UI server started from Node Neo shows “Initialization Error (RangeError: Offset is outside the bounds of the DataView)”

[liuxingpluck]

UI server started from Node Neo shows “Initialization Error (RangeError: Offset is outside the bounds of the DataView)” when visiting http://localhost:9913

Starting the DuckDB UI via SQL from a Node.js app works (the local HTTP server starts and becomes reachable), but opening the page shows an “Initialization Error” with RangeError: Offset is outside the bounds of the DataView. The UI also displays User ID: unknown and User E-mail: unknown. Since the local URL is reachable, the server is up; the failure happens in the UI initialization.

Steps to Reproduce

1. Create a DuckDB connection from a Node.js app using duckdb-node-neo.

2. Execute the following SQL:
   SET ui_local_port = 9913;
   CALL start_ui_server();

3. Open http://localhost:9913/ (or http://127.0.0.1:9913/) in Chrome.

4. Observe the error screen.

Screenshot:

Expected Behavior:
The DuckDB UI should load normally and allow running queries against the local DuckDB instance, without requiring any MotherDuck sign-in for local mode. (Docs say the UI runs locally by default and port is configurable.)

Environment
OS: Windows 11 WSL2 ubuntu24

Node.js: v24.6

@duckdb/node-api v1.3.2

Browser: Chrome 139

Database location: local file

Minimal Repro (SQL):
Executed from a Node.js script using Node Neo; any client that can run SQL should reproduce.

SET ui_local_port = 9913;
CALL start_ui_server();
-- then open http://localhost:9913 in a browser

According to docs, CALL start_ui_server() starts the embedded HTTP server and ui_local_port picks the port.
DuckDB

What I Tried
Different ports (e.g., 4213 / 9913) → same result.
Reload / clear cache → no change.
UI server restarts (CALL stop_ui_server(); then start again) → still failing.

Notes
Docs indicate the UI’s assets are fetched from a remote server by default (https://ui.duckdb.org). Perhaps the frontend bundle or persisted state parsing is failing during initialization (the error mentions DataView). Any guidance on additional logs to collect from the browser console or the Node process would be appreciated.
DuckDB
GitHub

Additional Context
This is a local DuckDB session (not signed into MotherDuck). The page mentions MotherDuck in the error UI, but I’m only trying to use the local UI. If there’s any configuration I should set in Node Neo when starting the UI, please let me know.

[jraymakers]

Are you keeping the Node script alive after starting the UI? If not, then the DuckDB instance and hence the UI HTTP server will shut down, which could lead to this error.

As an example, the following script successfully launches the UI from a Node script. Note the use of readline to keep the process alive.

import { DuckDBConnection } from '@duckdb/node-api';
import readline from 'node:readline/promises';

const connection = await DuckDBConnection.create();

await connection.run('install ui; load ui; call start_ui();');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});
await rl.question(`Press return to exit`);
rl.close();