Mercadona Replaces Eight Years of Algolia With an In-House Search Engine Built on Claude Code

Mercadona Tech has replaced Algolia, its search provider of eight years, with an internal engine built using Anthropic's Claude Code, a system that now handles 4.4 million searches a week and drives 30 to 35% of products added to carts.

Search is one of those pieces of infrastructure that quietly decides a huge share of e-commerce revenue without ever getting much attention, and swapping out an eight-year incumbent provider is not a decision most retail tech teams make lightly. Mercadona's own numbers suggest the replacement was not a lateral move: a third of cart additions now trace back to a system the company built itself rather than licensed.

Eight years replaced in weeks

What makes the story notable is not just that it happened, but how fast. The build took about a month end to end, with 70% of the core work done in three days, a timeline that would have been difficult to imagine for a production search engine replacement even two years ago. Two and a half people shipped what the original scoping called a five to six month project, and did it while running a live retail platform underneath millions of weekly searches.

“What makes the story notable is not just that it happened, but how fast.”

The cost shift is just as striking. Monthly spend dropped from a $9,000 to $15,000 range down to under $900, an order-of-magnitude reduction that turns a recurring vendor line item into something closer to a rounding error.

For a GTM leader, the headline number is not the cost or even the conversion lift, it is the team size. Two and a half people replacing a five-to-six-month, five-to-six-person build is the kind of ratio that changes how a company scopes its next internal build versus buy decision.