Becoming AI‑Native at Mercari: Group Strategy and a US Case Study

How we’re transforming our products, culture, and ways of working with AI

We at Mercari US Engineering previously shifted to publishing on our corporate site, but to once again share our technological advancements and engineering culture more widely and quickly with the global community, we’re returning to this blog.

At the Group level, we are embedding AI into product development and operations to improve velocity, quality, and customer experience. With this post, we aim to introduce our Mercari Group’s transformation toward becoming AI-Native, highlight the US business’s strategic positioning, and showcase a recent contribution from the US team at Mercari GEARS 2025.

We first outline the Group’s AI‑Native strategy, then show how Mercari US applies it through an end‑to‑end testing initiative.

Mercari Group’s AI-Native Transformation

This transformation is already producing significant results Group-wide:

• Engineering Output: We achieved a dramatic 64% year-over-year increase in output per engineer involved in development.
• AI Adoption: 95% of Mercari employees are already using AI tools.
• Code Generation: 70% of code generated for product development involves AI.

We see this is an opportunity for exponential growth, aiming for 10x or 100x gains, ultimately believing that AI will “unleash us from the bottlenecks and resource limitations that previously held us back.”

(Source: “Back to Startup” and “AI-Native” — The Next Chapter in Mercari’s Journey at 12 Years)

AI Strategy and Product Innovation

The Group’s strategy focuses on transforming core processes and enhancing user experience and platform reliability:

Product Experience: Our core vision is achieving lower friction for users listing or purchasing items. For example, in Japan, we introduced AI Listing, which automatically generates item descriptions from uploaded photos. We also leverage image recognition to suggest optimal categories and prices, simplifying the entire listing process.

Platform Security: To manage the new risks associated with generative AI/LLM technology, Mercari formed an AI security team in May 2025. This specialized team is dedicated to handling issues such as those outlined in frameworks like the OWASP 2025 Top 10 Risks for Generative AI. (Source: How Mercari’s AI Security Team is Securing AI Native)

These initiatives embody our AI-Native philosophy where every improvement, from user experience to infrastructure, leverages AI at its core.

Mercari US: Building a Hassle-Free Marketplace

At Mercari US, we apply the Group’s AI‑Native principles to improve unit economics and customer experience. We translate these principles into day‑to‑day product decisions and operational improvements for sustainable growth in the US market.

Our core mission in the US is: To build the go-to marketplace for hassle-free selling and discovering deals.

To realize sustainable growth, our strategy focuses on:

• Enhancing the product’s core experience.
• Using AI to innovate our UI/UX.
• Pursuing category‑specific strategies to better serve distinct buyer and seller needs.

Mercari US at Mercari GEARS 2025

Mercari GEARS 2025, our Group’s technical conference, recently took place in Japan. The event showcased our technology, organization, and culture — including the evolution of our AI-Native initiatives.

At the event, Gleb Bahmutov from the US team delivered a presentation titled “Running 1000 End-to-End Web Tests Daily.” He shared how Mercari US scaled its end-to-end testing pipeline to run over thousands of E2E tests efficiently per day by parallelizing workloads, tagging and selectively running tests, and even using AI to help determine which tests to execute.

This approach not only accelerated our release cycle but also demonstrated how AI and automation can drive smarter, faster, and more reliable development workflows ; an embodiment of our AI-Native mindset in action.

[embed]

Our Commitment to the AI-Native Future

The shift to AI-Native means moving towards an exciting future where AI becomes deeply integrated into our daily work.

The challenge ahead isn’t just about using AI ; it’s about shifting how we think and work. We need to stay curious, take on new challenges, and not be limited by what we’ve already built.

We will continue to share outcomes and methods as we scale these practices.