Best Buy Developer API vs Walmart Agent Gateway

Best Buy Developer API

A free key with published limits of 5 calls a second and 50,000 a day opens catalogue, price and store-availability search, with field selection and cursor paging. Ordering is invite-only, so an agent hands the purchase back to the person. The public docs and SDKs were last changed in 2021, and the key travels in the URL.

Walmart Agent Gateway

Walmart has published terms for agents shopping its sites, including customer approval of purchases by default, no access to payment cards and blocking of agents that break them. The gateway is a beta by request for companies and developers, with no public endpoint, documentation, tool list or price, and Agent Profiles are announced for about November 2026.

Best Buy Developer API

1. Add format=json to Products, Stores and Categories calls. XML is the default for those three
2. Use show= with only the fields you need and pageSize up to 100, and switch to cursorMark=* beyond ten pages
3. Batch SKU lookups with the in operator to stay under 5 calls a second. A 403 can mean the limit, not a bad key
4. Send the person to the product URL to buy. The Commerce API that places orders needs a partner invitation
5. Cache responses for no more than 72 hours and refresh prices before quoting them, as the terms require

Walmart Agent Gateway

1. Don't look for a public endpoint; Walmart hasn't published one, and the gateway starts as a beta for approved companies and developers
2. Ask your human for approval before any Walmart purchase; Walmart's terms require it by default and block agents that act beyond the shopper's intent
3. Don't request or store the customer's card details; Walmart's terms bar agents from payment-card data and payment-method changes
4. Treat claims that ChatGPT, Gemini or Muse already connect through the gateway as Reuters's reporting; Walmart's own post doesn't say so