diff --git a/keyserver/src/responders/website-responders.js b/keyserver/src/responders/website-responders.js
--- a/keyserver/src/responders/website-responders.js
+++ b/keyserver/src/responders/website-responders.js
@@ -48,7 +48,13 @@
 import { promiseAll } from 'lib/utils/promises.js';
 import { defaultNotifPermissionAlertInfo } from 'lib/utils/push-alerts.js';
 import { infoFromURL } from 'lib/utils/url-utils.js';
-import { tBool, tNumber, tShape, tString } from 'lib/utils/validation-utils.js';
+import {
+  tBool,
+  tNumber,
+  tShape,
+  tString,
+  ashoatKeyserverID,
+} from 'lib/utils/validation-utils.js';
 import getTitle from 'web/title/getTitle.js';
 import { navInfoValidator } from 'web/types/nav-types.js';
 import { navInfoFromURL } from 'web/url-utils.js';
@@ -495,6 +501,15 @@
     };
   })();
 
+  const keyserverStorePromise = (async () => {
+    const sessionID = await sessionIDPromise;
+    return {
+      keyserverInfos: {
+        [ashoatKeyserverID]: { cookie: undefined, sessionID },
+      },
+    };
+  })();
+
   const {
     jsURL,
     fontsURL,
@@ -596,7 +611,7 @@
     commServicesAccessToken: null,
     inviteLinksStore: inviteLinksStorePromise,
     lastCommunicatedPlatformDetails: {},
-    keyserverStore: { keyserverInfos: {} },
+    keyserverStore: keyserverStorePromise,
   });
   const validatedInitialReduxState = validateOutput(
     viewer.platformDetails,
diff --git a/lib/types/keyserver-types.js b/lib/types/keyserver-types.js
--- a/lib/types/keyserver-types.js
+++ b/lib/types/keyserver-types.js
@@ -9,6 +9,7 @@
 // See https://linear.app/comm/issue/ENG-4347/stop-using-browser-cookies
 export type KeyserverInfo = {
   +cookie?: ?string,
+  +sessionID?: ?string,
 };
 
 export type KeyserverStore = {
@@ -18,6 +19,7 @@
 export const keyserverInfoValidator: TInterface<KeyserverInfo> =
   tShape<KeyserverInfo>({
     cookie: t.maybe(t.String),
+    sessionID: t.maybe(t.String),
   });
 
 export const keyserverStoreValidator: TInterface<KeyserverStore> =
diff --git a/lib/utils/sanitization.js b/lib/utils/sanitization.js
--- a/lib/utils/sanitization.js
+++ b/lib/utils/sanitization.js
@@ -295,14 +295,23 @@
   state: AppState,
   redactionHelpers: RedactionHelpers,
 ): AppState {
-  const keyserverInfos = { ...state.keyserverStore.keyserverInfos };
-  for (const key in keyserverInfos) {
-    if (keyserverInfos[key].cookie === undefined) {
-      continue;
-    }
-    keyserverInfos[key] = { ...keyserverInfos[key], cookie: null };
-  }
-  const keyserverStore = { ...state.keyserverStore, keyserverInfos };
+  const { keyserverInfos } = state.keyserverStore;
+  const keyserverInfosCopy = Object.fromEntries(
+    Object.keys(keyserverInfos).map(key => [
+      key,
+      keyserverInfos[key].cookie === undefined
+        ? keyserverInfos[key]
+        : {
+            ...keyserverInfos[key],
+            cookie: null,
+          },
+    ]),
+  );
+  const keyserverStore = {
+    ...state.keyserverStore,
+    keyserverInfos: keyserverInfosCopy,
+  };
+
   state = { ...state, keyserverStore };
 
   if (state.deviceToken !== undefined && state.deviceToken !== null) {