extensions.mccabe
+
+# Use multiple processes to speed up Pylint.
+jobs=2
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code
+extension-pkg-whitelist=
+
+# Allow optimization of some AST trees. This will activate a peephole AST
+# optimizer, which will apply various small optimizations. For instance, it can
+# be used to obtain the result of joining multiple strings with the addition
+# operator. Joining a lot of strings can lead to a maximum recursion error in
+# Pylint and this flag can prevent that. It has one side effect, the resulting
+# AST will be different than the one from reality. This option is deprecated
+# and it will be removed in Pylint 2.0.
+optimize-ast=no
+
+
+[MESSAGES CONTROL]
+enable=all
+disable=I,fixme,missing-yield-doc,missing-yield-type-doc
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+output-format=parseable
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]". This option is deprecated
+# and it will be removed in Pylint 2.0.
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=yes
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[BASIC]
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=app,db,security,users_roles
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=foo,bar,baz,toto,tutu,tata
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Include a hint for the correct naming format with invalid-name
+include-naming-hint=yes
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+property-classes=abc.abstractproperty,sqlalchemy.util.hybridproperty,alembic.op
+
+# Regular expression matching correct variable names
+variable-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for variable names
+variable-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct attribute names
+attr-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for attribute names
+attr-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct function names
+function-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for function names
+function-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct class names
+class-rgx=[A-Z_][a-zA-Z0-9]+$
+
+# Naming hint for class names
+class-name-hint=[A-Z_][a-zA-Z0-9]+$
+
+# Regular expression matching correct method names
+method-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for method names
+method-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct argument names
+argument-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Naming hint for argument names
+argument-name-hint=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression matching correct module names
+module-rgx=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Naming hint for module names
+module-name-hint=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Regular expression matching correct class attribute names
+class-attribute-rgx=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
+
+# Naming hint for class attribute names
+class-attribute-name-hint=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
+
+# Regular expression matching correct constant names
+const-rgx=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Naming hint for constant names
+const-name-hint=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Regular expression matching correct inline iteration names
+inlinevar-rgx=[A-Za-z_][A-Za-z0-9_]*$
+
+# Naming hint for inline iteration names
+inlinevar-name-hint=[A-Za-z_][A-Za-z0-9_]*$
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=^_
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=-1
+
+
+[ELIF]
+
+# Maximum number of nested blocks for function / method body
+max-nested-blocks=5
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the name of dummy variables (i.e. expectedly
+# not used).
+dummy-variables-rgx=(_+[a-zA-Z0-9]*?$)|dummy
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,_cb
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six.moves,future.builtins
+
+
+[TYPECHECK]
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=flask_sqlalchemy,sqlalchemy.orm.scoping,numpy
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager
+
+
+[LOGGING]
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format
+logging-modules=logging
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=FIXME,XXX,TODO
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=100
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=^\s*(# )?<?https?://\S+>?$
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=no
+
+# List of optional constructs for which whitespace checking is disabled. `dict-
+# separator` is used to allow tabulation in dicts, etc.: {1  : 1,\n222: 2}.
+# `trailing-comma` allows a space between comma and closing bracket: (a, ).
+# `empty-line` allows space-only lines.
+no-space-check=trailing-comma,dict-separator
+
+# Maximum number of lines in a module
+max-module-lines=1000
+
+# String used as indentation unit. This is usually "    " (4 spaces) or "\t" (1
+# tab).
+indent-string='    '
+
+# Number of spaces of indent required inside a hanging  or continued line.
+indent-after-paren=4
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+
+[SPELLING]
+
+# Spelling dictionary name. Available dictionaries: none. To make it working
+# install python-enchant package.
+spelling-dict=
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to indicated private dictionary in
+# --spelling-private-dict-file option instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[DESIGN]
+
+# Maximum number of arguments for function / method
+max-args=5
+
+# Argument names that match this expression will be ignored. Default to name
+# with leading underscore
+ignored-argument-names=_.*
+
+# Maximum number of locals for function / method body
+max-locals=15
+
+# Maximum number of return / yield for function / method body
+max-returns=6
+
+# Maximum number of branch for function / method body
+max-branches=12
+
+# Maximum number of statements in function / method body
+max-statements=50
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+# Maximum number of boolean expressions in a if statement
+max-bool-expr=5
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,__new__,setUp
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,_fields,_replace,_source,_make
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=optparse
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant,numpy
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=Exception
diff --git a/Pipfile b/Pipfile
index 87a8e5c..0df03ea 100644
--- a/Pipfile
+++ b/Pipfile
@@ -15,6 +15,7 @@ flask-babelex = "*"
 python-dateutil = "*"
 
 [dev-packages]
+pylint = "*"
 
 [requires]
 python_version = "3.6"
diff --git a/Pipfile.lock b/Pipfile.lock
index b813a4c..83f8e02 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "6a3ccbef568786e9db9f07399ebc254400d2aede9986ce7c69090f2d0c250037"
+            "sha256": "87b2f3f49611403e69ea47ebc364bf471ab966577dcf0f813087fe7f386bc75e"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -268,5 +268,83 @@
             "version": "==2.2.1"
         }
     },
-    "develop": {}
+    "develop": {
+        "astroid": {
+            "hashes": [
+                "sha256:0ef2bf9f07c3150929b25e8e61b5198c27b0dca195e156f0e4d5bdd89185ca1a",
+                "sha256:fc9b582dba0366e63540982c3944a9230cbc6f303641c51483fa547dcc22393a"
+            ],
+            "version": "==1.6.5"
+        },
+        "isort": {
+            "hashes": [
+                "sha256:1153601da39a25b14ddc54955dbbacbb6b2d19135386699e2ad58517953b34af",
+                "sha256:b9c40e9750f3d77e6e4d441d8b0266cf555e7cdabdcff33c4fd06366ca761ef8",
+                "sha256:ec9ef8f4a9bc6f71eec99e1806bfa2de401650d996c59330782b89a5555c1497"
+            ],
+            "version": "==4.3.4"
+        },
+        "lazy-object-proxy": {
+            "hashes": [
+                "sha256:0ce34342b419bd8f018e6666bfef729aec3edf62345a53b537a4dcc115746a33",
+                "sha256:1b668120716eb7ee21d8a38815e5eb3bb8211117d9a90b0f8e21722c0758cc39",
+                "sha256:209615b0fe4624d79e50220ce3310ca1a9445fd8e6d3572a896e7f9146bbf019",
+                "sha256:27bf62cb2b1a2068d443ff7097ee33393f8483b570b475db8ebf7e1cba64f088",
+                "sha256:27ea6fd1c02dcc78172a82fc37fcc0992a94e4cecf53cb6d73f11749825bd98b",
+                "sha256:2c1b21b44ac9beb0fc848d3993924147ba45c4ebc24be19825e57aabbe74a99e",
+                "sha256:2df72ab12046a3496a92476020a1a0abf78b2a7db9ff4dc2036b8dd980203ae6",
+                "sha256:320ffd3de9699d3892048baee45ebfbbf9388a7d65d832d7e580243ade426d2b",
+                "sha256:50e3b9a464d5d08cc5227413db0d1c4707b6172e4d4d915c1c70e4de0bbff1f5",
+                "sha256:5276db7ff62bb7b52f77f1f51ed58850e315154249aceb42e7f4c611f0f847ff",
+                "sha256:61a6cf00dcb1a7f0c773ed4acc509cb636af2d6337a08f362413c76b2b47a8dd",
+                "sha256:6ae6c4cb59f199d8827c5a07546b2ab7e85d262acaccaacd49b62f53f7c456f7",
+                "sha256:7661d401d60d8bf15bb5da39e4dd72f5d764c5aff5a86ef52a042506e3e970ff",
+                "sha256:7bd527f36a605c914efca5d3d014170b2cb184723e423d26b1fb2fd9108e264d",
+                "sha256:7cb54db3535c8686ea12e9535eb087d32421184eacc6939ef15ef50f83a5e7e2",
+                "sha256:7f3a2d740291f7f2c111d86a1c4851b70fb000a6c8883a59660d95ad57b9df35",
+                "sha256:81304b7d8e9c824d058087dcb89144842c8e0dea6d281c031f59f0acf66963d4",
+                "sha256:933947e8b4fbe617a51528b09851685138b49d511af0b6c0da2539115d6d4514",
+                "sha256:94223d7f060301b3a8c09c9b3bc3294b56b2188e7d8179c762a1cda72c979252",
+                "sha256:ab3ca49afcb47058393b0122428358d2fbe0408cf99f1b58b295cfeb4ed39109",
+                "sha256:bd6292f565ca46dee4e737ebcc20742e3b5be2b01556dafe169f6c65d088875f",
+                "sha256:cb924aa3e4a3fb644d0c463cad5bc2572649a6a3f68a7f8e4fbe44aaa6d77e4c",
+                "sha256:d0fc7a286feac9077ec52a927fc9fe8fe2fabab95426722be4c953c9a8bede92",
+                "sha256:ddc34786490a6e4ec0a855d401034cbd1242ef186c20d79d2166d6a4bd449577",
+                "sha256:e34b155e36fa9da7e1b7c738ed7767fc9491a62ec6af70fe9da4a057759edc2d",
+                "sha256:e5b9e8f6bda48460b7b143c3821b21b452cb3a835e6bbd5dd33aa0c8d3f5137d",
+                "sha256:e81ebf6c5ee9684be8f2c87563880f93eedd56dd2b6146d8a725b50b7e5adb0f",
+                "sha256:eb91be369f945f10d3a49f5f9be8b3d0b93a4c2be8f8a5b83b0571b8123e0a7a",
+                "sha256:f460d1ceb0e4a5dcb2a652db0904224f367c9b3c1470d5a7683c0480e582468b"
+            ],
+            "version": "==1.3.1"
+        },
+        "mccabe": {
+            "hashes": [
+                "sha256:ab8a6258860da4b6677da4bd2fe5dc2c659cff31b3ee4f7f5d64e79735b80d42",
+                "sha256:dd8d182285a0fe56bace7f45b5e7d1a6ebcbf524e8f3bd87eb0f125271b8831f"
+            ],
+            "version": "==0.6.1"
+        },
+        "pylint": {
+            "hashes": [
+                "sha256:a48070545c12430cfc4e865bf62f5ad367784765681b3db442d8230f0960aa3c",
+                "sha256:fff220bcb996b4f7e2b0f6812fd81507b72ca4d8c4d05daf2655c333800cb9b3"
+            ],
+            "index": "pypi",
+            "version": "==1.9.2"
+        },
+        "six": {
+            "hashes": [
+                "sha256:70e8a77beed4562e7f14fe23a786b54f6296e34344c23bc42f07b15018ff98e9",
+                "sha256:832dc0e10feb1aa2c68dcc57dbb658f1c7e65b9b61af69048abc87a2db00a0eb"
+            ],
+            "version": "==1.11.0"
+        },
+        "wrapt": {
+            "hashes": [
+                "sha256:d4d560d479f2c21e1b5443bbd15fe7ec4b37fe7e53d335d3b9b0a7b1226fe3c6"
+            ],
+            "version": "==1.10.11"
+        }
+    }
 }
diff --git a/calsocial/__init__.py b/calsocial/__init__.py
index 7122c56..534b778 100644
--- a/calsocial/__init__.py
+++ b/calsocial/__init__.py
@@ -32,8 +32,6 @@ def get_locale():
     Selects the best locale based on values sent by the browser.
     """
 
-    from flask import request
-
     supported_languages = ['en', 'hu']
 
     if 'l' in request.args and request.args['l'].lower() in supported_languages:
@@ -62,7 +60,7 @@ def route(*args, **kwargs):
     ``**kwargs`` will be passed verbatim to `Flask.route()`.
     """
 
-    def decorator(func):
+    def decorator(func):  # pylint: disable=missing-docstring
         setattr(func, 'routing', (args, kwargs))
 
         return func
@@ -176,7 +174,8 @@ class CalendarSocialApp(Flask):
         form = RegistrationForm()
 
         if form.validate_on_submit():
-            # TODO: This might become False later, if we want registrations to be confirmed via E-mail
+            # TODO: This might become False later, if we want registrations to be confirmed via
+            #       e-mail
             user = User(active=True)
 
             form.populate_obj(user)
diff --git a/calsocial/calendar_system/gregorian.py b/calsocial/calendar_system/gregorian.py
index 0705269..cb15dc2 100644
--- a/calsocial/calendar_system/gregorian.py
+++ b/calsocial/calendar_system/gregorian.py
@@ -30,10 +30,10 @@ def to_timestamp(func):
     """
 
     @wraps(func)
-    def decorator(*args, **kwargs):
+    def _decorator(*args, **kwargs):
         return func(*args, **kwargs).timestamp()
 
-    return decorator
+    return _decorator
 
 
 class GregorianCalendar(CalendarSystem):
diff --git a/calsocial/forms.py b/calsocial/forms.py
index 2802b77..ea0534e 100644
--- a/calsocial/forms.py
+++ b/calsocial/forms.py
@@ -55,6 +55,8 @@ class TimezoneField(SelectField):
     """
 
     def __init__(self, *args, **kwargs):
+        self.data = None
+
         kwargs.update({
             'choices': [
                 (pytz.timezone(tz), tz.replace('_', ' '))
diff --git a/calsocial/models.py b/calsocial/models.py
index a512dfe..8fb8db1 100644
--- a/calsocial/models.py
+++ b/calsocial/models.py
@@ -74,6 +74,7 @@ class User(db.Model, UserMixin):
     """
 
     __tablename__ = 'users'
+    # pylint: disable=invalid-name
     id = db.Column(db.Integer(), primary_key=True)
 
     #: The username of the user.  This is also the display name and thus is immutable
@@ -132,11 +133,12 @@ class User(db.Model, UserMixin):
         return f'<User {self.id}({self.username})>'
 
 
-class Role(db.Model, RoleMixin):
+class Role(db.Model, RoleMixin):  # pylint: disable=too-few-public-methods
     """Database model for roles
     """
 
     __tablename__ = 'roles'
+    # pylint: disable=invalid-name
     id = db.Column(db.Integer(), primary_key=True)
 
     #: The name of the role
@@ -175,6 +177,7 @@ class Event(db.Model):
     """
 
     __tablename__ = 'events'
+    # pylint: disable=invalid-name
     id = db.Column(db.Integer(), primary_key=True)
 
     #: The ID of the user who created the event