diff --git a/src/config/favorite-lists.ts b/src/config/favorite-lists.ts
index 9028907..2a382a8 100644
--- a/src/config/favorite-lists.ts
+++ b/src/config/favorite-lists.ts
@@ -1,4 +1,6 @@
 import { SPELL_KIND } from "@/constants/kinds";
+import type { TagStrategy } from "@/lib/favorite-tag-strategies";
+import { groupTagStrategy } from "@/lib/favorite-tag-strategies";
 
 export interface FavoriteListConfig {
   /** The replaceable list kind that stores favorites (e.g., 10777) */
@@ -7,12 +9,15 @@ export interface FavoriteListConfig {
   elementKind: number;
   /** Human-readable label for UI */
   label: string;
+  /** Override the default e/a tag strategy (derived from isAddressableKind) */
+  tagStrategy?: TagStrategy;
 }
 
 /**
  * Maps event kind → favorite list configuration.
  *
- * Tag type ("e" vs "a") is derived at runtime from isAddressableKind(elementKind).
+ * Tag type ("e" vs "a") is derived at runtime from isAddressableKind(elementKind)
+ * unless a custom tagStrategy is provided.
  * To add a new favoritable kind, just add an entry here.
  */
 export const FAVORITE_LISTS: Record<number, FavoriteListConfig> = {
@@ -31,6 +36,12 @@ export const FAVORITE_LISTS: Record<number, FavoriteListConfig> = {
     elementKind: 30030,
     label: "Emoji Sets",
   },
+  39000: {
+    listKind: 10009,
+    elementKind: 39000,
+    label: "Favorite Groups",
+    tagStrategy: groupTagStrategy,
+  },
 };
 
 /**
diff --git a/src/hooks/useFavoriteList.ts b/src/hooks/useFavoriteList.ts
index f9ba21d..0b30e2b 100644
--- a/src/hooks/useFavoriteList.ts
+++ b/src/hooks/useFavoriteList.ts
@@ -3,9 +3,7 @@ import { use$ } from "applesauce-react/hooks";
 import {
   getEventPointerFromETag,
   getAddressPointerFromATag,
-  getTagValue,
 } from "applesauce-core/helpers";
-import { getSeenRelays } from "applesauce-core/helpers/relays";
 import { EventFactory } from "applesauce-core/event-factory";
 import eventStore from "@/services/event-store";
 import accountManager from "@/services/accounts";
@@ -13,18 +11,16 @@ import { settingsManager } from "@/services/settings";
 import { publishEvent } from "@/services/hub";
 import { useAccount } from "@/hooks/useAccount";
 import { isAddressableKind } from "@/lib/nostr-kinds";
+import { eTagStrategy, aTagStrategy } from "@/lib/favorite-tag-strategies";
 import { GRIMOIRE_CLIENT_TAG } from "@/constants/app";
+import type { TagStrategy } from "@/lib/favorite-tag-strategies";
 import type { FavoriteListConfig } from "@/config/favorite-lists";
 import type { NostrEvent } from "@/types/nostr";
 import type { EventPointer, AddressPointer } from "nostr-tools/nip19";
 
-/** Compute the identity key for an event based on tag type */
-function getItemKey(event: NostrEvent, tagType: "e" | "a"): string {
-  if (tagType === "a") {
-    const dTag = getTagValue(event, "d") || "";
-    return `${event.kind}:${event.pubkey}:${dTag}`;
-  }
-  return event.id;
+export function resolveStrategy(config: FavoriteListConfig): TagStrategy {
+  if (config.tagStrategy) return config.tagStrategy;
+  return isAddressableKind(config.elementKind) ? aTagStrategy : eTagStrategy;
 }
 
 /** Extract pointers from tags of a given type */
@@ -59,31 +55,19 @@ export function getListPointers(
   return pointers;
 }
 
-/** Build a tag for adding an item to a favorite list */
-function buildTag(event: NostrEvent, tagType: "e" | "a"): string[] {
-  const seenRelays = getSeenRelays(event);
-  const relayHint = seenRelays ? Array.from(seenRelays)[0] || "" : "";
-
-  if (tagType === "a") {
-    const dTag = getTagValue(event, "d") || "";
-    const coordinate = `${event.kind}:${event.pubkey}:${dTag}`;
-    return relayHint ? ["a", coordinate, relayHint] : ["a", coordinate];
-  }
-
-  return relayHint ? ["e", event.id, relayHint] : ["e", event.id];
-}
-
 /**
  * Generic hook to read and manage a NIP-51-style favorite list.
  *
- * Tag type ("e" vs "a") is derived from the element kind using isAddressableKind().
+ * Tag format is determined by the config's tagStrategy (defaults to "e"/"a"
+ * based on isAddressableKind). Pass a custom TagStrategy for non-standard
+ * tag formats like NIP-29 "group" tags.
  */
 export function useFavoriteList(config: FavoriteListConfig) {
   const { pubkey, canSign } = useAccount();
   const [isUpdating, setIsUpdating] = useState(false);
   const isUpdatingRef = useRef(false);
 
-  const tagType = isAddressableKind(config.elementKind) ? "a" : "e";
+  const strategy = resolveStrategy(config);
 
   // Subscribe to the user's replaceable list event
   const event = use$(
@@ -92,30 +76,33 @@ export function useFavoriteList(config: FavoriteListConfig) {
     [pubkey, config.listKind],
   );
 
-  // Extract pointers from matching tags
-  const items = useMemo(
-    () => (event ? getListPointers(event, tagType) : []),
-    [event, tagType],
-  );
+  // Extract pointers from matching tags (only meaningful for e/a strategies)
+  const items = useMemo(() => {
+    if (!event) return [];
+    if (strategy.tagName === "e") return getListPointers(event, "e");
+    if (strategy.tagName === "a") return getListPointers(event, "a");
+    return [];
+  }, [event, strategy.tagName]);
 
   // Quick lookup set of item identity keys
   const itemIds = useMemo(() => {
     if (!event) return new Set<string>();
     const ids = new Set<string>();
     for (const tag of event.tags) {
-      if (tag[0] === tagType && tag[1]) {
-        ids.add(tag[1]);
+      if (tag[0] === strategy.tagName && tag[1]) {
+        const key = strategy.keyFromTag(tag);
+        if (key) ids.add(key);
       }
     }
     return ids;
-  }, [event, tagType]);
+  }, [event, strategy]);
 
   const isFavorite = useCallback(
     (targetEvent: NostrEvent) => {
-      const key = getItemKey(targetEvent, tagType);
-      return itemIds.has(key);
+      const key = strategy.getItemKey(targetEvent);
+      return key !== "" && itemIds.has(key);
     },
-    [tagType, itemIds],
+    [strategy, itemIds],
   );
 
   const toggleFavorite = useCallback(
@@ -131,18 +118,18 @@ export function useFavoriteList(config: FavoriteListConfig) {
         const currentTags = event ? event.tags.map((t) => [...t]) : [];
         const currentContent = event?.content ?? "";
 
-        const itemKey = getItemKey(targetEvent, tagType);
-        const alreadyFavorited = currentTags.some(
-          (t) => t[0] === tagType && t[1] === itemKey,
+        const itemKey = strategy.getItemKey(targetEvent);
+        if (!itemKey) return;
+
+        const alreadyFavorited = currentTags.some((t) =>
+          strategy.matchesKey(t, itemKey),
         );
 
         let newTags: string[][];
         if (alreadyFavorited) {
-          newTags = currentTags.filter(
-            (t) => !(t[0] === tagType && t[1] === itemKey),
-          );
+          newTags = currentTags.filter((t) => !strategy.matchesKey(t, itemKey));
         } else {
-          newTags = [...currentTags, buildTag(targetEvent, tagType)];
+          newTags = [...currentTags, strategy.buildTag(targetEvent)];
         }
 
         if (settingsManager.getSetting("post", "includeClientTag")) {
@@ -168,7 +155,7 @@ export function useFavoriteList(config: FavoriteListConfig) {
         setIsUpdating(false);
       }
     },
-    [canSign, config, event, tagType],
+    [canSign, config, event, strategy],
   );
 
   return {
diff --git a/src/lib/favorite-tag-strategies.test.ts b/src/lib/favorite-tag-strategies.test.ts
new file mode 100644
index 0000000..b9a9a4d
--- /dev/null
+++ b/src/lib/favorite-tag-strategies.test.ts
@@ -0,0 +1,379 @@
+import { describe, it, expect } from "vitest";
+import { SeenRelaysSymbol } from "applesauce-core/helpers/relays";
+import {
+  eTagStrategy,
+  aTagStrategy,
+  groupTagStrategy,
+} from "./favorite-tag-strategies";
+import type { NostrEvent } from "@/types/nostr";
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+function makeEvent(overrides: Partial<NostrEvent> = {}): NostrEvent {
+  return {
+    id: "abc123def456",
+    pubkey: "pub123",
+    created_at: 1700000000,
+    kind: 1,
+    tags: [],
+    content: "",
+    sig: "sig",
+    ...overrides,
+  };
+}
+
+function withSeenRelays(event: NostrEvent, relays: string[]): NostrEvent {
+  (event as any)[SeenRelaysSymbol] = new Set(relays);
+  return event;
+}
+
+// ===========================================================================
+// eTagStrategy
+// ===========================================================================
+
+describe("eTagStrategy", () => {
+  describe("getItemKey", () => {
+    it("returns the event id", () => {
+      const event = makeEvent({ id: "deadbeef" });
+      expect(eTagStrategy.getItemKey(event)).toBe("deadbeef");
+    });
+  });
+
+  describe("buildTag", () => {
+    it("returns [e, id] when no seen relays", () => {
+      const event = makeEvent({ id: "deadbeef" });
+      expect(eTagStrategy.buildTag(event)).toEqual(["e", "deadbeef"]);
+    });
+
+    it("includes relay hint from seen relays", () => {
+      const event = withSeenRelays(makeEvent({ id: "deadbeef" }), [
+        "wss://relay.example.com/",
+      ]);
+      expect(eTagStrategy.buildTag(event)).toEqual([
+        "e",
+        "deadbeef",
+        "wss://relay.example.com/",
+      ]);
+    });
+  });
+
+  describe("matchesKey", () => {
+    it("matches when tag[0]=e and tag[1]=key", () => {
+      expect(eTagStrategy.matchesKey(["e", "abc"], "abc")).toBe(true);
+    });
+
+    it("does not match different key", () => {
+      expect(eTagStrategy.matchesKey(["e", "abc"], "xyz")).toBe(false);
+    });
+
+    it("does not match different tag type", () => {
+      expect(eTagStrategy.matchesKey(["a", "abc"], "abc")).toBe(false);
+    });
+  });
+
+  describe("keyFromTag", () => {
+    it("returns tag[1] for e tags", () => {
+      expect(eTagStrategy.keyFromTag(["e", "abc", "relay"])).toBe("abc");
+    });
+
+    it("returns undefined for non-e tags", () => {
+      expect(eTagStrategy.keyFromTag(["a", "abc"])).toBeUndefined();
+    });
+
+    it("returns undefined for empty e tag", () => {
+      expect(eTagStrategy.keyFromTag(["e"])).toBeUndefined();
+    });
+  });
+});
+
+// ===========================================================================
+// aTagStrategy
+// ===========================================================================
+
+describe("aTagStrategy", () => {
+  describe("getItemKey", () => {
+    it("returns kind:pubkey:d-tag coordinate", () => {
+      const event = makeEvent({
+        kind: 30023,
+        pubkey: "author1",
+        tags: [["d", "my-article"]],
+      });
+      expect(aTagStrategy.getItemKey(event)).toBe("30023:author1:my-article");
+    });
+
+    it("handles missing d-tag gracefully", () => {
+      const event = makeEvent({ kind: 30023, pubkey: "author1" });
+      expect(aTagStrategy.getItemKey(event)).toBe("30023:author1:");
+    });
+  });
+
+  describe("buildTag", () => {
+    it("returns [a, coordinate] when no seen relays", () => {
+      const event = makeEvent({
+        kind: 30617,
+        pubkey: "pub1",
+        tags: [["d", "repo-id"]],
+      });
+      expect(aTagStrategy.buildTag(event)).toEqual(["a", "30617:pub1:repo-id"]);
+    });
+
+    it("includes relay hint from seen relays", () => {
+      const event = withSeenRelays(
+        makeEvent({
+          kind: 30617,
+          pubkey: "pub1",
+          tags: [["d", "repo-id"]],
+        }),
+        ["wss://relay.example.com/"],
+      );
+      expect(aTagStrategy.buildTag(event)).toEqual([
+        "a",
+        "30617:pub1:repo-id",
+        "wss://relay.example.com/",
+      ]);
+    });
+  });
+
+  describe("matchesKey", () => {
+    it("matches when tag[0]=a and tag[1]=key", () => {
+      expect(
+        aTagStrategy.matchesKey(
+          ["a", "30617:pub1:repo-id"],
+          "30617:pub1:repo-id",
+        ),
+      ).toBe(true);
+    });
+
+    it("does not match different coordinate", () => {
+      expect(
+        aTagStrategy.matchesKey(
+          ["a", "30617:pub1:repo-id"],
+          "30617:pub1:other",
+        ),
+      ).toBe(false);
+    });
+
+    it("does not match different tag type", () => {
+      expect(
+        aTagStrategy.matchesKey(
+          ["e", "30617:pub1:repo-id"],
+          "30617:pub1:repo-id",
+        ),
+      ).toBe(false);
+    });
+  });
+
+  describe("keyFromTag", () => {
+    it("returns tag[1] for a tags", () => {
+      expect(aTagStrategy.keyFromTag(["a", "30617:pub1:repo"])).toBe(
+        "30617:pub1:repo",
+      );
+    });
+
+    it("returns undefined for non-a tags", () => {
+      expect(aTagStrategy.keyFromTag(["e", "abc"])).toBeUndefined();
+    });
+  });
+});
+
+// ===========================================================================
+// groupTagStrategy
+// ===========================================================================
+
+describe("groupTagStrategy", () => {
+  describe("getItemKey", () => {
+    it("returns normalizedRelayUrl'groupId", () => {
+      const event = withSeenRelays(
+        makeEvent({
+          kind: 39000,
+          tags: [["d", "bitcoin-dev"]],
+        }),
+        ["wss://groups.nostr.com/"],
+      );
+      expect(groupTagStrategy.getItemKey(event)).toBe(
+        "wss://groups.nostr.com/'bitcoin-dev",
+      );
+    });
+
+    it("normalizes relay URL without protocol", () => {
+      const event = withSeenRelays(
+        makeEvent({
+          kind: 39000,
+          tags: [["d", "test-group"]],
+        }),
+        ["groups.nostr.com"],
+      );
+      expect(groupTagStrategy.getItemKey(event)).toBe(
+        "wss://groups.nostr.com/'test-group",
+      );
+    });
+
+    it("returns empty string when no seen relays", () => {
+      const event = makeEvent({
+        kind: 39000,
+        tags: [["d", "bitcoin-dev"]],
+      });
+      expect(groupTagStrategy.getItemKey(event)).toBe("");
+    });
+
+    it("handles missing d-tag", () => {
+      const event = withSeenRelays(makeEvent({ kind: 39000 }), [
+        "wss://groups.nostr.com/",
+      ]);
+      expect(groupTagStrategy.getItemKey(event)).toBe(
+        "wss://groups.nostr.com/'",
+      );
+    });
+  });
+
+  describe("buildTag", () => {
+    it("returns [group, groupId, normalizedRelay]", () => {
+      const event = withSeenRelays(
+        makeEvent({
+          kind: 39000,
+          tags: [["d", "bitcoin-dev"]],
+        }),
+        ["wss://groups.nostr.com/"],
+      );
+      expect(groupTagStrategy.buildTag(event)).toEqual([
+        "group",
+        "bitcoin-dev",
+        "wss://groups.nostr.com/",
+      ]);
+    });
+
+    it("normalizes relay URL in built tag", () => {
+      const event = withSeenRelays(
+        makeEvent({
+          kind: 39000,
+          tags: [["d", "test-group"]],
+        }),
+        ["Groups.Nostr.COM"],
+      );
+      const tag = groupTagStrategy.buildTag(event);
+      expect(tag[2]).toBe("wss://groups.nostr.com/");
+    });
+
+    it("returns tag without relay when no seen relays", () => {
+      const event = makeEvent({
+        kind: 39000,
+        tags: [["d", "bitcoin-dev"]],
+      });
+      const tag = groupTagStrategy.buildTag(event);
+      expect(tag).toEqual(["group", "bitcoin-dev"]);
+    });
+  });
+
+  describe("matchesKey", () => {
+    it("matches with normalized relay URL", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "bitcoin-dev", "wss://groups.nostr.com/"],
+          "wss://groups.nostr.com/'bitcoin-dev",
+        ),
+      ).toBe(true);
+    });
+
+    it("normalizes relay URL in tag for comparison", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "bitcoin-dev", "groups.nostr.com"],
+          "wss://groups.nostr.com/'bitcoin-dev",
+        ),
+      ).toBe(true);
+    });
+
+    it("handles wss:// vs no-protocol mismatch", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "test", "wss://relay.example.com/"],
+          "wss://relay.example.com/'test",
+        ),
+      ).toBe(true);
+    });
+
+    it("handles ws:// protocol", () => {
+      // ws:// stays as ws:// after normalization
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "test", "ws://relay.example.com/"],
+          "ws://relay.example.com/'test",
+        ),
+      ).toBe(true);
+    });
+
+    it("does not match different group id", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "bitcoin-dev", "wss://groups.nostr.com/"],
+          "wss://groups.nostr.com/'other-group",
+        ),
+      ).toBe(false);
+    });
+
+    it("does not match different relay", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "bitcoin-dev", "wss://groups.nostr.com/"],
+          "wss://other-relay.com/'bitcoin-dev",
+        ),
+      ).toBe(false);
+    });
+
+    it("does not match non-group tags", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["e", "bitcoin-dev", "wss://groups.nostr.com/"],
+          "wss://groups.nostr.com/'bitcoin-dev",
+        ),
+      ).toBe(false);
+    });
+
+    it("returns false when tag has no relay", () => {
+      expect(
+        groupTagStrategy.matchesKey(
+          ["group", "bitcoin-dev"],
+          "wss://groups.nostr.com/'bitcoin-dev",
+        ),
+      ).toBe(false);
+    });
+  });
+
+  describe("keyFromTag", () => {
+    it("returns normalizedRelayUrl'groupId", () => {
+      expect(
+        groupTagStrategy.keyFromTag([
+          "group",
+          "bitcoin-dev",
+          "wss://groups.nostr.com/",
+        ]),
+      ).toBe("wss://groups.nostr.com/'bitcoin-dev");
+    });
+
+    it("normalizes relay URL in tag", () => {
+      expect(
+        groupTagStrategy.keyFromTag([
+          "group",
+          "bitcoin-dev",
+          "groups.nostr.com",
+        ]),
+      ).toBe("wss://groups.nostr.com/'bitcoin-dev");
+    });
+
+    it("returns undefined for non-group tags", () => {
+      expect(groupTagStrategy.keyFromTag(["e", "abc"])).toBeUndefined();
+    });
+
+    it("returns undefined for group tag without relay", () => {
+      expect(
+        groupTagStrategy.keyFromTag(["group", "bitcoin-dev"]),
+      ).toBeUndefined();
+    });
+
+    it("returns undefined for group tag without groupId", () => {
+      expect(groupTagStrategy.keyFromTag(["group"])).toBeUndefined();
+    });
+  });
+});
diff --git a/src/lib/favorite-tag-strategies.ts b/src/lib/favorite-tag-strategies.ts
new file mode 100644
index 0000000..6e9a44e
--- /dev/null
+++ b/src/lib/favorite-tag-strategies.ts
@@ -0,0 +1,109 @@
+import { getTagValue } from "applesauce-core/helpers";
+import { getSeenRelays } from "applesauce-core/helpers/relays";
+import { normalizeRelayURL } from "@/lib/relay-url";
+import type { NostrEvent } from "@/types/nostr";
+
+/** Abstracts tag format so useFavoriteList works with e, a, group, or future tag types. */
+export interface TagStrategy {
+  /** The tag name used in the list event (e.g., "e", "a", "group") */
+  tagName: string;
+  /** Compute an identity key for the given event (used in the membership set) */
+  getItemKey(event: NostrEvent): string;
+  /** Build a complete tag array for adding an event to the list */
+  buildTag(event: NostrEvent): string[];
+  /** Check if a stored tag matches a given identity key */
+  matchesKey(tag: string[], key: string): boolean;
+  /** Extract the identity key directly from a stored tag (for building itemIds set) */
+  keyFromTag(tag: string[]): string | undefined;
+}
+
+function firstSeenRelay(event: NostrEvent): string {
+  const relays = getSeenRelays(event);
+  return relays ? Array.from(relays)[0] || "" : "";
+}
+
+/** Strategy for "e" tags — regular (non-addressable) events. */
+export const eTagStrategy: TagStrategy = {
+  tagName: "e",
+  getItemKey(event) {
+    return event.id;
+  },
+  buildTag(event) {
+    const relay = firstSeenRelay(event);
+    return relay ? ["e", event.id, relay] : ["e", event.id];
+  },
+  matchesKey(tag, key) {
+    return eTagStrategy.keyFromTag(tag) === key;
+  },
+  keyFromTag(tag) {
+    return tag[0] === "e" && tag[1] ? tag[1] : undefined;
+  },
+};
+
+/** Strategy for "a" tags — addressable (parameterized replaceable) events. */
+export const aTagStrategy: TagStrategy = {
+  tagName: "a",
+  getItemKey(event) {
+    const dTag = getTagValue(event, "d") || "";
+    return `${event.kind}:${event.pubkey}:${dTag}`;
+  },
+  buildTag(event) {
+    const dTag = getTagValue(event, "d") || "";
+    const coordinate = `${event.kind}:${event.pubkey}:${dTag}`;
+    const relay = firstSeenRelay(event);
+    return relay ? ["a", coordinate, relay] : ["a", coordinate];
+  },
+  matchesKey(tag, key) {
+    return aTagStrategy.keyFromTag(tag) === key;
+  },
+  keyFromTag(tag) {
+    return tag[0] === "a" && tag[1] ? tag[1] : undefined;
+  },
+};
+
+/**
+ * Strategy for "group" tags — NIP-29 relay-based groups (kind 10009 lists).
+ *
+ * Identity is `normalizedRelayUrl'groupId` to match the pattern used by
+ * useNip29GroupList and the NIP-29 adapter.
+ */
+export const groupTagStrategy: TagStrategy = {
+  tagName: "group",
+  getItemKey(event) {
+    const groupId = getTagValue(event, "d") || "";
+    const relay = firstSeenRelay(event);
+    if (!relay) return "";
+    try {
+      return `${normalizeRelayURL(relay)}'${groupId}`;
+    } catch {
+      return "";
+    }
+  },
+  buildTag(event) {
+    const groupId = getTagValue(event, "d") || "";
+    const relay = firstSeenRelay(event);
+    if (!relay) {
+      console.warn(
+        "[useFavoriteList] Cannot build group tag: no seen relay for event",
+        event.id,
+      );
+      return ["group", groupId];
+    }
+    try {
+      return ["group", groupId, normalizeRelayURL(relay)];
+    } catch {
+      return ["group", groupId, relay];
+    }
+  },
+  matchesKey(tag, key) {
+    return groupTagStrategy.keyFromTag(tag) === key;
+  },
+  keyFromTag(tag) {
+    if (tag[0] !== "group" || !tag[1] || !tag[2]) return undefined;
+    try {
+      return `${normalizeRelayURL(tag[2])}'${tag[1]}`;
+    } catch {
+      return undefined;
+    }
+  },
+};