diff --git a/.changeset/defer-until-thread.md b/.changeset/defer-until-thread.md
new file mode 100644
index 00000000..84944405
--- /dev/null
+++ b/.changeset/defer-until-thread.md
@@ -0,0 +1,5 @@
+---
+"@plotday/twister": minor
+---
+
+Added: `NewNote.deferUntilThread` holds a note addressed by `{ source }` until a thread with that source exists, instead of returning `null` when it has not synced yet.
diff --git a/twister/src/plot.ts b/twister/src/plot.ts
index 4c4d4b92..0b9d6b09 100644
--- a/twister/src/plot.ts
+++ b/twister/src/plot.ts
@@ -869,6 +869,35 @@ export type NewNote = Partial<
      */
     authoredBySelf?: boolean;
 
+    /**
+     * Keep this note until its thread exists, instead of dropping it.
+     *
+     * A note addressed by `{ source }` normally resolves immediately, and
+     * `saveNote` returns `null` when no thread carries that source — which for
+     * a connector usually means the item this note belongs to has not synced
+     * yet. Set this to have the platform hold the note and attach it as soon
+     * as a thread with that source appears, rather than making you store and
+     * retry it yourself.
+     *
+     * Recommended for any `{ source }`-addressed note whose target is synced
+     * by a different product or connector and may therefore lag. Leave it
+     * unset when a miss means the note is genuinely undeliverable: `null` is
+     * then the signal you want, and holding the note would accumulate payloads
+     * for a thread that will never arrive.
+     *
+     * Held notes are dropped after a bounded retry window. Ordering is not
+     * guaranteed relative to notes that attached immediately, so set `created`
+     * (as connectors already should) rather than relying on arrival order.
+     *
+     * At most one UNKEYED held note survives per `{ source }`: two deferred
+     * notes without a `key` addressed to the same still-unresolved source
+     * collapse onto a single held slot, and the second one you save silently
+     * replaces the first — it does not queue as a second note. If you may
+     * defer more than one note to the same unresolved source, give each a
+     * distinct `key` so they are held separately.
+     */
+    deferUntilThread?: boolean;
+
     /**
      * Format of the note content. Determines how the note is processed:
      * - 'text': Plain text that will be converted to markdown (auto-links URLs, preserves line breaks)