diff --git a/README.md b/README.md
index b7b6237..3ba5589 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,10 @@ Implements the Microsoft Office365 Graph API for the follow
 * Place
   - List Places
   - Get Place
+* Teams
+  - List channel messages
+  - Get channel message
+  - Send channel message
 
 
 ## Installation
diff --git a/spec/chat_messages/channel_messages_spec.cr b/spec/chat_messages/channel_messages_spec.cr
new file mode 100644
index 0000000..b71fa64
--- /dev/null
+++ b/spec/chat_messages/channel_messages_spec.cr
@@ -0,0 +1,45 @@
+require "../spec_helper"
+
+describe Office365::Places do
+  describe "list_messages" do
+    it "list_messages should return the list of messages in channel" do
+      SpecHelper.mock_client_auth
+      SpecHelper.mock_list_channel_msgs
+
+      team_id = "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b"
+      channel_id = "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+
+      client = Office365::Client.new(**SpecHelper.mock_credentials)
+
+      messages = client.list_channel_messages(team_id: team_id, channel_id: channel_id, top: 3)
+      messages.count.should eq(3)
+      messages.next_link.should_not be_nil
+      messages.value.size.should eq(3)
+    end
+
+    it "should get message in channel" do
+      SpecHelper.mock_client_auth
+      SpecHelper.mock_get_channel_msg
+
+      team_id = "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b"
+      channel_id = "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+      msg_id = "1614618259349"
+      client = Office365::Client.new(**SpecHelper.mock_credentials)
+
+      message = client.get_channel_message(team_id: team_id, channel_id: channel_id, message_id: msg_id)
+      message.id.should eq("1612289992105")
+    end
+
+    it "should send message in channel" do
+      SpecHelper.mock_client_auth
+      SpecHelper.mock_channel_send_msg
+
+      team_id = "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b"
+      channel_id = "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+      client = Office365::Client.new(**SpecHelper.mock_credentials)
+
+      resp = client.send_channel_message(team_id, channel_id, "Hello World")
+      resp.status_code.should eq(201)
+    end
+  end
+end
diff --git a/spec/chat_messages/messages.json b/spec/chat_messages/messages.json
new file mode 100644
index 0000000..e58351d
--- /dev/null
+++ b/spec/chat_messages/messages.json
@@ -0,0 +1,144 @@
+{
+    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#teams('fbe2bf47-16c8-47cf-b4a5-4b9b187c508b')/channels('19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2')/messages",
+    "@odata.count": 3,
+    "@odata.nextLink": "https://graph.microsoft.com/v1.0/teams/fbe2bf47-16c8-47cf-b4a5-4b9b187c508b/channels/19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2/messages?$skiptoken=...",
+    "value": [
+      {
+        "id": "1616965872395",
+        "replyToId": null,
+        "etag": "1616965872395",
+        "messageType": "message",
+        "createdDateTime": "2021-03-28T21:11:12.395Z",
+        "lastModifiedDateTime": "2021-03-28T21:11:12.395Z",
+        "lastEditedDateTime": null,
+        "deletedDateTime": null,
+        "subject": null,
+        "summary": null,
+        "chatId": null,
+        "importance": "normal",
+        "locale": "en-us",
+        "webUrl": "https://teams.microsoft.com/l/message/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/1616965872395?groupId=fbe2bf47-16c8-47cf-b4a5-4b9b187c508b&tenantId=2432b57b-0abd-43db-aa7b-16eadd115d34&createdTime=1616965872395&parentMessageId=1616965872395",
+        "policyViolation": null,
+        "eventDetail": null,
+        "from": {
+          "application": null,
+          "device": null,
+          "user": {
+            "id": "8ea0e38b-efb3-4757-924a-5f94061cf8c2",
+            "displayName": "Robin Kline",
+            "userIdentityType": "aadUser"
+          }
+        },
+        "body": {
+          "contentType": "html",
+          "content": "Hello World <at id=\"0\">Jane Smith</at>"
+        },
+        "channelIdentity": {
+          "teamId": "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b",
+          "channelId": "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+        },
+        "attachments": [],
+        "mentions": [
+          {
+            "id": 0,
+            "mentionText": "Jane Smith",
+            "mentioned": {
+              "application": null,
+              "device": null,
+              "conversation": null,
+              "user": {
+                "id": "ef1c916a-3135-4417-ba27-8eb7bd084193",
+                "displayName": "Jane Smith",
+                "userIdentityType": "aadUser"
+              }
+            }
+          }
+        ],
+        "reactions": [],
+        "messageHistory": []
+      },
+      {
+        "id": "1616963377068",
+        "replyToId": null,
+        "etag": "1616963377068",
+        "messageType": "message",
+        "createdDateTime": "2021-03-28T20:29:37.068Z",
+        "lastModifiedDateTime": "2021-03-28T20:29:37.068Z",
+        "lastEditedDateTime": null,
+        "deletedDateTime": null,
+        "subject": "",
+        "summary": null,
+        "chatId": null,
+        "importance": "normal",
+        "locale": "en-us",
+        "webUrl": "https://teams.microsoft.com/l/message/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/1616963377068?groupId=fbe2bf47-16c8-47cf-b4a5-4b9b187c508b&tenantId=2432b57b-0abd-43db-aa7b-16eadd115d34&createdTime=1616963377068&parentMessageId=1616963377068",
+        "policyViolation": null,
+        "eventDetail": null,
+        "from": {
+          "application": null,
+          "device": null,
+          "user": {
+            "id": "8ea0e38b-efb3-4757-924a-5f94061cf8c2",
+            "displayName": "Robin Kline",
+            "userIdentityType": "aadUser"
+          }
+        },
+        "body": {
+          "contentType": "html",
+          "content": "<div><span><img height=\"145\" src=\"https://graph.microsoft.com/v1.0/teams/...\" width=\"131\"></span></div>"
+        },
+        "channelIdentity": {
+          "teamId": "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b",
+          "channelId": "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+        },
+        "attachments": [],
+        "mentions": [],
+        "reactions": [],
+        "messageHistory": []
+      },
+      {
+        "id": "1616883610266",
+        "replyToId": null,
+        "etag": "1616883610266",
+        "messageType": "unknownFutureValue",
+        "createdDateTime": "2021-03-28T03:50:10.266Z",
+        "lastModifiedDateTime": "2021-03-28T03:50:10.266Z",
+        "lastEditedDateTime": null,
+        "deletedDateTime": null,
+        "subject": null,
+        "summary": null,
+        "chatId": null,
+        "importance": "normal",
+        "locale": "en-us",
+        "webUrl": "https://teams.microsoft.com/l/message/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/1616883610266?groupId=fbe2bf47-16c8-47cf-b4a5-4b9b187c508b&tenantId=2432b57b-0abd-43db-aa7b-16eadd115d34&createdTime=1616883610266&parentMessageId=1616883610266",
+        "policyViolation": null,
+        "from": null,
+        "body": {
+          "contentType": "html",
+          "content": "<systemEventMessage/>"
+        },
+        "channelIdentity": {
+          "teamId": "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b",
+          "channelId": "19:4a95f7d8db4c4e7fae857bcebe0623e6@thread.tacv2"
+        },
+        "attachments": [],
+        "mentions": [],
+        "reactions": [],
+        "messageHistory": [],
+        "eventDetail": {
+          "@odata.type": "#microsoft.graph.teamDescriptionUpdatedEventMessageDetail",
+          "teamId": "fbe2bf47-16c8-47cf-b4a5-4b9b187c508b",
+          "teamDescription": "Team for Microsoft Teams members",
+          "initiator": {
+            "application": null,
+            "device": null,
+            "user": {
+              "id": "1fb8890f-423e-4154-8fbf-db6809bc8756",
+              "displayName": null,
+              "userIdentityType": "aadUser"
+            }
+          }
+        }
+      }
+    ]
+  }
\ No newline at end of file
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index 7e11af1..9c7805b 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -648,6 +648,71 @@ module SpecHelper
       ],
     }
   end
+
+  def mock_list_channel_msgs
+    WebMock.stub(:get, "https://graph.microsoft.com/v1.0/teams/fbe2bf47-16c8-47cf-b4a5-4b9b187c508b/channels/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/messages?%24top=3")
+      .to_return(body: mock_list_channel_messages)
+  end
+
+  def mock_list_channel_messages
+    File.read("spec/chat_messages/messages.json")
+  end
+
+  def mock_get_channel_msg
+    WebMock.stub(:get, "https://graph.microsoft.com/v1.0/teams/fbe2bf47-16c8-47cf-b4a5-4b9b187c508b/channels/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/messages/1614618259349")
+      .to_return(body: mock_get_channel_message)
+  end
+
+  def mock_get_channel_message
+    %(
+{
+    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#chats('19%3A8ea0e38b-efb3-4757-924a-5f94061cf8c2_97f62344-57dc-409c-88ad-c4af14158ff5%40unq.gbl.spaces')/messages/$entity",
+    "id": "1612289992105",
+    "replyToId": null,
+    "etag": "1612289992105",
+    "messageType": "message",
+    "createdDateTime": "2021-02-02T18:19:52.105Z",
+    "lastModifiedDateTime": "2021-02-02T18:19:52.105Z",
+    "lastEditedDateTime": null,
+    "deletedDateTime": null,
+    "subject": null,
+    "summary": null,
+    "chatId": "19:8ea0e38b-efb3-4757-924a-5f94061cf8c2_97f62344-57dc-409c-88ad-c4af14158ff5@unq.gbl.spaces",
+    "importance": "normal",
+    "locale": "en-us",
+    "webUrl": null,
+    "channelIdentity": null,
+    "policyViolation": null,
+    "eventDetail": null,
+    "from": {
+        "application": null,
+        "device": null,
+        "conversation": null,
+        "user": {
+            "@odata.type": "#microsoft.graph.teamworkUserIdentity",
+            "id": "8ea0e38b-efb3-4757-924a-5f94061cf8c2",
+            "displayName": "Robin Kline",
+            "userIdentityType": "aadUser",
+            "tenantId": "e61ef81e-8bd8-476a-92e8-4a62f8426fca"
+        }
+    },
+    "body": {
+        "contentType": "text",
+        "content": "test"
+    },
+    "attachments": [],
+    "mentions": [],
+    "reactions": [],
+    "messageHistory": []
+}
+    )
+  end
+
+  def mock_channel_send_msg
+    WebMock.stub(:post, "https://graph.microsoft.com/v1.0/teams/fbe2bf47-16c8-47cf-b4a5-4b9b187c508b/channels/19%3A4a95f7d8db4c4e7fae857bcebe0623e6%40thread.tacv2/messages")
+      .with(body: "{\"body\":{\"content\":\"Hello World\",\"contentType\":\"TEXT\"}}", headers: {"Authorization" => "Bearer access_token", "Content-Type" => "application/json", "Prefer" => "IdType=\"ImmutableId\""})
+      .to_return(status: 201, body: "")
+  end
 end
 
 Spec.before_each do
diff --git a/src/attachments.cr b/src/attachments.cr
index 96bb499..b5db9ee 100644
--- a/src/attachments.cr
+++ b/src/attachments.cr
@@ -29,7 +29,7 @@ module Office365::Attachments
     name : String,
     content_bytes : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     attachment = Attachment.new(name, content_bytes)
     endpoint = event_attachment_path(mailbox, event_id, calendar_group_id, calendar_id)
@@ -57,7 +57,7 @@ module Office365::Attachments
     mailbox : String,
     event_id : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = "#{event_attachment_path(mailbox, event_id, calendar_group_id, calendar_id)}/#{id}"
     graph_http_request(request_method: "GET", path: endpoint)
@@ -83,7 +83,7 @@ module Office365::Attachments
     mailbox : String,
     event_id : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = "#{event_attachment_path(mailbox, event_id, calendar_group_id, calendar_id)}/#{id}"
 
@@ -109,7 +109,7 @@ module Office365::Attachments
     mailbox : String,
     event_id : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = ""
 
diff --git a/src/channel_messages.cr b/src/channel_messages.cr
new file mode 100644
index 0000000..a6303e4
--- /dev/null
+++ b/src/channel_messages.cr
@@ -0,0 +1,58 @@
+module Office365::ChannelMessages
+  def list_channel_messages_request(team_id : String, channel_id : String, filter : String? = nil, match : String? = nil, top : Int32? = nil, skip : Int32? = nil, count : Bool? = nil)
+    query_params = URI::Params.new
+
+    if top
+      query_params["$top"] = top.to_s
+    end
+
+    if count
+      query_params["$count"] = count.to_s
+    end
+
+    if filter
+      query_params["$filter"] = filter
+    end
+
+    if match
+      query_params["$select"] = match
+    end
+
+    if skip
+      query_params["$skip"] = skip.to_s
+    end
+
+    graph_http_request(request_method: "GET", path: "/v1.0/teams/#{team_id}/channels/#{channel_id}/messages", query: query_params)
+  end
+
+  def list_channel_messages(*args, **opts)
+    request = list_channel_messages_request(*args, **opts)
+    response = graph_request(request)
+
+    list_channel_messages(response)
+  end
+
+  def list_channel_messages(response : HTTP::Client::Response)
+    ChatMessageList.from_json(response.body)
+  end
+
+  def get_channel_message(team_id : String, channel_id : String, message_id : String)
+    request = graph_http_request(request_method: "GET", path: "/v1.0/teams/#{team_id}/channels/#{channel_id}/messages/#{message_id}")
+    response = graph_request(request)
+    ChatMessage.from_json(response.body)
+  end
+
+  def send_channel_message(team_id : String, channel_id : String, message : String | IO)
+    body = message.is_a?(IO) ? message.gets_to_end : message
+    chat = ChatMessage.new(body: body)
+    request = graph_http_request(request_method: "POST", path: "/v1.0/teams/#{team_id}/channels/#{channel_id}/messages", data: chat.to_json)
+    graph_request(request)
+  end
+
+  def send_channel_message(team_id : String, channel_id : String, message : String | IO, content_type : String)
+    body = message.is_a?(IO) ? message.gets_to_end : message
+    chat = ChatMessage.new(content: body, content_type: content_type)
+    request = graph_http_request(request_method: "POST", path: "/v1.0/teams/#{team_id}/channels/#{channel_id}/messages", data: chat.to_json)
+    graph_request(request)
+  end
+end
diff --git a/src/client.cr b/src/client.cr
index dbc3a23..919004a 100644
--- a/src/client.cr
+++ b/src/client.cr
@@ -9,6 +9,7 @@ require "./subscriptions"
 require "./odata"
 require "./password_credentials"
 require "./places"
+require "./channel_messages"
 
 module Office365
   USERS_BASE       = "/v1.0/users"
@@ -27,6 +28,7 @@ module Office365
     include Office365::OData
     include Office365::PasswordCredentials
     include Office365::Places
+    include Office365::ChannelMessages
 
     LOGIN_URI     = URI.parse("https://login.microsoftonline.com")
     GRAPH_URI     = URI.parse("https://graph.microsoft.com/")
@@ -114,7 +116,7 @@ module Office365
       path : String,
       data : String? = nil,
       query : URI::Params? = nil,
-      headers : HTTP::Headers = default_headers
+      headers : HTTP::Headers = default_headers,
     ) : HTTP::Request
       uri = if query && !query.empty?
               "#{URI.encode_path(URI.decode(path))}?#{query}"
diff --git a/src/events.cr b/src/events.cr
index 932a270..b554561 100644
--- a/src/events.cr
+++ b/src/events.cr
@@ -7,7 +7,7 @@ module Office365::Events
     period_end : Time? = nil,
     ical_uid : String? = nil,
     top : Int32? = 10000,
-    filter : String? = nil
+    filter : String? = nil,
   )
     path, params = calendar_view_path(mailbox, calendar_group_id, calendar_id, period_start, period_end, ical_uid, top, filter)
 
@@ -31,7 +31,7 @@ module Office365::Events
     ends_at : Time?,
     calendar_group_id : String? = nil,
     calendar_id : String? = nil,
-    **opts
+    **opts,
   )
     event = Event.new(**opts.merge(starts_at: starts_at, ends_at: ends_at))
     endpoint = calendar_event_path(mailbox, calendar_group_id, calendar_id)
@@ -54,7 +54,7 @@ module Office365::Events
     id : String,
     mailbox : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{id}"
     graph_http_request(request_method: "GET", path: endpoint)
@@ -75,7 +75,7 @@ module Office365::Events
     event : Event,
     mailbox : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{event.id}"
 
@@ -97,7 +97,7 @@ module Office365::Events
     id : String,
     mailbox : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{id}"
 
@@ -121,7 +121,7 @@ module Office365::Events
     calendar_group_id : String? = nil,
     calendar_id : String? = nil,
     notify : Bool = true,
-    comment : String? = nil
+    comment : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{id}/decline"
 
@@ -147,7 +147,7 @@ module Office365::Events
     mailbox : String,
     calendar_group_id : String? = nil,
     calendar_id : String? = nil,
-    comment : String? = nil
+    comment : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{id}/cancel"
 
@@ -175,7 +175,7 @@ module Office365::Events
     calendar_group_id : String? = nil,
     calendar_id : String? = nil,
     notify : Bool = true,
-    comment : String? = nil
+    comment : String? = nil,
   )
     endpoint = "#{calendar_event_path(mailbox, calendar_group_id, calendar_id)}/#{id}/accept"
 
@@ -199,7 +199,7 @@ module Office365::Events
   private def calendar_event_path(
     mailbox : String,
     calendar_group_id : String? = nil,
-    calendar_id : String? = nil
+    calendar_id : String? = nil,
   )
     # we assume we are actually after a mailbox as calendar_ids are not emails
     if calendar_id.try &.includes?('@')
@@ -229,7 +229,7 @@ module Office365::Events
     period_end : Time? = nil,
     ical_uid : String? = nil,
     top : Int32? = 10000,
-    filter : String? = nil
+    filter : String? = nil,
   )
     end_period = period_end || period_start + 6.months
 
diff --git a/src/models/channel_identity.cr b/src/models/channel_identity.cr
new file mode 100644
index 0000000..8ff9f50
--- /dev/null
+++ b/src/models/channel_identity.cr
@@ -0,0 +1,11 @@
+module Office365
+  class ChannelIdentity
+    include JSON::Serializable
+
+    @[JSON::Field(key: "channelId")]
+    property channel_id : String
+
+    @[JSON::Field(key: "teamId")]
+    property team_id : String
+  end
+end
diff --git a/src/models/chat_message.cr b/src/models/chat_message.cr
new file mode 100644
index 0000000..1d894d4
--- /dev/null
+++ b/src/models/chat_message.cr
@@ -0,0 +1,191 @@
+module Office365
+  enum ChatMessageType
+    Message
+    ChatEvent
+    Typing
+    UnknownFutureValue
+    SystemEventMessage
+
+    def to_json(json : JSON::Builder)
+      val = to_s
+      val = val[0].downcase + val[1..]
+      json.string(val)
+    end
+  end
+
+  enum ChatMessageActions
+    ReactionAdded
+    ReactionRemoved
+    ActionUndefined
+    UnknownFutureValue
+
+    def to_json(json : JSON::Builder)
+      val = to_s
+      val = val[0].downcase + val[1..]
+      json.string(val)
+    end
+  end
+
+  enum ChatMessagePolicyViolationDlpActionType
+    None
+    NotifySender
+    BlockAccess
+    BlockAccessExternal
+  end
+
+  class ChatMessageMention
+    include JSON::Serializable
+
+    property id : Int32?
+    property mentioned : ChatMessageMentionedIdentitySet?
+
+    @[JSON::Field(key: "mentionText")]
+    property mention_text : String?
+  end
+
+  class ChatMessageReaction
+    include JSON::Serializable
+
+    @[JSON::Field(key: "createdDateTime")]
+    property created_date_time : String?
+
+    @[JSON::Field(key: "displayName")]
+    property display_name : String?
+
+    @[JSON::Field(key: "reactionContentUrl")]
+    property reaction_content_url : String?
+
+    @[JSON::Field(key: "reactionType")]
+    property reaction_type : String?
+
+    property user : ChatMessageReactionIdentitySet?
+  end
+
+  class ChatMessageHistoryItem
+    include JSON::Serializable
+
+    property actions : ChatMessageActions
+
+    @[JSON::Field(key: "modifiedDateTime")]
+    property modified_date_time : Time?
+
+    property reaction : ChatMessageReaction?
+  end
+
+  class ChatMessagePolicyTip
+    include JSON::Serializable
+
+    @[JSON::Field(key: "complianceUrl")]
+    property compliance_url : String?
+
+    @[JSON::Field(key: "generalText")]
+    property general_text : String?
+
+    @[JSON::Field(key: "matchedConditionDescriptions")]
+    property matched_condition_descriptions : Array(String)?
+  end
+
+  class ChatMessagePolicyViolation
+    include JSON::Serializable
+
+    @[JSON::Field(key: "dlpAction")]
+    property dlp_action : ChatMessagePolicyViolationDlpActionType?
+
+    @[JSON::Field(key: "justificationText")]
+    property justification_text : String?
+
+    @[JSON::Field(key: "policyTip")]
+    property policy_tip : ChatMessagePolicyTip?
+
+    @[JSON::Field(key: "userAction")]
+    property user_action : ChatMessagePolicyViolationDlpActionType?
+
+    @[JSON::Field(key: "verdictDetails")]
+    property verdict_details : ChatMessagePolicyViolationDlpActionType?
+  end
+
+  class ChatMessage
+    include JSON::Serializable
+    include JSON::Serializable::Unmapped
+
+    property attachments : Array(ChatMessageAttachment)?
+    property body : ItemBody
+
+    @[JSON::Field(key: "chatId")]
+    property chat_id : String?
+
+    @[JSON::Field(key: "channelIdentity")]
+    property channel_identity : ChannelIdentity?
+
+    @[JSON::Field(key: "createdDateTime")]
+    property created_date_time : Time?
+
+    @[JSON::Field(key: "deletedDateTime")]
+    property deleted_date_time : Time?
+
+    property etag : String?
+
+    # @[JSON::Field(key: "eventDetail")]
+    # property event_detail : EventMessageDetail?
+
+    property from : ChatMessageFromIdentitySet?
+    property id : String?
+    property importance : String?
+
+    @[JSON::Field(key: "lastModifiedDateTime")]
+    property last_modified_date_time : Time?
+
+    @[JSON::Field(key: "lastEditedDateTime")]
+    property last_edited_date_time : Time?
+
+    property locale : String?
+    property mentions : Array(ChatMessageMention)?
+
+    @[JSON::Field(key: "messageHistory")]
+    property message_history : Array(ChatMessageHistoryItem)?
+
+    @[JSON::Field(key: "messageType")]
+    property message_type : ChatMessageType?
+
+    @[JSON::Field(key: "policyViolation")]
+    property policy_violation : ChatMessagePolicyViolation?
+
+    property reactions : Array(ChatMessageReaction)?
+
+    @[JSON::Field(key: "replyToId")]
+    property reply_to_id : String?
+
+    property subject : String?
+    property summary : String?
+
+    @[JSON::Field(key: "webUrl")]
+    property web_url : String?
+
+    def initialize(@body, @attachments = nil, @chat_id = nil, @channel_identity = nil, @created_date_time = nil, @deleted_date_time = nil, @etag = nil, @from = nil, @id = nil, @importance = nil, @last_modified_date_time = nil,
+                   @last_edited_date_time = nil, @locale = nil, @mentions = nil, @message_history = nil, @message_type = nil, @policy_violation = nil, @reactions = nil, @subject = nil, @summary = nil, @web_url = nil)
+    end
+
+    def self.new(content : String, content_type : String)
+      new(body: ItemBody.new(content: content, content_type: content_type))
+    end
+
+    def self.new(body : String)
+      new(content: body, content_type: "TEXT")
+    end
+  end
+
+  class ChatMessageList
+    include JSON::Serializable
+
+    @[JSON::Field(key: "@odata.context")]
+    property context : String
+
+    @[JSON::Field(key: "@odata.count")]
+    property count : Int32
+
+    @[JSON::Field(key: "@odata.nextLink")]
+    property next_link : String?
+
+    property value : Array(ChatMessage)
+  end
+end
diff --git a/src/models/chat_msg_attachment.cr b/src/models/chat_msg_attachment.cr
new file mode 100644
index 0000000..c8aea22
--- /dev/null
+++ b/src/models/chat_msg_attachment.cr
@@ -0,0 +1,21 @@
+module Office365
+  class ChatMessageAttachment
+    include JSON::Serializable
+
+    property id : String
+    property name : String?
+    property content : String?
+
+    @[JSON::Field(key: "contentType")]
+    property content_type : String?
+
+    @[JSON::Field(key: "contentUrl")]
+    property content_url : String?
+
+    @[JSON::Field(key: "teamsAppId")]
+    property teams_app_id : String?
+
+    @[JSON::Field(key: "thumbnailUrl")]
+    property thumbnail_url : String?
+  end
+end
diff --git a/src/models/event.cr b/src/models/event.cr
index 2bd69a2..0e9d7c4 100644
--- a/src/models/event.cr
+++ b/src/models/event.cr
@@ -129,7 +129,7 @@ module Office365
       @id = nil,
       @series_master_id = nil,
       @online_meeting_provider = nil,
-      @hide_attendees = false
+      @hide_attendees = false,
     )
       @body = ItemBody.new(description)
       @is_online_meeting = @online_meeting_provider ? true : nil
diff --git a/src/models/event_msg_detail.cr b/src/models/event_msg_detail.cr
new file mode 100644
index 0000000..33f9f6a
--- /dev/null
+++ b/src/models/event_msg_detail.cr
@@ -0,0 +1,38 @@
+module Office365
+  abstract class EventMessageDetail
+    include JSON::Serializable
+
+    @[JSON::Field(key: "@odata.type")]
+    property type : String
+
+    use_json_discriminator "@odata.type", {
+      "#microsoft.graph.callEndedEventMessageDetail"    => CallEndedEvent,
+      "#microsoft.graph.channelAddedEventMessageDetail" => ChannelAddedEvent,
+    }
+  end
+
+  class CallEndedEvent < EventMessageDetail
+    include JSON::Serializable
+    include JSON::Serializable::Unmapped
+
+    @[JSON::Field(key: "callDuration")]
+    property call_duration : String?
+
+    @[JSON::Field(key: "callEventType")]
+    property call_event_type : String?
+
+    @[JSON::Field(key: "callId")]
+    property call_id : String?
+  end
+
+  class ChannelAddedEvent < EventMessageDetail
+    include JSON::Serializable
+    include JSON::Serializable::Unmapped
+
+    @[JSON::Field(key: "channelDisplayName")]
+    property channel_display_name : String?
+
+    @[JSON::Field(key: "channelId")]
+    property channel_id : String?
+  end
+end
diff --git a/src/models/identity.cr b/src/models/identity.cr
new file mode 100644
index 0000000..ba376ed
--- /dev/null
+++ b/src/models/identity.cr
@@ -0,0 +1,67 @@
+module Office365
+  class Identity
+    include JSON::Serializable
+
+    property id : String
+
+    @[JSON::Field(key: "displayName")]
+    property display_name : String?
+
+    @[JSON::Field(key: "tenantId")]
+    property tenant_id : String?
+
+    property thumbnails : ThumbnailSet?
+  end
+
+  class TeamworkUserIdentity
+    include JSON::Serializable
+
+    property id : String
+
+    @[JSON::Field(key: "displayName")]
+    property display_name : String?
+
+    @[JSON::Field(key: "tenantId")]
+    property tenant_id : String?
+
+    @[JSON::Field(key: "userIdentityType")]
+    property user_identity_type : String?
+  end
+
+  class ChatMessageFromIdentitySet
+    include JSON::Serializable
+
+    property application : Identity?
+    property device : Identity?
+    property user : TeamworkUserIdentity?
+  end
+
+  class TeamworkConversationIdentity
+    include JSON::Serializable
+
+    property id : String
+
+    @[JSON::Field(key: "displayName")]
+    property display_name : String?
+
+    @[JSON::Field(key: "conversationIdentityType")]
+    property conversation_identity_type : String?
+  end
+
+  class ChatMessageMentionedIdentitySet
+    include JSON::Serializable
+
+    property application : Identity?
+    property conversation : TeamworkConversationIdentity?
+    property device : Identity?
+    property user : Identity?
+  end
+
+  class ChatMessageReactionIdentitySet
+    include JSON::Serializable
+
+    property application : Identity?
+    property device : Identity?
+    property user : Identity?
+  end
+end
diff --git a/src/models/message.cr b/src/models/message.cr
index b780812..6014b24 100644
--- a/src/models/message.cr
+++ b/src/models/message.cr
@@ -55,7 +55,7 @@ module Office365
       cc : Array(String) | Array(EmailAddress) | Nil = nil,
       bcc : Array(String) | Array(EmailAddress) | Nil = nil,
       @body_preview = nil,
-      @attachments = nil
+      @attachments = nil,
     )
       @body = Body.new(content, content_type)
       @to = to_recipient(to)
diff --git a/src/models/thumbnail.cr b/src/models/thumbnail.cr
new file mode 100644
index 0000000..5ac75e8
--- /dev/null
+++ b/src/models/thumbnail.cr
@@ -0,0 +1,23 @@
+module Office365
+  class Thumbnail
+    include JSON::Serializable
+
+    property height : Int32?
+    property width : Int32?
+    property content : String?
+    property url : String?
+
+    @[JSON::Field(key: "sourceItemId")]
+    property source_item_id : String?
+  end
+
+  class ThumbnailSet
+    include JSON::Serializable
+
+    property id : String?
+    property large : Thumbnail?
+    property medium : Thumbnail?
+    property small : Thumbnail?
+    property source : Thumbnail?
+  end
+end
diff --git a/src/subscriptions.cr b/src/subscriptions.cr
index b10c974..2b6bc44 100644
--- a/src/subscriptions.cr
+++ b/src/subscriptions.cr
@@ -6,7 +6,7 @@ module Office365::Subscriptions
     expiration_date_time : Time,
     client_state : String? = nil,
     lifecycle_notification_url : String? = nil,
-    **opts
+    **opts,
   )
     sub = Subscription.new(resource, change_types, notification_url, expiration_date_time, client_state, lifecycle_notification_url)
     graph_http_request(request_method: "POST", path: "/v1.0/subscriptions", data: sub.to_json)
@@ -25,7 +25,7 @@ module Office365::Subscriptions
   # renew a subscription
   def renew_subscription_request(
     subscription_id : String,
-    expiration_date_time : Time
+    expiration_date_time : Time,
   )
     graph_http_request(
       request_method: "PATCH",