diff --git a/backend/src/services/picpeakExportService.js b/backend/src/services/picpeakExportService.js
index 663ca252..0fb8f469 100644
--- a/backend/src/services/picpeakExportService.js
+++ b/backend/src/services/picpeakExportService.js
@@ -76,32 +76,26 @@ async function getLatestMigration() {
   }
 }
 
-// Stream one table to <dataDir>/<table>.ndjson (one JSON object per line).
+// Write one table to <dataDir>/<table>.ndjson (one JSON object per line).
 // Returns { rowCount, checksum } for the manifest. JSON.stringify serialises
 // Dates to ISO strings, which re-import cleanly on both engines.
+//
+// Uses a plain select rather than knex `.stream()`: streaming on Postgres pulls
+// in the optional `pg-query-stream` dependency (not bundled), so it throws on
+// pg. A select works on both engines with no extra dependency. Rows are DB
+// metadata (blobs live on disk under files/), so holding a table in memory is
+// fine for the instance sizes PicPeak targets.
 async function writeTableNdjson(table, dataDir) {
   const outPath = path.join(dataDir, `${table}.ndjson`);
-  const out = fs.createWriteStream(outPath, { encoding: 'utf8' });
   const hash = crypto.createHash('sha256');
-  let rowCount = 0;
-
-  await new Promise((resolve, reject) => {
-    out.on('error', reject);
-    const stream = db(table).stream();
-    stream.on('error', reject);
-    stream.on('data', (row) => {
-      const line = `${JSON.stringify(row)}\n`;
-      hash.update(line);
-      rowCount += 1;
-      if (!out.write(line)) {
-        stream.pause();
-        out.once('drain', () => stream.resume());
-      }
-    });
-    stream.on('end', () => out.end(resolve));
+  const rows = await db(table).select('*');
+  const lines = rows.map((row) => {
+    const line = JSON.stringify(row);
+    hash.update(`${line}\n`);
+    return line;
   });
-
-  return { rowCount, checksum: hash.digest('hex') };
+  await fsp.writeFile(outPath, lines.length ? `${lines.join('\n')}\n` : '', 'utf8');
+  return { rowCount: rows.length, checksum: hash.digest('hex') };
 }
 
 // Recursively collect files under a storage subdir as { abs, rel } where rel is
diff --git a/backend/src/services/picpeakImportService.js b/backend/src/services/picpeakImportService.js
index 4b61391f..ae37455d 100644
--- a/backend/src/services/picpeakImportService.js
+++ b/backend/src/services/picpeakImportService.js
@@ -99,6 +99,30 @@ async function reinjectCurrentAdmin(trx, currentAdmin) {
   }
 }
 
+// The json/jsonb columns of a table (Postgres only). The pg driver returns
+// jsonb as parsed JS values, so on re-insert they must be serialised back to
+// valid JSON text — otherwise a scalar like the string "PicPeak" is sent
+// unquoted and pg rejects it ("invalid input syntax for type json").
+async function jsonColumnsFor(trx, table) {
+  if (!isPostgres()) return new Set();
+  const res = await trx.raw(
+    "SELECT column_name FROM information_schema.columns WHERE table_schema = 'public' AND table_name = ? AND data_type IN ('json', 'jsonb')",
+    [table]
+  );
+  return new Set(res.rows.map((r) => r.column_name));
+}
+
+function serialiseJsonColumns(rows, jsonCols) {
+  if (!jsonCols.size) return rows;
+  return rows.map((row) => {
+    const out = { ...row };
+    for (const col of jsonCols) {
+      if (out[col] !== undefined && out[col] !== null) out[col] = JSON.stringify(out[col]);
+    }
+    return out;
+  });
+}
+
 // Whole-DB replace in one transaction with FK enforcement suspended (pg:
 // session_replication_role=replica on the trx connection, reset before commit;
 // sqlite: defer_foreign_keys so checks run at commit). knex_migrations is never
@@ -113,7 +137,9 @@ async function replaceAllTables(tables, dataDir, currentAdmin) {
     }
     for (const table of tables) {
       const rows = parseNdjson(path.join(dataDir, `${table}.ndjson`));
-      if (rows.length) await trx.batchInsert(table, rows, 100);
+      if (!rows.length) continue;
+      const jsonCols = await jsonColumnsFor(trx, table);
+      await trx.batchInsert(table, serialiseJsonColumns(rows, jsonCols), 100);
     }
 
     await reinjectCurrentAdmin(trx, currentAdmin);