# MCP and APIs for ecommerce: How AI assistants reach your store data > An API is an interface developers build against in code. An MCP server exposes the same functionality as tools an AI assistant can call in plain language. Here is how the two layers differ, and when an ecommerce team uses each. How AI assistants reach store data, and why the API underneath does not go away ## What an API does The two are often presented as competing options. They are layers, and most ecommerce teams end up using both. This guide explains what each one actually does, when to reach for which, and what to check before connecting an AI assistant to live store data. ## What an MCP server does An API and an MCP server are two ways into the same ecommerce data. An API is an interface developers build against in code, and it is how a feature gets into a live storefront. An MCP server exposes that same functionality as tools an AI assistant can call in plain language, so a person can ask a question and get an answer without writing anything. Underneath, the MCP server is calling that same API. ## API and MCP server: Side by side Store data now has a second audience, and it is machines. Shopping assistants read catalogs to advise buyers. Merchant-side agents read store data to decide what to send and when. Our guide to agentic commerce covers both, and both need data a machine can reach and make sense of. ## When to use which An API is a contract. It defines the exact requests a system accepts and the exact responses it returns, so that other software can rely on it. When a shopper types into a search box and results appear, an API call produced those results. When a product feed syncs overnight, an API call moved the data. ## How this works at Hello Retail Hello Retail runs both layers. The REST and GraphQL APIs are what integrations are built against, and the Hello Retail MCP server connects AI assistants to the same functionality. It works with Claude (Code, Desktop, and Projects), OpenAI Codex, and ChatGPT. ## Why the distinction between MCP and API matters now ## Ask your store a question The strength of an API is that it is deterministic. The same request returns the same shape of response every time, which is what makes it safe to put in front of customers. The cost is that every question has to be expressed as code first. Someone has to know the endpoint, write the request, handle the response, and deploy it. For a one-off question about last week's search behavior, that is a lot of work for a small answer. ## Frequently asked questions ### What is the difference between an MCP server and an API? An API is an interface that software calls in code. A developer writes against it to build a feature into a storefront, an app, or a backend job, and that code runs the same way every time. An MCP server sits on top of the same functionality and exposes it as tools an AI assistant can call in plain language. The assistant decides which tools to use and in what order, based on the question a person asked. You use the API to build something into your store, and the MCP server to ask something of it. ### Does an MCP server replace an API? No. An MCP server needs an underlying API to call. It is an additional access layer for AI assistants, not a replacement for the programmatic interface. Anything that has to run reliably in production, a storefront search box, a checkout flow, a nightly product feed sync, still belongs in code against the API. Hello Retail documents both, side by side, for exactly this reason. ### What can an ecommerce team do with an MCP server? Ask questions of live store data without opening a dashboard, and get answers assembled from several sources in one request. Typical examples are finding which searches return no results, checking whether the last product feed synced, seeing which fields are searchable and sortable, and reading or editing a search or recommendation template. The Hello Retail MCP server exposes seven documented tool categories: website management, search, search analytics, feeds, product data, data fields, and recommendations. ### Is it safe to connect an AI assistant to ecommerce data? It depends on how the server is built. The two things to check are whose access the assistant is using and what it is allowed to change. On the Hello Retail MCP server you sign in with your own Hello Retail account, and the assistant then acts on your behalf with the same access that account already has, so there is no separate key to issue or share. Most of its tools are read-only, and the write-enabled tools, such as editing a search or recommendation template, ask for confirmation before they run. ### Which AI assistants can connect to an ecommerce MCP server? That is set by the server. The Hello Retail MCP server works with Claude (Code, Desktop, and Projects), OpenAI Codex, and ChatGPT. Because the Model Context Protocol is an open standard, any assistant that implements it can, in principle, connect to any server that implements it. ### Do we need developers to use an MCP server? Not to use it day to day. Someone technical usually does the first connection, since it needs a Company ID and an OAuth login, but the questions afterwards are asked in ordinary language. That is the practical difference from an API, where every question has to be turned into code before it can be answered. --- For the full interactive experience, visit [helloretail.com/en/learn/mcp-vs-api-ecommerce](https://helloretail.com/en/learn/mcp-vs-api-ecommerce) ## About Hello Retail Hello Retail is an AI-powered ecommerce personalization platform based in Copenhagen, Denmark. We help online retailers improve search, recommendations, merchandising, email, and retail media through our proprietary Product Intelligence engine. - **Website**: [helloretail.com](https://helloretail.com) - **Demo**: [Book a Demo](https://helloretail.com/en/demo/) - **AI information**: [helloretail.com/en/ai-info](https://helloretail.com/en/ai-info) --- *This content is optimized for LLM consumption.*