diff --git a/lib/shared/dm-ops/create-thread-spec.js b/lib/shared/dm-ops/create-thread-spec.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/dm-ops/create-thread-spec.js
@@ -0,0 +1,14 @@
+// @flow
+
+import type { DMOperationSpec } from './dm-op-spec.js';
+import type { DMCreateThreadOperation } from '../../types/dm-ops.js';
+
+export const createThreadSpec: DMOperationSpec<DMCreateThreadOperation> =
+  Object.freeze({
+    processDMOperation: async () => {
+      return {
+        rawMessageInfos: [],
+        updateInfos: [],
+      };
+    },
+  });
diff --git a/lib/shared/dm-ops/dm-op-spec.js b/lib/shared/dm-ops/dm-op-spec.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/dm-ops/dm-op-spec.js
@@ -0,0 +1,17 @@
+// @flow
+
+import type { DMOperation, DMOperationResult } from '../../types/dm-ops.js';
+import type { RawMessageInfo } from '../../types/message-types.js';
+
+export type ProcessDMOperationUtilities = {
+  // Needed to fetch sidebar source messages
+  +fetchMessage: (messageID: string) => Promise<?RawMessageInfo>,
+};
+
+export type DMOperationSpec<DMOp: DMOperation> = {
+  +processDMOperation: (
+    dmOp: DMOp,
+    viewerID: string,
+    utilities: ProcessDMOperationUtilities,
+  ) => Promise<DMOperationResult>,
+};
diff --git a/lib/shared/dm-ops/dm-op-specs.js b/lib/shared/dm-ops/dm-op-specs.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/dm-ops/dm-op-specs.js
@@ -0,0 +1,13 @@
+// @flow
+
+import { createThreadSpec } from './create-thread-spec.js';
+import type { DMOperationSpec } from './dm-op-spec.js';
+import { sendTextMessageSpec } from './send-text-message-spec.js';
+import { type DMOperationType, dmOperationTypes } from '../../types/dm-ops.js';
+
+export const dmOpSpecs: {
+  +[DMOperationType]: DMOperationSpec<any>,
+} = Object.freeze({
+  [dmOperationTypes.CREATE_THREAD]: createThreadSpec,
+  [dmOperationTypes.SEND_TEXT_MESSAGE]: sendTextMessageSpec,
+});
diff --git a/lib/shared/dm-ops/send-text-message-spec.js b/lib/shared/dm-ops/send-text-message-spec.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/dm-ops/send-text-message-spec.js
@@ -0,0 +1,14 @@
+// @flow
+
+import type { DMOperationSpec } from './dm-op-spec.js';
+import type { DMSendTextMessageOperation } from '../../types/dm-ops.js';
+
+export const sendTextMessageSpec: DMOperationSpec<DMSendTextMessageOperation> =
+  Object.freeze({
+    processDMOperation: async () => {
+      return {
+        rawMessageInfos: [],
+        updateInfos: [],
+      };
+    },
+  });
diff --git a/lib/types/dm-ops.js b/lib/types/dm-ops.js
new file mode 100644
--- /dev/null
+++ b/lib/types/dm-ops.js
@@ -0,0 +1,63 @@
+// @flow
+
+import type { TInterface } from 'tcomb';
+import t from 'tcomb';
+
+import type { RawMessageInfo } from './message-types.js';
+import { type ThickThreadType, thickThreadTypes } from './thread-types-enum.js';
+import type { ClientUpdateInfo } from './update-types.js';
+import { values } from '../utils/objects.js';
+import { tShape, tString, tUserID } from '../utils/validation-utils.js';
+
+export const dmOperationTypes = Object.freeze({
+  CREATE_THREAD: 'create_thread',
+  SEND_TEXT_MESSAGE: 'send_text_message',
+});
+export type DMOperationType = $Values<typeof dmOperationTypes>;
+
+export type DMCreateThreadOperation = {
+  +type: 'create_thread',
+  +threadID: string,
+  +creatorID: string,
+  +time: number,
+  +threadType: ThickThreadType,
+  +parentThreadID?: ?string,
+  +memberIDs: $ReadOnlyArray<string>,
+  +sourceMessageID?: ?string,
+};
+export const dmCreateThreadOperationValidator: TInterface<DMCreateThreadOperation> =
+  tShape<DMCreateThreadOperation>({
+    type: tString(dmOperationTypes.CREATE_THREAD),
+    threadID: t.String,
+    creatorID: tUserID,
+    time: t.Number,
+    threadType: t.enums.of(values(thickThreadTypes)),
+    parentThreadID: t.maybe(t.String),
+    memberIDs: t.list(tUserID),
+    sourceMessageID: t.maybe(t.String),
+  });
+
+export type DMSendTextMessageOperation = {
+  +type: 'send_text_message',
+  +threadID: string,
+  +creatorID: string,
+  +time: number,
+  +messageID: string,
+  +text: string,
+};
+export const dmSendTextMessageOperationValidator: TInterface<DMSendTextMessageOperation> =
+  tShape<DMSendTextMessageOperation>({
+    type: tString(dmOperationTypes.SEND_TEXT_MESSAGE),
+    threadID: t.String,
+    creatorID: tUserID,
+    time: t.Number,
+    messageID: t.String,
+    text: t.String,
+  });
+
+export type DMOperation = DMCreateThreadOperation | DMSendTextMessageOperation;
+
+export type DMOperationResult = {
+  rawMessageInfos: Array<RawMessageInfo>,
+  updateInfos: Array<ClientUpdateInfo>,
+};