diff --git a/deno.json b/deno.json
index c5ab1de..cef5364 100644
--- a/deno.json
+++ b/deno.json
@@ -6,7 +6,8 @@
     "server:prod": "deno run --allow-net --allow-read --allow-write --allow-env --allow-ffi --unstable-ffi server.ts",
     "migrate": "deno run --allow-net --allow-read --allow-write --allow-env --allow-ffi --unstable-ffi src/migrations/init.ts",
     "webhooks": "deno run --allow-net --allow-env scripts/manage-webhooks.ts",
-    "webhooks:all": "deno run --allow-net --allow-env scripts/list-all-webhooks.ts"
+    "webhooks:all": "deno run --allow-net --allow-env scripts/list-all-webhooks.ts",
+    "backfill:search": "deno run --allow-net --allow-read --allow-write --allow-env --allow-ffi --unstable-ffi scripts/backfill-opensearch.ts"
   },
   "imports": {
     "@db/sqlite": "jsr:@db/sqlite@^0.13.0",
diff --git a/scripts/backfill-opensearch.ts b/scripts/backfill-opensearch.ts
new file mode 100644
index 0000000..d273687
--- /dev/null
+++ b/scripts/backfill-opensearch.ts
@@ -0,0 +1,125 @@
+// Backfill OpenSearch from each known user's PDS.
+//
+//   deno task backfill:search
+//
+// Reads distinct DIDs from the local SQLite database, resolves each DID's PDS
+// via the PLC directory, paginates `com.atproto.repo.listRecords` for
+// `space.remanso.note`, and indexes every record into OpenSearch.
+//
+// Requires OPENSEARCH_URL to be set; falls back to a no-op otherwise.
+// SQLite path follows the same SQLITE_PATH convention as the server/jetstream.
+
+import { db } from "../src/data/db.ts";
+import { resolvePds } from "../src/auth/verify.ts";
+import { ensureIndex, indexNote } from "../src/search/opensearch.ts";
+import { log } from "../src/log.ts";
+
+type ListRecordsResponse = {
+  records: { uri: string; value: Record<string, unknown> }[];
+  cursor?: string;
+};
+
+const COLLECTION = "space.remanso.note";
+const PAGE_SIZE = 100;
+
+const rkeyFromUri = (uri: string): string => {
+  const parts = uri.split("/");
+  return parts[parts.length - 1];
+};
+
+const backfillDid = async (
+  did: string,
+): Promise<{ indexed: number; failed: number }> => {
+  let indexed = 0;
+  let failed = 0;
+  const pds = await resolvePds(did);
+  let cursor: string | undefined = undefined;
+
+  do {
+    const url = new URL(`${pds}/xrpc/com.atproto.repo.listRecords`);
+    url.searchParams.set("repo", did);
+    url.searchParams.set("collection", COLLECTION);
+    url.searchParams.set("limit", String(PAGE_SIZE));
+    if (cursor) url.searchParams.set("cursor", cursor);
+
+    const res = await fetch(url);
+    if (!res.ok) {
+      throw new Error(`listRecords ${did}: ${res.status} ${await res.text()}`);
+    }
+    const page = (await res.json()) as ListRecordsResponse;
+
+    for (const record of page.records) {
+      const rkey = rkeyFromUri(record.uri);
+      const value = record.value as {
+        title?: string;
+        content?: string;
+        language?: string;
+        discoverable?: boolean;
+        publishedAt?: string;
+        createdAt?: string;
+      };
+      if (!value.title) {
+        failed++;
+        log(`[backfill] skip ${did}/${rkey}: missing title`);
+        continue;
+      }
+      try {
+        await indexNote({
+          did,
+          rkey,
+          title: value.title,
+          content: value.content,
+          language: value.language,
+          discoverable: value.discoverable,
+          publishedAt: value.publishedAt,
+          createdAt: value.createdAt,
+        });
+        indexed++;
+      } catch (error) {
+        failed++;
+        log(`[backfill] index ${did}/${rkey} failed:`, error);
+      }
+    }
+
+    cursor = page.cursor;
+  } while (cursor);
+
+  return { indexed, failed };
+};
+
+const main = async () => {
+  if (!Deno.env.get("OPENSEARCH_URL")) {
+    console.error("OPENSEARCH_URL is not set; aborting backfill.");
+    Deno.exit(1);
+  }
+
+  try {
+    await ensureIndex();
+  } catch (error) {
+    console.error("Failed to ensure index:", error);
+    Deno.exit(1);
+  }
+
+  const rows = db.prepare("SELECT DISTINCT did FROM note ORDER BY did").all<
+    { did: string }
+  >();
+  log(`[backfill] ${rows.length} DID(s) to process`);
+
+  let totalIndexed = 0;
+  let totalFailed = 0;
+  for (const { did } of rows) {
+    try {
+      const { indexed, failed } = await backfillDid(did);
+      log(`[backfill] ${did}: indexed=${indexed} failed=${failed}`);
+      totalIndexed += indexed;
+      totalFailed += failed;
+    } catch (error) {
+      log(`[backfill] ${did} aborted:`, error);
+      totalFailed++;
+    }
+  }
+  log(`[backfill] done. indexed=${totalIndexed} failed=${totalFailed}`);
+  db.close();
+};
+
+await main();