# Walmart Marketplace setup for PopMCP You end up pasting the Client ID and Client Secret of your own seller key pair from the Walmart Developer Portal, plus the word production or sandbox for the Environment field. - Auth: API credentials - Setup time: 5 min - API base URL: https://marketplace.walmartapis.com/v3 - Credentials screen: https://developer.walmart.com/account/api-keys - Provider docs: https://developer.walmart.com/us-marketplace/docs/authentication-authorization ## Approval required before this works Walmart must approve your Marketplace seller application (or approve your company through the Solution Provider programme) before Seller Center exists for you. The developer docs state plainly that you must 'ensure you are approved to sell your items on Walmart Marketplace' before you can reach the keys. - Typical wait: Walmart publishes no SLA for the seller application - the developer docs and Marketplace Learn state no timeframe. Seller-community reports cluster around 5-10 business days, with clean US applications sometimes clearing in 24-48 hours and mismatched or incomplete ones running several weeks. Treat any specific number as unofficial. - Cost: Free to apply - Walmart charges no setup or monthly Marketplace fee. Referral fees (a percentage of each sale, varying by category) apply once you are live. - Blocked until approved: Everything. The Client ID and Client Secret live in the Developer Portal, which you sign into with Seller Center credentials via Seller Center > API Integration > API Key Management. No approved seller account means no Seller Center login, so no key pair, so no OAuth token - and Items, Orders, Inventory, Prices, Reports and the sandbox all sit behind that same token. - Works meanwhile: Read-only preparation. The developer.walmart.com reference, the API Explorer and the published Postman collections are public, so you can write and shape request/response handling against the documented schemas. You cannot execute a single authenticated call, sandbox included. ## Before you begin - A live US Walmart Marketplace seller account with Seller Center access - Seller Center sign-in credentials, which are what the Developer Portal asks for when you click API Key Management - Admin-level access in Seller Center so you can open the API Integration page - Production keys exist only for a launched seller account. A Dynamic sandbox key pair is separate and cannot be used against production ## Get your credentials ### 1. Open API Key Management from Seller Center Sign in to Seller Center, open the API Integration page at `seller.walmart.com/api-key`, and select API Key Management. Sign in to the Developer Portal with your Seller Center credentials when prompted. Screen: https://seller.walmart.com/api-key ### 2. Find your own key pair on My Account → API Keys On My Account → API Keys, locate your personal key pair, which has a lock icon next to it. Ignore rows without a lock, which belong to solution providers you have authorized. Screen: https://developer.walmart.com/account/api-keys ### 3. Copy the Client ID and Client Secret Click Show beside the secret on the locked row. Copy the Client ID and the Client Secret into PopMCP. Screen: https://developer.walmart.com/us-marketplace/docs/authentication-authorization ### 4. Set the Environment field to match the key Leave Environment as `production` for a live seller key. Enter `sandbox` only if the pair you copied is a Dynamic sandbox key. Screen: https://developer.walmart.com/us-marketplace/docs/dynamic-sandbox ## Fields PopMCP asks for - Auth type (connectionType): Walmart Marketplace uses OAuth client-credentials. Create the key in Seller Center → Developer Portal → API Key Management. We only ever store the Client ID / Client Secret (encrypted) and mint short-lived tokens from them server-side. - Client ID (clientId) [required]: From Seller Center → Developer Portal → API Key Management. Make sure it matches the environment you pick below. - Client Secret (clientSecret) [required]: The secret paired with your Client ID. Stored encrypted; used server-side only to mint short-lived access tokens. - Environment (environment): Leave as "production" for a live Walmart seller account. Enter "sandbox" only if your Client ID / Client Secret is a Sandbox key. A sandbox key will not work against production, or vice-versa. ## Verify PopMCP shows the Walmart Marketplace connector as Connected and lists your seller id together with a recent orders count, confirming a token was minted from the token endpoint. ## Troubleshooting ### 401 Unauthorized on every call Cause: The Client ID and Client Secret belong to a different environment than the one selected, or were copied from an unlocked solution-provider row. Fix: Recopy from the row with the lock icon on My Account → API Keys and match Environment to the key, production with production and sandbox with sandbox. ### Token works, then stops after a few minutes Cause: Walmart access tokens are valid for 15 minutes (900 seconds). Fix: Nothing to do, PopMCP refreshes tokens server-side. If it persists, reconnect so a fresh token is minted. ### Sandbox calls return production-shaped errors Cause: The request was not routed to the Dynamic sandbox. Fix: Set Environment to sandbox so PopMCP sends the WM_SANDBOX: v2 header and targets https://sandbox.walmartapis.com. ### No key pair is listed at all Cause: The seller account has not been launched, or you signed in with a user that is not attached to the seller account. Fix: Start from seller.walmart.com/api-key with the Seller Center account that owns the marketplace listing, then select API Key Management again. --- Source: https://www.docs.popmcp.com/docs/integrations/walmart/