Documentation

Everything you need to get SellerBeam running. Setup takes about 10 minutes.

1. Requirements

Before starting, make sure you have the following:

  • An active Amazon Seller Central account (Individual or Professional)
  • Node.js v18 or later installed on your machine
  • Google Chrome browser
  • Basic comfort with running commands in a terminal

2. SP-API Credentials

SellerBeam uses the Amazon Selling Partner API (SP-API). You need to register as a developer and create an app to obtain credentials. Your credentials are never sent to any server — they stay in a local .env file on your machine.

Step 1: Register as a developer

  1. Go to Seller Central and sign in.
  2. Navigate to Apps & Services → Develop Apps.
  3. Click Add new app client and fill in the app name and description.
  4. Select your use case (Private Seller — for personal use).

Step 2: Obtain your credentials

After creating your app, collect the following values:

LWA_CLIENT_IDYour app's Login with Amazon Client ID
LWA_CLIENT_SECRETYour app's Login with Amazon Client Secret
REFRESH_TOKENGenerated when you authorize the app for your seller account
SELLER_IDYour Merchant Token, found in Seller Central → Account Info
MARKETPLACE_IDATVPDKIKX0DER for the US marketplace (see list below for others)

Marketplace IDs

USATVPDKIKX0DER
UKA1F83G8C2ARO7P
DEA1PA6795UKMFR9
CAA2EUQ1WTGCTBG2

3. Local Server Setup

The local server is a small Node.js + Express application that handles SP-API authentication and serves data to the Chrome extension. It runs on localhost:3001.

Installation

# Download and extract the server package
# (see the Chrome Web Store listing for the download link)

# Install dependencies
npm install

# Copy the environment template
cp .env.example .env

Edit the .env file and fill in your credentials (see Environment Variables Reference below).

Starting the server

npm start
# Server running on http://localhost:3001

Keep this terminal window open while you source. The extension won't load data if the server isn't running.

4. Chrome Extension Install

  1. Make sure the local server is running on localhost:3001.
  2. Install SellerBeam from the Chrome Web Store.
  3. Pin the extension to your Chrome toolbar.
  4. Navigate to any Amazon product page (e.g. amazon.com/dp/B0XXXXXX).
  5. The SellerBeam sidebar should appear automatically on the right side of the page.

5. Environment Variables Reference

All variables go in the .env file in the server directory.

# Amazon SP-API credentials
LWA_CLIENT_ID=amzn1.application-oa2-client.xxxxx
LWA_CLIENT_SECRET=xxxxx
REFRESH_TOKEN=Atzr|xxxxx
SELLER_ID=XXXXXXXXXXXXX
MARKETPLACE_ID=ATVPDKIKX0DER

# Server config (optional, default: 3001)
PORT=3001

6. Troubleshooting

Sidebar doesn't appear on Amazon product pages

Check that the local server is running (npm start in the server directory). The extension requires the server to be active on localhost:3001.

Error: 'Unauthorized' or 401 response

Your SP-API credentials are incorrect or expired. Double-check your LWA_CLIENT_ID, LWA_CLIENT_SECRET, and REFRESH_TOKEN in the .env file.

Gated/ungated check shows an error

This endpoint requires your Seller ID to be correct. Verify it matches your Merchant Token in Seller Central → Account Info.

Fees show as $0 or N/A

Amazon's Product Fees API may not have data for this ASIN in your marketplace. This can occur for some product types.

Still stuck? Email us at contact@sellerbeam.com with a description of the issue and the error message you're seeing.