diff --git a/maubot/__init__.py b/maubot/__init__.py
index 9c3cbb8..5dd2035 100644
--- a/maubot/__init__.py
+++ b/maubot/__init__.py
@@ -1,3 +1,4 @@
 from .plugin_base import Plugin
 from .command_spec import CommandSpec, Command, PassiveCommand, Argument
 from .event import FakeEvent as Event
+from .client import MaubotMatrixClient as Client
diff --git a/maubot/client.py b/maubot/client.py
index 539ca54..30cccff 100644
--- a/maubot/client.py
+++ b/maubot/client.py
@@ -13,33 +13,80 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import Dict, Optional
+from typing import Dict, List, Optional, Union, Callable
 from aiohttp import ClientSession
+import asyncio
 import logging
 
 from mautrix import Client as MatrixClient
+from mautrix.client import EventHandler
 from mautrix.types import (UserID, SyncToken, FilterID, ContentURI, StateEvent, Membership,
-                           EventType)
+                           EventType, MessageEvent)
 
+from .command_spec import ParsedCommand
 from .db import DBClient
 
 log = logging.getLogger("maubot.client")
 
 
+class MaubotMatrixClient(MatrixClient):
+    def __init__(self, maubot_client: 'Client', *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._maubot_client = maubot_client
+        self.command_handlers: Dict[str, List[EventHandler]] = {}
+        self.commands: List[ParsedCommand] = []
+
+        self.add_event_handler(self._command_event_handler, EventType.ROOM_MESSAGE)
+
+    async def _command_event_handler(self, evt: MessageEvent) -> None:
+        for command in self.commands:
+            if command.match(evt):
+                await self._trigger_command(command, evt)
+                return
+
+    async def _trigger_command(self, command: ParsedCommand, evt: MessageEvent) -> None:
+        for handler in self.command_handlers.get(command.name, []):
+            await handler(evt)
+
+    def on(self, var: Union[EventHandler, EventType, str]
+           ) -> Union[EventHandler, Callable[[EventHandler], EventHandler]]:
+        if isinstance(var, str):
+            def decorator(func: EventHandler) -> EventHandler:
+                self.add_command_handler(var, func)
+                return func
+
+            return decorator
+        return super().on(var)
+
+    def add_command_handler(self, command: str, handler: EventHandler) -> None:
+        self.command_handlers.setdefault(command, []).append(handler)
+
+    def remove_command_handler(self, command: str, handler: EventHandler) -> None:
+        try:
+            self.command_handlers[command].remove(handler)
+        except (KeyError, ValueError):
+            pass
+
+
 class Client:
     cache: Dict[UserID, 'Client'] = {}
     http_client: ClientSession = None
 
+    db_instance: DBClient
+    client: MaubotMatrixClient
+
     def __init__(self, db_instance: DBClient) -> None:
-        self.db_instance: DBClient = db_instance
+        self.db_instance = db_instance
         self.cache[self.id] = self
-        self.client: MatrixClient = MatrixClient(mxid=self.id,
-                                                 base_url=self.homeserver,
-                                                 token=self.access_token,
-                                                 client_session=self.http_client,
-                                                 log=log.getChild(self.id))
+        self.client = MaubotMatrixClient(maubot_client=self,
+                                         store=self.db_instance,
+                                         mxid=self.id,
+                                         base_url=self.homeserver,
+                                         token=self.access_token,
+                                         client_session=self.http_client,
+                                         log=log.getChild(self.id))
         if self.autojoin:
-            self.client.add_event_handler(self.handle_invite, EventType.ROOM_MEMBER)
+            self.client.add_event_handler(self._handle_invite, EventType.ROOM_MEMBER)
 
     @classmethod
     def get(cls, user_id: UserID) -> Optional['Client']:
@@ -103,9 +150,9 @@ class Client:
         if value == self.db_instance.autojoin:
             return
         if value:
-            self.client.add_event_handler(self.handle_invite, EventType.ROOM_MEMBER)
+            self.client.add_event_handler(self._handle_invite, EventType.ROOM_MEMBER)
         else:
-            self.client.remove_event_handler(self.handle_invite, EventType.ROOM_MEMBER)
+            self.client.remove_event_handler(self._handle_invite, EventType.ROOM_MEMBER)
         self.db_instance.autojoin = value
 
     @property
@@ -126,6 +173,6 @@ class Client:
 
     # endregion
 
-    async def handle_invite(self, evt: StateEvent) -> None:
+    async def _handle_invite(self, evt: StateEvent) -> None:
         if evt.state_key == self.id and evt.content.membership == Membership.INVITE:
             await self.client.join_room_by_id(evt.room_id)
diff --git a/maubot/command_spec.py b/maubot/command_spec.py
index 8ac6e23..8a8dc6a 100644
--- a/maubot/command_spec.py
+++ b/maubot/command_spec.py
@@ -13,10 +13,11 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
-from typing import List, Dict
+from typing import List, Dict, Pattern, Union, Tuple, Optional, Any
 from attr import dataclass
+import re
 
-from mautrix.types import Event
+from mautrix.types import MessageEvent, MatchedCommand, MatchedPassiveCommand
 from mautrix.client.api.types.util import SerializableAttrs
 
 
@@ -39,7 +40,103 @@ class PassiveCommand(SerializableAttrs['PassiveCommand']):
     name: str
     matches: str
     match_against: str
-    match_event: Event = None
+    match_event: MessageEvent = None
+
+
+class ParsedCommand:
+    name: str
+    is_passive: bool
+    arguments: List[str]
+    starts_with: str
+    matches: Pattern
+    match_against: str
+    match_event: MessageEvent
+
+    def __init__(self, command: Union[PassiveCommand, Command]) -> None:
+        if isinstance(command, PassiveCommand):
+            self._init_passive(command)
+        elif isinstance(command, Command):
+            self._init_active(command)
+        else:
+            raise ValueError("Command parameter must be a Command or a PassiveCommand.")
+
+    def _init_passive(self, command: PassiveCommand) -> None:
+        self.name = command.name
+        self.is_passive = True
+        self.match_against = command.match_against
+        self.matches = re.compile(command.matches)
+        self.match_event = command.match_event
+
+    def _init_active(self, command: Command) -> None:
+        self.name = command.syntax
+        self.is_passive = False
+
+        regex_builder = []
+        sw_builder = []
+        argument_encountered = False
+
+        for word in command.syntax.split(" "):
+            arg = command.arguments.get(word, None)
+            if arg is not None and len(word) > 0:
+                argument_encountered = True
+                regex = f"({arg.matches})" if arg.required else f"(?:{arg.matches})?"
+                self.arguments.append(word)
+                regex_builder.append(regex)
+            else:
+                if not argument_encountered:
+                    sw_builder.append(word)
+                regex_builder.append(re.escape(word))
+        self.starts_with = "!" + " ".join(sw_builder)
+        self.matches = re.compile("^!" + " ".join(regex_builder) + "$")
+        self.match_against = "body"
+
+    def match(self, evt: MessageEvent) -> bool:
+        return self._match_passive(evt) if self.is_passive else self._match_active(evt)
+
+    @staticmethod
+    def _parse_key(key: str) -> Tuple[str, Optional[str]]:
+        if '.' not in key:
+            return key, None
+        key, next_key = key.split('.', 1)
+        if len(key) > 0 and key[0] == "[":
+            end_index = next_key.index("]")
+            key = key[1:] + "." + next_key[:end_index]
+            next_key = next_key[end_index + 2:] if len(next_key) > end_index + 1 else None
+        return key, next_key
+
+    @classmethod
+    def _recursive_get(cls, data: Any, key: str) -> Any:
+        if not data:
+            return None
+        key, next_key = cls._parse_key(key)
+        if next_key is not None:
+            return cls._recursive_get(data[key], next_key)
+        return data[key]
+
+    def _match_passive(self, evt: MessageEvent) -> bool:
+        try:
+            match_against = self._recursive_get(evt.content, self.match_against)
+        except KeyError:
+            match_against = None
+        match_against = match_against or evt.content.body
+        matches = [[match.string[match.start():match.end()]] + list(match.groups())
+                   for match in self.matches.finditer(match_against)]
+        if not matches:
+            return False
+        if evt.unsigned.passive_command is None:
+            evt.unsigned.passive_command = {}
+        evt.unsigned.passive_command[self.name] = MatchedPassiveCommand(captured=matches)
+        return True
+
+    def _match_active(self, evt: MessageEvent) -> bool:
+        if not evt.content.body.startswith(self.starts_with):
+            return False
+        match = self.matches.match(evt.content.body)
+        if not match:
+            return False
+        evt.content.command = MatchedCommand(matched=self.name,
+                                             arguments=dict(zip(self.arguments, match.groups())))
+        return True
 
 
 @dataclass
@@ -50,3 +147,6 @@ class CommandSpec(SerializableAttrs['CommandSpec']):
     def __add__(self, other: 'CommandSpec') -> 'CommandSpec':
         return CommandSpec(commands=self.commands + other.commands,
                            passive_commands=self.passive_commands + other.passive_commands)
+
+    def parse(self) -> List[ParsedCommand]:
+        return [ParsedCommand(command) for command in self.commands + self.passive_commands]
diff --git a/maubot/db.py b/maubot/db.py
index 841dbe8..9c4ccc1 100644
--- a/maubot/db.py
+++ b/maubot/db.py
@@ -13,31 +13,39 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
+from typing import Type
 from sqlalchemy import (Column, String, Boolean, ForeignKey, Text, TypeDecorator)
 from sqlalchemy.orm import Query
 from sqlalchemy.ext.declarative import declarative_base
 import json
 
-from mautrix.types import JSON, UserID, FilterID, SyncToken, ContentURI
+from mautrix.types import UserID, FilterID, SyncToken, ContentURI
+from mautrix.client.api.types.util import Serializable
+from mautrix import ClientStore
+
+from .command_spec import CommandSpec
 
 Base: declarative_base = declarative_base()
 
 
-class JSONEncodedDict(TypeDecorator):
-    impl = Text
+def make_serializable_alchemy(serializable_type: Type[Serializable]):
+    class SerializableAlchemy(TypeDecorator):
+        impl = Text
 
-    @property
-    def python_type(self):
-        return dict
+        @property
+        def python_type(self):
+            return serializable_type
 
-    def process_literal_param(self, value, _):
-        return json.dumps(value) if value is not None else None
+        def process_literal_param(self, value: Serializable, _) -> str:
+            return json.dumps(value.serialize()) if value is not None else None
 
-    def process_bind_param(self, value, _):
-        return json.dumps(value) if value is not None else None
+        def process_bind_param(self, value: Serializable, _) -> str:
+            return json.dumps(value.serialize()) if value is not None else None
 
-    def process_result_value(self, value, _):
-        return json.loads(value) if value is not None else None
+        def process_result_value(self, value: str, _) -> serializable_type:
+            return serializable_type.deserialize(json.loads(value)) if value is not None else None
+
+    return SerializableAlchemy
 
 
 class DBPlugin(Base):
@@ -52,7 +60,7 @@ class DBPlugin(Base):
                                   nullable=False)
 
 
-class DBClient(Base):
+class DBClient(ClientStore, Base):
     query: Query
     __tablename__ = "client"
 
@@ -74,10 +82,10 @@ class DBCommandSpec(Base):
     query: Query
     __tablename__ = "command_spec"
 
-    owner: str = Column(String(255),
-                        ForeignKey("plugin.id", onupdate="CASCADE", ondelete="CASCADE"),
-                        primary_key=True)
+    plugin: str = Column(String(255),
+                         ForeignKey("plugin.id", onupdate="CASCADE", ondelete="CASCADE"),
+                         primary_key=True)
     client: UserID = Column(String(255),
                             ForeignKey("client.id", onupdate="CASCADE", ondelete="CASCADE"),
                             primary_key=True)
-    spec: JSON = Column(JSONEncodedDict, nullable=False)
+    spec: CommandSpec = Column(make_serializable_alchemy(CommandSpec), nullable=False)
diff --git a/maubot/plugin_base.py b/maubot/plugin_base.py
index 489352a..0f22c00 100644
--- a/maubot/plugin_base.py
+++ b/maubot/plugin_base.py
@@ -17,13 +17,17 @@ from typing import TYPE_CHECKING
 from abc import ABC
 
 if TYPE_CHECKING:
-    from mautrix import Client as MatrixClient
+    from .client import MaubotMatrixClient
+    from .command_spec import CommandSpec
 
 
 class Plugin(ABC):
-    def __init__(self, client: 'MatrixClient') -> None:
+    def __init__(self, client: 'MaubotMatrixClient') -> None:
         self.client = client
 
+    def set_command_spec(self, spec: 'CommandSpec') -> None:
+        pass
+
     async def start(self) -> None:
         pass
 
diff --git a/requirements.txt b/requirements.txt
index 318c4e2..f8671cd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,3 +4,4 @@ SQLAlchemy
 alembic
 commonmark
 ruamel.yaml
+attrs
diff --git a/setup.py b/setup.py
index ca44f69..aaae281 100644
--- a/setup.py
+++ b/setup.py
@@ -27,6 +27,7 @@ setuptools.setup(
         "alembic>=1.0.0,<2",
         "commonmark>=0.8.1,<1",
         "ruamel.yaml>=0.15.35,<0.16",
+        "attrs>=18.2.0,<19",
     ],
 
     classifiers=[