Platform aggregator model for SMB merchants in non-US markets — guidance request

[execute25]

Hi UCP team and community,

I'm an individual developer based in South Korea, researching the feasibility of building a UCP-compliant gateway service for SMB e-commerce merchants in non-US markets. Before committing significant time to this, I'd like to clarify a few questions about the platform aggregator model, since the current merchant interest form requires US fulfillment.

Context

Korean SMB merchants (typical profile: 1-30B KRW monthly revenue, on platforms like Cafe24, Makeshop, or custom shops) generally don't have the engineering bandwidth to implement UCP directly. The pattern announced for Commerce Inc, Salesforce, and Stripe — where the platform handles the protocol layer on behalf of its merchants — seems like the right fit for this segment.

My intent is to build a similar gateway, focused on Korean SMB segment, abstracting UCP (and ACP, MCP) so merchants connect once and become available across AI surfaces.

Questions

1. Eligibility of independent platform aggregators

The recent UCP Tech Council announcements feature established platforms (Salesforce, Commerce Inc, Stripe, Shopify). Is the platform-as-aggregator model open to new entrants — i.e. an independent platform that wants to onboard merchants from a specific market segment — or is it currently limited to existing Tech Council partners and named platform integrations?

If it is open, what's the recommended path to engage with the UCP partnership program? The merchant interest form (support.google.com/merchants/contact/ucp_integration_interest) is geared toward individual merchants and US-only fulfillment.

2. Geographic timing for non-US platform integrations

The current merchant waitlist is US-only. For a platform partner specifically targeting non-US markets (in my case, South Korea), is there:

a) A roadmap or rough timeline for non-US market activation on AI Mode / Gemini?
b) A separate partnership track for platform integrators that doesn't depend on US AI Mode availability — i.e., can technical integration work begin against test environments before consumer surfaces go live in the target market?

3. Payment handlers for non-Google-Pay-native markets

The Google Pay payment handler assumes the merchant's PSP supports Google Pay tokenization. In Korea, most SMB merchants use local PG providers (e.g., 토스페이먼츠, KG이니시스, NHN KCP) that aren't currently Google Pay-integrated.

Two sub-questions:

• Is there a path to define custom payment handlers for local market PGs (similar to how com.google.pay is one of multiple possible handlers)?
• Or is the current expectation that merchants in such markets must migrate to a globally-integrated PSP (Stripe, Adyen) to participate in UCP?

4. Conformance and testing without live activation

If a platform partner can't yet activate on AI Mode in their target market, can they:

• Run conformance tests against the spec independently?
• Get a test/sandbox environment from Google to validate end-to-end flows?
• Be in a position to "go live" the day Google announces market expansion?

What I'm not asking

I'm not asking for early access or special treatment, and I understand if some answers are "wait for market expansion" or "not yet defined." I just want to avoid building toward an architecture that's incompatible with how Google envisions platform partnerships working, and to know what preparation is reasonable to do now vs. what should wait.

Happy to provide more detail on the technical approach if useful. Thanks for the great work on UCP — the protocol design is solid.

— Sejin