QKart: an AI purchasing agent with a wallet

Turning a plain-language request into a verified purchase, settled in USDG on Robinhood Chain, with the user approving every dollar.

Abstract

Shopping online is a search problem, a comparison problem, and a payment problem, and today the person does all three by hand. QKart collapses them into one loop. A user states what they want. An AI agent reads live retailer listings, confirms price, stock, and delivery, and proposes the single best option with the evidence attached. The user approves with one tap. A dedicated agent wallet pays in USDG on Robinhood Chain, and the order is placed. The agent has no affiliate relationships and ranks only on landed price and fit, so its incentives match the buyer’s. Spending is bounded by rules the user sets and every payment is a public on-chain transfer.

1. The problem

The best price for a given item is rarely on the first page a shopper opens. It is spread across retailers, changes hourly, and depends on coupons, shipping thresholds, and delivery windows that are costly to check by hand. Comparison sites and browser extensions try to close the gap, but they are paid by the merchants they rank, so their answer is biased by design.

Payment adds a second layer of friction. Cards on file, one-time passcodes, and address forms make every purchase a small chore, and they give an automated agent no safe way to act on the user’s behalf. Existing “agentic checkout” products solve this by handing an agent a credit card, which puts the spending limit and the audit trail inside a bank the user does not control.

2. What QKart does

QKart is a conversational purchasing agent. The user types a request in the same words they would use with a friend: the item, the constraints, and the deadline. The agent does four things.

Search. It queries the open web for the exact item, reads candidate product pages, and extracts price, availability, shipping cost, and delivery estimate from what it actually sees.
Compare. It ranks candidates on landed price after shipping and coupons, then on delivery date, seller reputation, and return policy. It discards anything out of stock or outside the user’s constraints.
Propose. It presents one best match as an approval card: the item, the merchant, the price against typical and competing prices, the delivery window, and up to three alternatives.
Pay. On approval the user’s agent wallet transfers USDG on Robinhood Chain and the order enters fulfillment. The transaction hash is attached to the order.

If the request is ambiguous the agent asks one clarifying question before searching. If nothing meets the constraints it says so and offers the closest option. It never invents a price, coupon, or delivery date.

3. Architecture

The system has four components.

Agent. A large language model with live web search and page fetch tools, plus one structured tool that records the proposed offer. The agent runs server-side and streams its progress to the user as it searches.
Wallet service. Generates a unique Robinhood Chain wallet per account, holds its key encrypted at rest, reads USDG and ETH balances, and signs the USDG transfer on approval.
Rules engine. Enforces the user’s ask-above threshold, rolling 24-hour limit, and auto-buy setting before any transfer is signed. Rules are checked at approval time, not at proposal time, so a stale offer cannot bypass them.
Fulfillment layer. Receives paid orders and places them with the retailer through a settlement wallet, which funds the purchase with the retailer. Order state is tracked from awaiting approval through paid, fulfilled, or failed.

4. Agent wallets and spending rules

Every account gets its own wallet on Robinhood Chain at sign-up. The user funds it by sending USDG, plus a small amount of ETH for network fees, to the address shown in the app. Funds remain in that wallet until an approved purchase moves them. The user can withdraw at any time.

Three rules bound what the agent can do with the balance.

Ask-me threshold. Any order above this amount always requires an explicit approval.
Daily limit. A rolling 24-hour cap on total approved spend. Orders that would exceed it are rejected before payment.
Auto-buy. Off by default. When on, orders under the threshold and within the daily limit can complete without a tap, for everyday reorders.

5. Settlement on Robinhood Chain

QKart settles in USDG, the Global Dollar stablecoin issued by Paxos and native to Robinhood Chain. Robinhood Chain is an Ethereum layer 2 built on Arbitrum technology with sub-second confirmation and fees measured in fractions of a cent, which makes it practical to settle a $68 bouquet as an on-chain transfer.

On approval the agent wallet sends exactly the order amount in USDG to a settlement wallet operated by QKart. The transaction hash is stored on the order and linked from the approval card. There is no card on file, no chargeback window, and no balance held anywhere the user cannot inspect on a public explorer.

6. Fulfillment

Retailers do not accept USDG at checkout, so the settlement wallet funds the actual purchase. Paid orders are placed with the merchant by QKart from the settlement wallet’s funds, shipping to the address the user set. The order updates as the purchase is placed, shipped, and delivered. The buyer never provides a card at any point.

If a purchase cannot be completed, for example because stock sold out between proposal and approval, the order is marked failed and the USDG is returned to the user’s agent wallet.

7. Security and custody

Agent wallet keys are generated server-side and stored only in encrypted form. They are decrypted in memory for the duration of a single signed transfer.
The agent that searches and proposes never touches keys. Only the approval endpoint, gated by the user’s session and the rules engine, can sign.
Every purchase requires a user action unless the user has explicitly enabled auto-buy under a threshold they chose.
All settlement is visible on Robinhood Chain’s public explorer. There are no internal balances to reconcile.
Sessions are encrypted, HTTP-only cookies. Passwords are stored as salted hashes.

8. Economics

QKart charges no subscription and adds no markup to the item price. Revenue is a small service fee on completed orders, shown on the approval card before the user pays, and a share of any merchant-side savings the agent secures through coupons or price matching. The agent never receives affiliate commissions, so its ranking is not for sale.

9. Roadmap

Now: physical goods from major retailers, single-item and bundle orders, USDG settlement on Robinhood Chain.
Next: travel, including flights, hotels, and ground transport, with date-aware search and fare tracking.
Then: food and grocery delivery, tickets, reservations, and appointments.
Ongoing: price-drop watches that re-check an item and buy when it hits a target, and shared household wallets with per-member rules.

10. Risks and disclosures

QKart is a purchasing tool, not a bank, broker, or custodian of securities. It does not offer investment products.
USDG is issued by Paxos, not by QKart. Its value depends on the issuer’s reserves and redemption terms.
Prices and availability come from live retailer pages and can change between proposal and approval. The agent re-checks before paying, but a listing can still change after that point.
Agent wallet keys are held by the service in encrypted form. Users should keep only what they intend to spend in the agent wallet.
Robinhood Chain is operated by Robinhood. QKart is an independent application built on it and is not affiliated with or endorsed by Robinhood.

Glossary

Agent wallet: The Robinhood Chain wallet created for each account, funded with USDG and controlled by the user’s rules.
Landed price: The total cost of an item after shipping, coupons, and taxes.
Robinhood Chain: An Ethereum layer 2 network built by Robinhood on Arbitrum technology, chain ID 4663.
Settlement wallet: The QKart wallet that receives approved USDG payments and funds fulfillment.
USDG: Global Dollar, a US dollar stablecoin issued by Paxos and used natively on Robinhood Chain.