diff --git a/keyserver/src/creators/message-creator.js b/keyserver/src/creators/message-creator.js
--- a/keyserver/src/creators/message-creator.js
+++ b/keyserver/src/creators/message-creator.js
@@ -4,11 +4,8 @@
 import _pickBy from 'lodash/fp/pickBy.js';
 
 import { permissionLookup } from 'lib/permissions/thread-permissions.js';
-import {
-  generateNotifUserInfoPromise,
-  type Device,
-  type PushUserInfo,
-} from 'lib/push/send-utils.js';
+import { type Device, type PushUserInfo } from 'lib/push/send-utils.js';
+import { generateNotifUserInfoPromise } from 'lib/push/utils.js';
 import {
   rawMessageInfoFromMessageData,
   shimUnsupportedRawMessageInfos,
diff --git a/keyserver/src/push/send.js b/keyserver/src/push/send.js
--- a/keyserver/src/push/send.js
+++ b/keyserver/src/push/send.js
@@ -19,7 +19,8 @@
   createAndroidBadgeOnlyNotification,
 } from 'lib/push/android-notif-creators.js';
 import { apnMaxNotificationPayloadByteSize } from 'lib/push/apns-notif-creators.js';
-import type { Device, PushUserInfo, PushInfo } from 'lib/push/send-utils.js';
+import type { PushUserInfo, PushInfo } from 'lib/push/send-utils.js';
+import { stringToVersionKey, getDevicesByPlatform } from 'lib/push/utils.js';
 import {
   type WebNotifInputData,
   webNotifInputDataValidator,
@@ -824,76 +825,6 @@
   return await createIDs('notifications', numIDsNeeded);
 }
 
-type VersionKey = {
-  +codeVersion: number,
-  +stateVersion: number,
-  +majorDesktopVersion?: number,
-};
-const versionKeyRegex: RegExp = new RegExp(/^-?\d+\|-?\d+(\|-?\d+)?$/);
-function versionKeyToString(versionKey: VersionKey): string {
-  const baseStringVersionKey = `${versionKey.codeVersion}|${versionKey.stateVersion}`;
-  if (!versionKey.majorDesktopVersion) {
-    return baseStringVersionKey;
-  }
-  return `${baseStringVersionKey}|${versionKey.majorDesktopVersion}`;
-}
-
-function stringToVersionKey(versionKeyString: string): VersionKey {
-  invariant(
-    versionKeyRegex.test(versionKeyString),
-    'should pass correct version key string',
-  );
-  const [codeVersion, stateVersion, majorDesktopVersion] = versionKeyString
-    .split('|')
-    .map(Number);
-  return { codeVersion, stateVersion, majorDesktopVersion };
-}
-
-function getDevicesByPlatform(
-  devices: $ReadOnlyArray<Device>,
-): Map<Platform, Map<string, Array<NotificationTargetDevice>>> {
-  const byPlatform = new Map<
-    Platform,
-    Map<string, Array<NotificationTargetDevice>>,
-  >();
-  for (const device of devices) {
-    let innerMap = byPlatform.get(device.platformDetails.platform);
-    if (!innerMap) {
-      innerMap = new Map<string, Array<NotificationTargetDevice>>();
-      byPlatform.set(device.platformDetails.platform, innerMap);
-    }
-    const codeVersion: number =
-      device.platformDetails.codeVersion !== null &&
-      device.platformDetails.codeVersion !== undefined
-        ? device.platformDetails.codeVersion
-        : -1;
-    const stateVersion: number = device.platformDetails.stateVersion ?? -1;
-
-    let versionsObject = { codeVersion, stateVersion };
-    if (device.platformDetails.majorDesktopVersion) {
-      versionsObject = {
-        ...versionsObject,
-        majorDesktopVersion: device.platformDetails.majorDesktopVersion,
-      };
-    }
-
-    const versionKey = versionKeyToString(versionsObject);
-    let innerMostArrayTmp: ?Array<NotificationTargetDevice> =
-      innerMap.get(versionKey);
-    if (!innerMostArrayTmp) {
-      innerMostArrayTmp = [];
-      innerMap.set(versionKey, innerMostArrayTmp);
-    }
-    const innerMostArray = innerMostArrayTmp;
-
-    innerMostArray.push({
-      cryptoID: device.cryptoID,
-      deliveryID: device.deliveryID,
-    });
-  }
-  return byPlatform;
-}
-
 type CommonNativeNotifInputData = {
   +keyserverID: string,
   +notifTexts: ResolvedNotifTexts,
diff --git a/lib/push/send-utils.js b/lib/push/send-utils.js
--- a/lib/push/send-utils.js
+++ b/lib/push/send-utils.js
@@ -1,15 +1,15 @@
 // @flow
 
-import invariant from 'invariant';
 import _pickBy from 'lodash/fp/pickBy.js';
 import uuidv4 from 'uuid/v4.js';
 
+import { generateNotifUserInfoPromise } from './utils.js';
 import { hasPermission } from '../permissions/minimally-encoded-thread-permissions.js';
 import {
   rawMessageInfoFromMessageData,
   createMessageInfo,
 } from '../shared/message-utils.js';
-import { type PushType, pushTypes } from '../shared/messages/message-spec.js';
+import { pushTypes } from '../shared/messages/message-spec.js';
 import { messageSpecs } from '../shared/messages/message-specs.js';
 import { notifTextsForMessageInfo } from '../shared/notif-utils.js';
 import {
@@ -64,82 +64,6 @@
   };
 }
 
-async function generateNotifUserInfoPromise(
-  pushType: PushType,
-  devices: $ReadOnlyArray<Device>,
-  newMessageInfos: $ReadOnlyArray<RawMessageInfo>,
-  messageDatas: $ReadOnlyArray<MessageData>,
-  threadsToMessageIndices: $ReadOnlyMap<string, number[]>,
-  threadIDs: $ReadOnlySet<string>,
-  userNotMemberOfSubthreads: Set<string>,
-  fetchMessageInfoByID: (messageID: string) => Promise<any>,
-  userID: string,
-): Promise<?{
-  devices: $ReadOnlyArray<Device>,
-  messageDatas: Array<MessageData>,
-  messageInfos: Array<RawMessageInfo>,
-}> {
-  const promises: Array<
-    Promise<?{
-      +messageInfo: RawMessageInfo,
-      +messageData: MessageData,
-    }>,
-  > = [];
-
-  for (const threadID of threadIDs) {
-    const messageIndices = threadsToMessageIndices.get(threadID);
-    invariant(messageIndices, `indices should exist for thread ${threadID}`);
-
-    promises.push(
-      ...messageIndices.map(async messageIndex => {
-        const messageInfo = newMessageInfos[messageIndex];
-        if (messageInfo.creatorID === userID) {
-          return undefined;
-        }
-
-        const { type } = messageInfo;
-        const { generatesNotifs } = messageSpecs[type];
-
-        if (!generatesNotifs) {
-          return undefined;
-        }
-
-        const messageData = messageDatas[messageIndex];
-        const doesGenerateNotif = await generatesNotifs(
-          messageInfo,
-          messageData,
-          {
-            notifTargetUserID: userID,
-            userNotMemberOfSubthreads,
-            fetchMessageInfoByID,
-          },
-        );
-
-        return doesGenerateNotif === pushType
-          ? { messageInfo, messageData }
-          : undefined;
-      }),
-    );
-  }
-
-  const messagesToNotify = await Promise.all(promises);
-  const filteredMessagesToNotify = messagesToNotify.filter(Boolean);
-
-  if (filteredMessagesToNotify.length === 0) {
-    return undefined;
-  }
-
-  return {
-    devices,
-    messageInfos: filteredMessagesToNotify.map(
-      ({ messageInfo }) => messageInfo,
-    ),
-    messageDatas: filteredMessagesToNotify.map(
-      ({ messageData }) => messageData,
-    ),
-  };
-}
-
 async function getPushUserInfo(
   messageInfos: { +[id: string]: RawMessageInfo },
   rawThreadInfos: RawThreadInfos,
diff --git a/lib/push/utils.js b/lib/push/utils.js
new file mode 100644
--- /dev/null
+++ b/lib/push/utils.js
@@ -0,0 +1,166 @@
+// @flow
+import invariant from 'invariant';
+
+import type { Device } from './send-utils.js';
+import { type PushType } from '../shared/messages/message-spec.js';
+import { messageSpecs } from '../shared/messages/message-specs.js';
+import type { Platform } from '../types/device-types.js';
+import {
+  type MessageData,
+  type RawMessageInfo,
+} from '../types/message-types.js';
+import type { NotificationTargetDevice } from '../types/notif-types.js';
+
+export type VersionKey = {
+  +codeVersion: number,
+  +stateVersion: number,
+  +majorDesktopVersion?: number,
+};
+export const versionKeyRegex: RegExp = new RegExp(/^-?\d+\|-?\d+(\|-?\d+)?$/);
+
+function versionKeyToString(versionKey: VersionKey): string {
+  const baseStringVersionKey = `${versionKey.codeVersion}|${versionKey.stateVersion}`;
+  if (!versionKey.majorDesktopVersion) {
+    return baseStringVersionKey;
+  }
+  return `${baseStringVersionKey}|${versionKey.majorDesktopVersion}`;
+}
+
+function stringToVersionKey(versionKeyString: string): VersionKey {
+  invariant(
+    versionKeyRegex.test(versionKeyString),
+    'should pass correct version key string',
+  );
+  const [codeVersion, stateVersion, majorDesktopVersion] = versionKeyString
+    .split('|')
+    .map(Number);
+  return { codeVersion, stateVersion, majorDesktopVersion };
+}
+
+function getDevicesByPlatform(
+  devices: $ReadOnlyArray<Device>,
+): Map<Platform, Map<string, Array<NotificationTargetDevice>>> {
+  const byPlatform = new Map<
+    Platform,
+    Map<string, Array<NotificationTargetDevice>>,
+  >();
+  for (const device of devices) {
+    let innerMap = byPlatform.get(device.platformDetails.platform);
+    if (!innerMap) {
+      innerMap = new Map<string, Array<NotificationTargetDevice>>();
+      byPlatform.set(device.platformDetails.platform, innerMap);
+    }
+    const codeVersion: number =
+      device.platformDetails.codeVersion !== null &&
+      device.platformDetails.codeVersion !== undefined
+        ? device.platformDetails.codeVersion
+        : -1;
+    const stateVersion: number = device.platformDetails.stateVersion ?? -1;
+
+    let versionsObject = { codeVersion, stateVersion };
+    if (device.platformDetails.majorDesktopVersion) {
+      versionsObject = {
+        ...versionsObject,
+        majorDesktopVersion: device.platformDetails.majorDesktopVersion,
+      };
+    }
+
+    const versionKey = versionKeyToString(versionsObject);
+    let innerMostArrayTmp: ?Array<NotificationTargetDevice> =
+      innerMap.get(versionKey);
+    if (!innerMostArrayTmp) {
+      innerMostArrayTmp = [];
+      innerMap.set(versionKey, innerMostArrayTmp);
+    }
+    const innerMostArray = innerMostArrayTmp;
+
+    innerMostArray.push({
+      cryptoID: device.cryptoID,
+      deliveryID: device.deliveryID,
+    });
+  }
+  return byPlatform;
+}
+
+async function generateNotifUserInfoPromise(
+  pushType: PushType,
+  devices: $ReadOnlyArray<Device>,
+  newMessageInfos: $ReadOnlyArray<RawMessageInfo>,
+  messageDatas: $ReadOnlyArray<MessageData>,
+  threadsToMessageIndices: $ReadOnlyMap<string, number[]>,
+  threadIDs: $ReadOnlySet<string>,
+  userNotMemberOfSubthreads: Set<string>,
+  fetchMessageInfoByID: (messageID: string) => Promise<any>,
+  userID: string,
+): Promise<?{
+  devices: $ReadOnlyArray<Device>,
+  messageDatas: Array<MessageData>,
+  messageInfos: Array<RawMessageInfo>,
+}> {
+  const promises: Array<
+    Promise<?{
+      +messageInfo: RawMessageInfo,
+      +messageData: MessageData,
+    }>,
+  > = [];
+
+  for (const threadID of threadIDs) {
+    const messageIndices = threadsToMessageIndices.get(threadID);
+    invariant(messageIndices, `indices should exist for thread ${threadID}`);
+
+    promises.push(
+      ...messageIndices.map(async messageIndex => {
+        const messageInfo = newMessageInfos[messageIndex];
+        if (messageInfo.creatorID === userID) {
+          return undefined;
+        }
+
+        const { type } = messageInfo;
+        const { generatesNotifs } = messageSpecs[type];
+
+        if (!generatesNotifs) {
+          return undefined;
+        }
+
+        const messageData = messageDatas[messageIndex];
+        const doesGenerateNotif = await generatesNotifs(
+          messageInfo,
+          messageData,
+          {
+            notifTargetUserID: userID,
+            userNotMemberOfSubthreads,
+            fetchMessageInfoByID,
+          },
+        );
+
+        return doesGenerateNotif === pushType
+          ? { messageInfo, messageData }
+          : undefined;
+      }),
+    );
+  }
+
+  const messagesToNotify = await Promise.all(promises);
+  const filteredMessagesToNotify = messagesToNotify.filter(Boolean);
+
+  if (filteredMessagesToNotify.length === 0) {
+    return undefined;
+  }
+
+  return {
+    devices,
+    messageInfos: filteredMessagesToNotify.map(
+      ({ messageInfo }) => messageInfo,
+    ),
+    messageDatas: filteredMessagesToNotify.map(
+      ({ messageData }) => messageData,
+    ),
+  };
+}
+
+export {
+  stringToVersionKey,
+  versionKeyToString,
+  getDevicesByPlatform,
+  generateNotifUserInfoPromise,
+};