Autonomous checkout has moved from demo to disputed business model within a single year. Amazon’s Rufus-powered “Buy for Me” now completes purchases on external retailer sites on a shopper’s behalf. OpenAI tried a native 4% checkout fee inside ChatGPT and pulled it after six months. A new startup, Natural, has raised $30 million to build payment rails specifically for AI agents, arguing that card and ACH rails still require a human to authorize the final payment step even after an agent has done the vendor comparison. The three companies are testing three different answers to the same question: when the “customer” is software, who captures the margin?
Amazon: Zero Commission, for Now
Amazon’s Buy for Me feature, which launched in beta in April 2025, lets its Rufus assistant (renamed Alexa for Shopping in the US as of May 13, 2026) locate a product on an external retailer’s site and complete the purchase using the customer’s stored Amazon payment and shipping details. The order still routes through Amazon’s checkout, order tracking, and A-to-Z guarantee. As of its beta phase, Amazon does not charge a commission on Buy for Me purchases. By March 2026, the underlying Shop Direct program had grown to more than 100 million products from over 400,000 merchants, with “tens of millions” of items eligible for Buy for Me’s agentic checkout.
That zero-commission structure sits in sharp contrast to Amazon’s standard marketplace economics, where third-party sellers typically pay an 8-15% referral fee on top of separate fulfillment and advertising costs. Buy for Me does not touch that fee structure because the products aren’t sold on Amazon’s marketplace. They’re purchased from the brand’s own site, with Amazon acting as the payment and logistics intermediary rather than the merchant of record. The commercial upside for Amazon isn’t a transaction fee; it’s keeping the checkout relationship, the order history, and the customer inside the Amazon account even when the product isn’t Amazon’s own inventory. Some external retailers, however, have objected that Amazon is completing purchases on their websites without prior authorization.
OpenAI: The Toll Booth That Didn’t Scale
OpenAI launched Instant Checkout inside ChatGPT on September 29, 2025, built on the Agentic Commerce Protocol (ACP) co-developed with Stripe. The model was explicit: OpenAI charged merchants a 4% transaction fee on every completed purchase, layered on top of Stripe’s standard processing costs (roughly 2.9% + $0.30). Etsy went live on day one; Shopify brands including Glossier, SKIMS, Spanx, and Vuori followed. PayPal joined as a payment provider on October 28, 2025.
On March 4-5, 2026, OpenAI reversed course. According to Shopify president Harley Finkelstein, only about a dozen of Shopify’s millions of merchants had ever gone live with the feature. OpenAI itself said the initial version “did not offer the level of flexibility that we aspire to provide,” and confirmed to Modern Retail that checkout was “moving to Apps.” Walmart data cited in coverage of the reversal showed ChatGPT checkout converting roughly three times worse than a click-through to Walmart’s own site, even though ChatGPT reportedly drove about double the new-customer rate Walmart sees from search engines. Purchases now route through dedicated retailer apps inside ChatGPT, i.e. Instacart, Target, DoorDash, Walmart, and others where the retailer, not OpenAI, owns the checkout and the payment relationship. The 4% native fee no longer applies to a live product.
The ACP protocol survived the retreat even though the fee model didn’t. Stripe continued building on it, launching Link Agents (April 29, 2026) to let Stripe-managed consumer wallets approve agent purchases via Shared Payment Tokens, and x402 (February 10, 2026, with Coinbase) for stablecoin settlement on Base, Solana, and Tempo. As of recent, x402 protocol has also introduced batch settlement, a new payment scheme designed for high-frequency, micro low-value transactions performed by AI agents within predefined rules.
Natural and Stripe: Competing for the Rail, Not the Retailer
Natural, a San Francisco startup founded by CEO Kahlil Lalji, closed a $30 million Series A led by Forerunner Ventures’ Kirsten Green on July 20, 2026 — 193 days after the company launched, bringing total funding past $40 million. The company has 17 employees. Its pitch is structural. Traditional card and ACH rails were built for human-authorized payments, and even the most autonomous shopping agent today still hits a human-in-the-loop step at the moment money actually moves. Natural wants agents to hold wallets, pay invoices, and settle with each other without that step, and plans to support both stablecoins and traditional bank rails. It views Stripe, now valued above $150 billion, as its primary competitor, alongside smaller entrants Ralio and Paygentic.
Stripe’s own answer is the Agentic Commerce Protocol stack: ACP for the checkout handshake, Shared Payment Tokens that scope an agent’s access to a specific merchant, amount, and expiration window, and Link Agents for consumer wallet approval. Because Shared Payment Tokens are ultimately mapped to Visa’s or Mastercard’s network tokens, a card-rail ACP transaction still carries standard interchange typically cited at 1.5-3.5% of cart value and standard settlement timing (T+1 to T+2). That’s the specific agentic payments gap Natural and rivals are targeting: interchange and settlement lag baked into the card model, versus a purpose-built agent rail that could settle faster and cheaper, particularly for the sub-dollar, agent-to-agent transactions card rails were never designed to handle.
Who Takes a Cut Today
| Layer | Rate | Status (July 2026) |
| Amazon Buy for Me | 0% commission | Live; beta pricing, no merchant fee disclosed beyond standard product cost |
| OpenAI Instant Checkout native fee | 4% (on top of processing) | Discontinued March 2026; checkout now handled by retailer apps |
| Card network interchange (via ACP/Stripe) | ~1.5-3.5%, “typically ~2%” | Live; applies to any ACP transaction settled over card rails |
| Stripe processing (standalone) | ~2.9% + $0.30 | Live; standard rate, independent of agentic layer |
| Natural | Not yet publicly disclosed | Beta; targeting the authorization/settlement layer rather than a checkout fee |
The current data point is that the only company that tried to charge an explicit, separate fee for agent-initiated checkout, OpenAI pulled it within six months, before it reached meaningful volume. What remains live and monetizing today is the layer nobody markets as an “AI fee” at all: card network interchange, unchanged whether a human or an agent initiates the transaction.
Amazon and OpenAI’s retailer-app model both keep the payment inside existing card-processing economics. Natural and Stripe’s parallel infrastructure bets (Link Agents, x402, and Natural’s own rail) are wagers that a new fee layer becomes viable once agent-to-agent and agent-to-vendor volume, not just agent-to-consumer checkout, starts to move real money. Estimates of that opportunity vary by an order of magnitude depending on definition: eMarketer’s narrowest measure (checkout completed inside an AI platform) puts 2026 US volume at $20.57 billion, while McKinsey’s broadest measure of AI-orchestrated retail revenue reaches $3-5 trillion globally by 2030.
