March 23, 2026

No One Owns the Full Stack Anymore

March 17-23, 2026 - Five major moves in seven days. The agentic commerce stack is assembling fast.

Last week we covered OpenAI killing Instant Checkout and what it meant for the industry. This week, the rest of the industry responded. And the speed is striking.

In seven days: Perplexity won its appeal, every Shopify store became discoverable in ChatGPT by default, Visa signed up 21 European banks for AI agent payments, Walmart confirmed its AI agent is going multi-platform, and Sam Altman’s other company launched a tool to prove there’s a human behind every AI agent.

Here’s what happened and what it means.

Perplexity’s injunction reversed - Comet stays on Amazon (for now)

Seven days after a federal judge blocked Perplexity’s Comet from accessing Amazon, a 9th Circuit Court of Appeals panel suspended the injunction on March 17. Judges Eric Miller and Patrick Bumatay ruled that Comet can continue operating while the full appeal is considered.

This doesn’t settle the case. A preliminary injunction is not a final judgment, and an appeal suspension is not a reversal. But the speed matters - it took only seven days for the appeals court to intervene, suggesting the panel sees genuine legal questions about whether terms of service alone can block AI agents that users explicitly authorize.

Why it matters for merchants: The consent-vs-authorization question we covered last week is genuinely unsettled. If the appeals court eventually rules that user consent overrides platform terms of service, every merchant’s ability to block unauthorized AI agents gets weaker. If it upholds the original injunction, terms of service become the primary defense. Either way, merchants should have a clear agent access policy - and should be watching this case.

Every Shopify store now appears in ChatGPT by default

On March 17, Shopify confirmed that all Shopify stores will be discoverable inside ChatGPT by default in late March - no app installation required. ChatGPT already has over 800 million weekly active users. Products are surfaced through the Shopify Catalog, and purchases complete on the merchant’s own storefront (in-app browser on mobile, separate tab on web).

This is a direct consequence of OpenAI’s checkout pivot. With Instant Checkout gone, ChatGPT now sends users to merchant sites. Shopify built the bridge: merchants’ product data flows into ChatGPT automatically, and the checkout experience stays on the Shopify storefront.

Why it matters for merchants: If you’re on Shopify, you’re now in ChatGPT whether you intended to be or not. Your product data quality just became a ChatGPT discoverability factor. Products with thin descriptions, missing attributes, or poor structured data will lose to competitors whose listings are complete. Check your feed now - this is no longer theoretical.

Walmart’s Sparky AI goes multi-platform

Walmart’s EVP of AI Acceleration, Daniel Danker, confirmed that Walmart’s Sparky AI assistant will operate inside ChatGPT starting the week of March 25, with Gemini integration following. Customers who use Sparky have 35% higher order value than non-users.

This is the retailer-branded-agent-inside-AI-platform model that OpenAI’s checkout pivot made the default. Instead of ChatGPT handling checkout, Walmart brings its own AI agent into ChatGPT. The customer talks to Sparky within a ChatGPT conversation, gets Walmart-specific product recommendations, and checks out through Walmart’s systems.

Why it matters for merchants: Walmart embedding Sparky in ChatGPT and Gemini simultaneously confirms that the biggest retailers aren’t betting on a single AI platform. They’re going multi-protocol, multi-platform. Independent merchants can’t build custom AI agents for every platform - but they can make sure their product data is complete enough that generic discovery algorithms surface their products alongside the giants.

Visa launches “Agentic Ready” with 21 European banks

On March 17, Visa launched Visa Agentic Ready, a structured program for banks to test AI agent-initiated payments. It launches in Europe first with 21 issuing partners including Barclays, HSBC UK, Revolut, Santander, Commerzbank, Nationwide, Nexi, Raiffeisen Bank International, and DZ Bank.

The technical approach: tokenization (substituting real card numbers with digital codes that AI agents can use) plus biometric authentication. Santander completed a fully autonomous AI agent book purchase as a proof of concept using a Visa credential.

This comes two weeks after Santander and Mastercard completed Europe’s first live AI agent payment. The pattern is clear: European agentic commerce payments infrastructure is being built by banks and card networks, not by AI companies.

Program	Partners	Scope	Status
Visa Agentic Ready	21 European banks	AI agent payment testing	Launched March 17
Mastercard Agent Pay	Santander	First live AI agent payment in Europe	Completed March 2
Nexi + Google Cloud	UCP/AP2 infrastructure	European agentic commerce rails	MoU signed March 3
Spreedly	Payments platform	Agentic commerce as live channel	Live since March 4

Why it matters for merchants: The European payments layer for agentic commerce is materializing fast. Four separate infrastructure programs launched in March. European merchants who assumed agentic commerce was “a US thing” need to recalibrate - 31% of French shoppers are already using AI to buy. The checkout rails are being built. Discovery readiness becomes the merchant’s problem - and it’s urgent.

World launches AgentKit: proving there’s a human behind the AI

On March 17, World (Sam Altman’s identity verification company) released AgentKit, a tool that proves a real human is behind an AI shopping agent. It uses World ID (derived from iris scans) to generate encrypted verification codes. When an AI agent tries to add items to a cart or check out, the merchant can request a one-time human-approval signal tied to a unique person.

AgentKit integrates with x402, a stablecoin micropayment protocol developed by Coinbase and Cloudflare. It’s a direct response to the central tension in the Amazon-Perplexity case: how do you distinguish a human-authorized AI agent from an autonomous bot?

Why it matters for merchants: Identity verification for AI agents is a new layer that didn’t exist a month ago. If merchants can verify that a real, consenting human is behind an AI agent, the consent-vs-authorization debate gets simpler. AgentKit is one answer to that problem - though how many merchants will adopt iris-scan-based verification from a crypto-adjacent company remains to be seen.

Klarna joins Google’s UCP - the multi-protocol bet

Klarna joined Google’s Universal Commerce Protocol, adding buy-now-pay-later to the UCP payment stack. Klarna already runs its own Agentic Product Protocol (launched December 2025) giving AI agents access to 100M+ products across 12 markets. With this move, Klarna supports ACP (OpenAI/Stripe), UCP (Google), and its own protocol simultaneously.

Why it matters for merchants: Klarna’s multi-protocol strategy is instructive. The company isn’t betting on one protocol winning. It’s making itself available everywhere AI agents shop. Merchants who use Klarna as a payment option get some agentic commerce coverage almost for free. But the product data quality question remains - Klarna can process the payment, but your product still needs to be discoverable first.

The bigger picture

Zoom out and the week tells a coherent story. The agentic commerce stack is assembling in layers:

Discovery layer: ChatGPT, Gemini, Perplexity. All three now function as product research engines. Shopify’s default integration means millions of products are now discoverable. The question for merchants is no longer “should I be in these channels?” but “is my data good enough to compete?”

Agent layer: Walmart’s Sparky, retailer apps in ChatGPT, Perplexity’s Comet. AI agents that act on behalf of users - whether authorized or not - are proliferating. World’s AgentKit is an early attempt to solve the trust problem.

Payment layer: Visa (21 banks), Mastercard (Santander), Stripe (SPTs), Klarna (multi-protocol). The checkout infrastructure is being built by payments companies, confirming what OpenAI’s retreat made obvious: AI companies shouldn’t own checkout.

Legal layer: Amazon v. Perplexity remains the test case. The appeals reversal keeps the question open. The outcome will define whether merchants or users control AI agent access.

Each layer is being built by different companies. No one owns the full stack anymore - which is exactly what OpenAI tried and failed to do.

What merchants should do this week

1. If you’re on Shopify, check your ChatGPT visibility. Your products are going into ChatGPT by default. Make sure your product data - titles, descriptions, attributes, images - is ready for AI discovery. Use our previewer.

2. If you’re in Europe, pay attention. Four separate payment infrastructure programs launched in March. European agentic commerce is no longer “coming soon” - the rails are being tested now.

3. Review your terms of service. The Perplexity appeal means the legal framework is still in flux. Clear terms about automated access give you legal standing regardless of which way the case goes.

4. Don’t pick a protocol winner. Klarna’s multi-protocol approach is the right model. Prepare your product data for all channels, not just one. See our full UCP vs ACP comparison for what that means in practice.