Show HN: CartAI – Checkout API for AI agents and apps

CartAI — The AI Agent That Handles Checkout

Live · Launching on Product Hunt soon

The AI agent that handles checkout.

One API to deploy a specialized agent that navigates any web property and completes the transaction — checkout, subscription sign-up, invoice payment, order submission, anywhere a transaction has to happen. Automate it. Embed it, or enable it on surfaces that never had it. Composable. Reliable. Developer-first.

Start buildingRead the docs

// POST https://api.cartai.ai/checkout const response = await fetch("https://api.cartai.ai/checkout", { method: "POST", headers: { "Content-Type": "application/json", "Authorization": Bearer ${process.env.CARTAI_KEY}, }, body: JSON.stringify({ customer: { email: "[email protected]", name: "Jane Doe", }, tasks: [{ target: "bestbuy.com/site/sony-wh-1000xm5/6505727.p", variant: { color: "black" }, shipping: { profile: "./buyer.json" }, payment: { profile: "./card.json" }, }], options: { sandbox: true }, }), });

const { taskId, status } = await response.json(); // → taskId: "task_abc123", status: "queued" // Execution runs async — listen via webhook for completion.// Webhook listener — subscription lifecycle events import express from "express";

const app = express(); app.use(express.json());

app.post("/webhooks/cartai", (req, res) => { const { event, data } = req.body;

switch (event) { case "STARTED": notify_customer(data.customerId); break; case "COMPLETED": send_post_purchase_flow(data.customerId); break; case "FAILED": do_retry(data.customerId, data.executionId); break; }

res.sendStatus(200); });

app.listen(3000);

Surfaces supported

Any web property.

If a workflow has to navigate it, CartAI can transact through it.

All e-commerce checkouts

Custom carts

Intranet portals

Vendor portals

Login-gated workflows

The category

A specialized layer at a specialized intersection.

Browser automation and agentic payments are both vast, important categories. Neither is built specifically for the workflows where a transaction has to actually clear. CartAI is.

Browser automation

Tools that navigate the open web

General-purpose web automation. Built to handle any task — research, scraping, form-filling, data extraction, navigation across the open web.

Scope: the universe of browser-based tasks. Transactional reliability is one slice of a much broader remit.

Programmable transactions, made reliable

AI-driven browser execution and payment infrastructure fused into a single primitive. Built specifically for workflows where a transaction has to clear — and not built for workflows where one doesn't.

Scope: specialized by design. The constraint is the moat.

Agentic payments

Authentication and payment rails for agents

The identity, trust, and rails layer that lets agents transact safely on behalf of users — KYA, signed credentials, agent-issued payment instruments.

Scope: the rails that make agentic payments trustable. Pairs with an execution layer that can navigate to the payment.

Both adjacent categories solve real problems. CartAI solves the one between them: the transaction has to clear. A specialist primitive built for that single, non-negotiable outcome.

The moat

Anyone can navigate. Few can clear a transaction.

The hard part isn't the click. It's everything between the click and the confirmation. We engineered three pieces into the primitive — the ones that have to be right or the transaction silently fails.

01

Composable workflows

Built for every shape a transaction can take.

Every flow has its own shape — some need shipping, some don't; some need 3DS, some don't; some need login, some don't. CartAI workflows assemble the steps your specific situation requires, while always landing somewhere transactional.

Composable step primitives

Conditional branching

Idempotent, retry-safe

02

PCI-compliant payment stack

Card intake, vaulting, and agentic protocols — built right.

Full PCI-compliant credit card intake and vaulting, integrated with the agentic payment protocols the next generation of transactions will run on.

PCI DSS compliant intake

Tokenized card vaulting

Agentic protocol support

03

Cooperative bot-mitigation

Cleared, not flagged.

We don't evade Cloudflare, Human, or Fingerprint — we cooperate with them via Web Bot Auth, Skyfire KYA, and signed agent identity. Transactions clear cleanly through the same trust infrastructure that protects the world's largest merchants.

Web Bot Auth signed identity

Skyfire KYA integration

Cloudflare / Human / Fingerprint

Proof, not slides

Transactions that cleared.

Below: workflows that ended in confirmed orders. Same API, same SDK, same primitive. Recorded against production merchant surfaces — not staged, not simulated.

Cleared

BestBuyElectronics

Cleared

NeweggElectronics

Cleared

JomashopLuxury

Cleared

UltaBeauty

The platform

One primitive. Four products.

Checkout is the hard part we solve, and the wedge everything else sits on. Four products cover the full transaction lifecycle around it: find the product, clear the order, move the money, share the upside.

01

Catalog

Search products across merchants, pull variants and live pricing, and return checkout estimates before any cart exists.

Search · Details · Estimates

Explore Catalog

Core

Checkouts

Clear the order on the live merchant surface, then track it to confirmation with normalized orders and webhooks.

Checkout API · Orders · Webhooks

Explore Checkouts

03

Payments

Hosted payment sessions via Visa Intelligent Commerce and Mastercard Agent Pay. PCI scope stays off your stack.

Payment Sessions · PCI out of scope

Explore Payments

04

Monetization

When an agent buys through your surface, you still earn. Affiliate commissions with attribution built in.

Commissions · Attribution

Explore Monetization

Signed, verified, allowed. CartAI operates inside the trust infrastructure, not around it.

KYA

+ more coming online

Two ways to ship

An API to build on. A cart to drop in.

Devs who want full control wire CartAI into their workflow directly. Surfaces that need a turnkey checkout drop in our hosted cart and ship in an afternoon. Same primitive underneath either way.

Product · API

CartAI API

The full programmable-transaction primitive. Payments, Orders, Workflows. Compose any flow that ends in a transaction.

Webhooks for every state transition

Idempotent, retry-safe by design

Production environments

Product · Hosted Cart

CartAI Hosted Cart

Drop-in checkout for surfaces that never had one. Variant selection, addresses, payment, confirmation — embed it in one line. Same primitive underneath; the transaction still clears the same way.

Drop-in component or iframe

Variants, addresses, payment built in

White-label theming

Powered by the same API underneath

Three modes

Automate, embed, or enable.

Every CartAI use case maps to one of three modes — replace a manual transactional process, embed transactions into a new application, or add transactions to a surface that never had them.

01 — Automate

Existing transactional processes.

Replace manual checkout, billing, and procurement flows with reliable, programmable execution.

E-commerce checkout

Products, variants, addresses, payment — across retail, electronics, beauty, luxury.

Affiliate & loyalty

Eliminate redirect drop-off. Preserve attribution. Lift conversion.

Subscriptions & renewals

Sign-up, plan changes, cancellations across any subscription portal.

Invoice & bill payment

Vendor portals, healthcare bills, utility accounts — log in, select, pay, confirm.

Procurement & PO submission

B2B vendor portals, supply orders. Submit against an invoice number — payment optional.

02 — Embed

Transactions into new applications.

Build apps where transactions are part of the experience — agents, copilots, vertical AI tools, marketplaces.

AI-native commerce surfaces

Shopping copilots, virtual assistants — give them the ability to actually transact.

Vertical AI apps

Domain-specific agents — gift finders, recipe-to-cart, virtual closets, travel planners.

Marketplaces & aggregators

Brand-owned checkout in discovery surfaces — no third-party redirect required.

Digital products

Software licenses, courses, content access. No shipping step required.

03 — Enable

On surfaces that never had them.

Add transactions where they didn't exist before — editorial pages, content sites, recommendation feeds, creator surfaces.

Publishers & editorial

Make any editorial surface shoppable. Direct checkout, no redirects.

Influencer platforms

Embed checkout into creator surfaces — preserve creator attribution.

Content & media properties

Recommendation feeds, gift guides, reviews — convert intent in place.

Recommendation engines

Add transactional capability to discovery and curation surfaces.

Workflows have been built across:

Retail & E-commerceHealthcareB2B SaaSTelecomTravel & HospitalityFinancial ServicesMedia & PublishingAI-native AppsEducationNonprofit & Donations

Vertical coverage reflects workflows we've built or piloted. Productized solutions vary by sector — talk to us about yours.

Programmable transactions, in production today.

Get an API key, hit the platform, watch your first workflow clear today.

Get API keyTalk to us