diff --git a/apps/web/src/components/views/settings/Notifications.tsx b/apps/web/src/components/views/settings/Notifications.tsx
index 1d8803759b..ff2a2945e3 100644
--- a/apps/web/src/components/views/settings/Notifications.tsx
+++ b/apps/web/src/components/views/settings/Notifications.tsx
@@ -53,6 +53,7 @@ import { SettingsSubsection } from "./shared/SettingsSubsection";
 import { doesRoomHaveUnreadMessages } from "../../../Unread";
 import SettingsFlag from "../elements/SettingsFlag";
 import { onSubmitPreventDefault } from "../../../utils/form.ts";
+import { keywordRuleId } from "../../../models/notificationsettings/keywordRuleId.ts";
 
 // TODO: this "view" component still has far too much application logic in it,
 // which should be factored out to other files.
@@ -565,13 +566,16 @@ export default class Notifications extends React.PureComponent<EmptyObject, ISta
                 ruleVectorState = existingRuleVectorState ?? VectorState.On; //default
             }
             const kind = PushRuleKind.ContentSpecific;
+            const ruleIds = new Set(originalRules.map((r) => r.rule_id));
             for (const word of diff.added) {
-                await MatrixClientPeg.safeGet().addPushRule("global", kind, word, {
+                const ruleId = keywordRuleId(word, ruleIds);
+                ruleIds.add(ruleId);
+                await MatrixClientPeg.safeGet().addPushRule("global", kind, ruleId, {
                     actions: PushRuleVectorState.actionsFor(ruleVectorState),
                     pattern: word,
                 });
                 if (ruleVectorState === VectorState.Off) {
-                    await MatrixClientPeg.safeGet().setPushRuleEnabled("global", kind, word, false);
+                    await MatrixClientPeg.safeGet().setPushRuleEnabled("global", kind, ruleId, false);
                 }
             }
 
diff --git a/apps/web/src/models/notificationsettings/keywordRuleId.ts b/apps/web/src/models/notificationsettings/keywordRuleId.ts
new file mode 100644
index 0000000000..987ab1dba8
--- /dev/null
+++ b/apps/web/src/models/notificationsettings/keywordRuleId.ts
@@ -0,0 +1,31 @@
+/*
+Copyright 2026 hayaksi1
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+/**
+ * Work out which rule ID a keyword should be stored under.
+ *
+ * A keyword is normally its own rule ID, but homeservers reserve the IDs beginning with a dot for
+ * the rules they define themselves and refuse to store any other, so a keyword such as
+ * `...push complete` cannot be one. The ID drops those leading dots; the rule's pattern, which is
+ * what messages are actually matched against, keeps the keyword exactly as it was typed. That can
+ * leave two keywords wanting the same ID, so one of them is numbered off the end.
+ *
+ * @param keyword - The keyword as the user typed it.
+ * @param existingIds - The rule IDs already in use.
+ * @returns A rule ID the homeserver will accept and no other rule is using.
+ */
+export function keywordRuleId(keyword: string, existingIds: Iterable<string>): string {
+    // A keyword of nothing but dots leaves nothing to name the rule after.
+    const base = keyword.replace(/^\.+/, "") || "keyword";
+
+    const taken = new Set(existingIds);
+    if (!taken.has(base)) return base;
+
+    let suffix = 2;
+    while (taken.has(`${base}-${suffix}`)) suffix++;
+    return `${base}-${suffix}`;
+}
diff --git a/apps/web/src/models/notificationsettings/reconcileNotificationSettings.ts b/apps/web/src/models/notificationsettings/reconcileNotificationSettings.ts
index fdf4f4925b..f32cfbeae7 100644
--- a/apps/web/src/models/notificationsettings/reconcileNotificationSettings.ts
+++ b/apps/web/src/models/notificationsettings/reconcileNotificationSettings.ts
@@ -15,6 +15,7 @@ import { RoomNotifState } from "../../RoomNotifs";
 import { type NotificationSettings } from "./NotificationSettings";
 import { type PushRuleDiff, type PushRuleUpdate } from "./PushRuleDiff";
 import { buildPushRuleMap } from "./PushRuleMap";
+import { keywordRuleId } from "./keywordRuleId";
 
 function toStandardRules(
     model: NotificationSettings,
@@ -225,9 +226,12 @@ export function reconcileNotificationSettings(
         }
         newKeywords.delete(rule.pattern!);
     }
+    const ruleIds = new Set(contentRules.map((rule) => rule.rule_id));
     for (const keyword of newKeywords) {
+        const ruleId = keywordRuleId(keyword, ruleIds);
+        ruleIds.add(ruleId);
         changes.added.push({
-            rule_id: keyword,
+            rule_id: ruleId,
             kind: PushRuleKind.ContentSpecific,
             default: false,
             enabled: model.mentions.keywords,
diff --git a/apps/web/test/unit-tests/components/views/settings/Notifications-test.tsx b/apps/web/test/unit-tests/components/views/settings/Notifications-test.tsx
index 864ca485fa..c0468a2166 100644
--- a/apps/web/test/unit-tests/components/views/settings/Notifications-test.tsx
+++ b/apps/web/test/unit-tests/components/views/settings/Notifications-test.tsx
@@ -858,6 +858,20 @@ describe("<Notifications />", () => {
             });
         });
 
+        it("adds a keyword that starts with a dot", async () => {
+            await getComponentAndWait();
+
+            await userEvent.type(screen.getByLabelText("Keyword"), ".jest");
+
+            fireEvent.click(screen.getByText("Add"));
+
+            // The homeserver rejects a rule id beginning with a dot, so only the pattern keeps it.
+            expect(mockClient.addPushRule).toHaveBeenCalledWith("global", PushRuleKind.ContentSpecific, "jest", {
+                actions: [PushRuleActionName.Notify, { set_tweak: "highlight", value: false }],
+                pattern: ".jest",
+            });
+        });
+
         it("adds a new keyword with same actions as existing rules when keywords rule is off", async () => {
             const offContentRule = {
                 ...bananaRule,
diff --git a/apps/web/test/unit-tests/models/notificationsettings/NotificationSettings-test.ts b/apps/web/test/unit-tests/models/notificationsettings/NotificationSettings-test.ts
index a51540129b..79045eb20f 100644
--- a/apps/web/test/unit-tests/models/notificationsettings/NotificationSettings-test.ts
+++ b/apps/web/test/unit-tests/models/notificationsettings/NotificationSettings-test.ts
@@ -215,4 +215,29 @@ describe("NotificationSettings", () => {
         expect(pendingChanges.deleted).toHaveLength(0);
         expect(pendingChanges.updated).toHaveLength(0);
     });
+
+    it("stores a keyword that starts with a dot under an id the server will accept", async () => {
+        const pushRules = (await import("./pushrules_default.json")) as IPushRules;
+        const model = { ...DefaultNotificationSettings, keywords: ["...push complete"] };
+
+        const pendingChanges = reconcileNotificationSettings(pushRules, model, false);
+
+        expect(pendingChanges.added).toEqual([
+            expect.objectContaining({
+                kind: PushRuleKind.ContentSpecific,
+                rule_id: "push complete",
+                pattern: "...push complete",
+            }),
+        ]);
+    });
+
+    it("keeps the ids of two keywords that differ only by a leading dot apart", async () => {
+        const pushRules = (await import("./pushrules_default.json")) as IPushRules;
+        const model = { ...DefaultNotificationSettings, keywords: ["banana", ".banana"] };
+
+        const pendingChanges = reconcileNotificationSettings(pushRules, model, false);
+
+        expect(pendingChanges.added.map((rule) => rule.rule_id)).toEqual(["banana", "banana-2"]);
+        expect(pendingChanges.added.map((rule) => rule.pattern)).toEqual(["banana", ".banana"]);
+    });
 });