Challenge

Global appetite for Japanese anime merchandise, collectibles, and trading cards has surged in recent years, amplified by streaming services. Mercari, one of Japan's largest marketplace, was well positioned to meet that demand. Since scaling up in 2019, its cross-border business has grown 15x to nearly ¥100 billion in annual GMV, about 9% of Mercari's total.

As demand accelerated, the limitations of Mercari's cross-border model became increasingly clear. A buyer outside Japan couldn't purchase directly on Mercari. Instead, a third-party purchasing agent bought items on their behalf and shipped them internationally. The arrangement gave Mercari little control over the customer experience or pricing. Buyers also faced language barriers, complicated purchasing processes, and trust concerns when dealing with unfamiliar third-party platforms. Mercari had more than four billion cumulative listings, but no direct way to put them in front of international customers.

Mercari launched its Global App in September 2025 to allow overseas buyers to purchase directly, starting with Taiwan and Hong Kong. For a marketplace where sellers only ship after a payment is completed, every redirect to an agent's site was a chance for the buyer to abandon the purchase. "For customers using Mercari, being unexpectedly sent to an external purchasing agent's site made them uneasy," said Takahiro Masaki, Manager of Cross Border Business Development at Mercari. "The steps were complicated, and it felt neither safe nor simple. Looking back, that was the biggest problem in our purchase flow."

The company needed a single payment partner that could support dozens of countries from its Japan entity while enabling local currencies and payment methods. That partner also needed to provide strong fraud detection across markets and integrate fast enough to match Mercari’s plan to expand to more than 50 countries by 2028.

Solution

Alongside its purchasing-agent channel, Mercari chose Stripe to build a checkout experience directly into the Global App using Stripe’s in-app payment element. Buyers now complete checkout entirely within Mercari's app, without being redirected to a third-party site. The in-app payment element uses prebuilt UI components to enable Mercari to launch a fully localized checkout in each market without building payment forms from scratch. "Small differences in the UI can shift conversion by 3-4%," said Masaki. "Not having to tune that ourselves is a bigger benefit than we expected."

Mercari partnered with Stripe’s professional services team to build a scalable, resilient payment system capable of supporting rapid growth. Stripe provided expertise on the technical implementation, working closely with Mercari to understand its architecture and business logic and delivering a highly detailed, customized integration guide.
The Stripe team also hosted workshops to design Mercari’s multicurrency cross-border funds flow scenarios for payments, refunds, and chargebacks. In addition, Stripe helped Mercari implement a conversion system using the FX Quotes API, so Mercari can show buyers prices in their local currency at current exchange rates while controlling its own margins and spreads.

International transactions carry higher fraud risk for Mercari than domestic ones, and its previous setup offered limited visibility into those risks. With Stripe Radar and 3D Secure, Mercari applies fraud screening to every transaction. Mercari sets its 3D Secure strategy by country, applying it to every payment in Taiwan, where cardholders are used to authentication, and taking a risk-based approach in the US, where buyers expect a faster checkout. "We didn't have expertise in international payments," said Masaki. "When we didn't know what criteria to use to control fraud, Stripe's global data became our compass."

Stripe professional services also worked with Mercari’s internal fraud prevention team on how to integrate Radar into existing fraud operations and systems. Stripe provided training on Radar, reporting, and the Stripe dashboard to help the team prepare for the complexities of managing fraud across international markets.

The engineering team pushed for Stripe, too. "Some of our engineers had built with Stripe at previous companies, so support for Stripe was strong," said Masaki. "They valued how thorough the API documentation was and how quickly they could find what they needed. In the end, their strong recommendation is what got us to adopt it."

Results

Payment success rate improves by double digits after in-app checkout launch

With checkout now fully embedded inside the Global App, Mercari improved its payment success rate by double digits compared with the redirect flow. Buyers can now browse, purchase, and track shipments in a single experience.

Three markets go live without local entities

Mercari launched the Global App in Taiwan and Hong Kong. It processes transactions through Stripe in each buyer's local currency, converting prices from Japanese yen at real-time exchange rates. Buyers see transparent pricing, and Mercari manages foreign exchange risk on every transaction.

Taiwan has been a strong early market for 3D Secure, where authentication is already familiar to consumers. As a result, applying 3D Secure to 100% of transactions had minimal impact on conversion.

With payments running smoothly, Mercari moved quickly. In June 2026, it launched the Global App in the United States, its second-largest cross-border market by transaction volume. The company plans to reach more than 50 countries by 2028, deploying in new markets first to validate demand before deciding whether to establish local entities.