Introduction

The Quantoz agentic stack lets AI agents pay with regulated European money over two settlement rails:

EURO — a MiCA-regulated euro e-money token in Quantoz managed accounts. Off-chain, instant, zero fees, no crypto wallet needed.
EURQ / USDQ — EUR and USD stablecoins issued by Quantoz, live on Algorand, Ethereum and Polygon. Self-custody, on-chain settlement.

Both plug into the same two agent-facing interfaces: MCP tools for conversational agents and the x402 protocol for machine-to-machine payments. This page is the map; every other page is a zoom-in.

The problem

AI agents can already decide to pay — they calculate who owes what, find the cheapest flight, pick the right API. But most cannot execute: they stop at a paywall and hand back a URL. The rails that could serve them are split in two: bank rails that machines can’t operate, and crypto rails that mainstream European users and enterprises can’t adopt. This stack bridges both sides with regulated money in machine-usable form.

Two kinds of money

	EURO	EURQ	USDQ
What it is	E-money token (EUR 1:1)	EUR stablecoin	USD stablecoin
Lives on	Quantoz ledger (off-chain)	Algorand · Ethereum · Polygon	Algorand · Ethereum · Polygon
Custody	Quantoz managed accounts	Self-custody wallets	Self-custody wallets
Settlement	Instant	~5 sec – 2 min	~5 sec – 2 min
Fees / gas for the payer	None	None (facilitator sponsors fees/gas)	None (facilitator sponsors fees/gas)
Best for	Consumer/agent wallets, instant micro-payments, spending controls	On-chain settlement, DeFi composability	USD-denominated on-chain payments

All three are issued by Quantoz Payments BV under an EU e-money licence (MiCA). The two rails are deliberately separate: EURO moves only between Quantoz accounts, and EURQ/USDQ move only on-chain — a EURO account cannot pay a blockchain address or vice versa. Moving value between the rails is a Quantoz issuance/redemption step, not a payment.

Three ways to integrate

Rail	Money	Agent needs	Merchant needs	Start here
MCP tools — 37 typed tools for conversational agents (Claude, Cursor, OpenAI Agents SDK)	EURO	Quantoz account + API key	Quantoz account (to be paid)	Quickstart
x402 `euro` scheme — per-request HTTP payments, off-chain	EURO	Quantoz account	Quantoz account + 2 API calls	x402 overview
x402 `exact` scheme — per-request HTTP payments, on-chain	EURQ / USDQ	Whitelisted Algorand wallet or EVM wallet holding the tokens	Algorand address and/or EVM address	Merchant guide

How it fits together

  AI AGENT                    MERCHANT                    SETTLEMENT
┌───────────────┐   1. GET resource   ┌──────────────┐
│ MCP client     │ ──────────────────▶ │ any HTTP     │
│ (Claude, …)    │   2. 402 + accepts  │ endpoint     │
│                │ ◀────────────────── │              │
│ x402 client    │   [euro | exact ×3] │ verifies via │
│ (x402-quantoz- │   3. pay + retry    │ facilitator  │
│  euro npm)     │ ──────────────────▶ │              │──▶ euro   → Quantoz ledger (instant)
│                │   4. 200 OK         │              │──▶ exact  → Algorand  (fee-sponsored)
│ EVM / Algorand │ ◀────────────────── │              │──▶ exact  → Ethereum / Polygon
│ wallet         │                     │              │            (EIP-2612 permit, gasless)
└───────────────┘                     └──────────────┘

The merchant’s 402 response lists every payment option it accepts (up to four: EURO plus three networks). The agent pays with whichever it can satisfy — the withEurPayment() wrapper picks automatically. Facilitators do the heavy lifting: the EURO facilitator creates and verifies payment requests with replay protection; the on-chain facilitator (x402algo.ai.quantozpay.com) validates and settles transactions, sponsoring all network fees so agents never hold ALGO, ETH or POL.

Which setup do I need?

You are building…	You need	Guide
A conversational agent that pays in euros	EURO account + API key, MCP config	Setup part 1 → Quickstart
An autonomous agent that pays x402 APIs	EURO account + the `x402-quantoz-euro` package (covers `euro`, plus EVM if you add a wallet)	Agent guide
An agent that pays from self-custody crypto	EVM wallet holding EURQ/USDQ, and/or a whitelisted Algorand wallet	Setup part 2
A merchant accepting agent payments	EURO account (+ optional Algorand/EVM receiving addresses for on-chain)	Merchant guide

What agents can do

Split a bill and pay everyone in one instruction
Pay a freelancer on delivery
Subscribe to a data API by the request
Automatically pay x402-protected websites and APIs — in EURO or on-chain
Accept payment via QR, payment link, or their own 402 responses

Next steps

→ Set up accounts & wallets — EURO account, and optionally stablecoin wallets. → Quickstart — a working agent payment in under 5 minutes. → x402 overview — the payment schemes in detail.