PowerSync DevTools for Node.js

A Node.js app has no dev server, so your app process serves DevTools and you open it in a browser.

Requirements

@powersync/node.
Node.js 20.16 or later.

Set Up DevTools

Install the package

npm install -D @powersync/diagnostics

Enable DevTools in your app

After you create the database, call enablePowerSyncDiagnostics() in development only.

import { PowerSyncDatabase } from '@powersync/node';

const db = new PowerSyncDatabase({ schema: AppSchema, database: { dbFilename: 'app.db' } });
await db.connect(connector, { diagnostics: true });

if (process.env.NODE_ENV !== 'production') {
  const { enablePowerSyncDiagnostics } = await import('@powersync/diagnostics/node');
  const devtools = await enablePowerSyncDiagnostics(db);
  console.log(`PowerSync DevTools: ${devtools.signInUrl}`);
}

Import @powersync/diagnostics inside the check. A production install without dev dependencies (npm ci --omit=dev) does not include the package. A static import at the top of the file then stops your app at startup.diagnostics: true is optional. Without it, the Buckets tab does not show the total number of operations for each bucket.

Open the sign-in link

Start your app and open the link that it prints. The link contains a one-time code that is valid for five minutes and for one browser. If the code expires, open devtools.url to print a new link in the terminal.

To see what each tab is for, read Using DevTools. To connect a coding agent to the MCP endpoint at <url>/__mcp, read MCP Tools.

Options

Pass options as the second argument: enablePowerSyncDiagnostics(db, { port: 4000 }).

Option	Default	Description
`port`	A random free port	The port that DevTools listens on. A random port makes DevTools harder for other websites to find.
`host`	`localhost`	The host that the server binds to.
`auth`	`true`	If `true`, the browser must sign in with a one-time code. If `false`, any browser on your machine can open DevTools.
`open`	`false`	If `true`, DevTools opens in your browser when the server starts.
`sdk`	`@powersync/node`	The SDK label that the UI shows.
`id`	`node-1`	The database ID that the UI and the MCP tools show.
`mcp`	`'auto'`	The MCP endpoint setting. See MCP Tools.

If you set host to an address other than localhost, other devices on your network can reach DevTools, which can read and change your local data. In that case, keep auth set to true.

Return Value

enablePowerSyncDiagnostics() returns an object with these properties:

Property	Description
`url`	The address of DevTools, such as `http://localhost:51234`.
`signInUrl`	The link to open. It contains the one-time code. If `auth` is `false`, it is the same as `url`.
`close()`	Stops the server and detaches the database.

Get Started

Configuration Details

Sync Streams

Client SDKs

Handling Writes

Maintenance & Ops

Integrations

Tools

Resources

PowerSync DevTools for Node.js

Requirements

Set Up DevTools

Options

Return Value

​Requirements

​Set Up DevTools

​Options

​Return Value

Requirements

Set Up DevTools

Options

Return Value