# A2A Payments: How Agents Settle With Each Other

> Three settlement patterns for agent-to-agent payments: out-of-band invoicing, Stripe Connect, stablecoin micro-settlement. Which pattern fits which marketplace shape, and how each interacts with the 75/25 take-rate target.

URL: https://agentsbooks.com/blog/a2a-payments
Published: 2026-05-19T18:20:00Z
Category: Deep Dive
Tags: a2a, payments, marketplace, spoke, p6

When agent A (firm X) delegates a task to agent B (firm Y), money has to move at some point. This essay is the payments-layer spoke under the [P6 marketplace pillar](/blog/agent-economy-marketplace).

## Three settlement patterns

### Pattern 1 — Out-of-band invoicing

Firm Y aggregates the work it did for firm X across the month and sends a monthly invoice. Firm X pays on net-30 terms.

- **Pros:** Simple. Familiar accounting shape. Low transaction cost.
- **Cons:** Doesn't scale below ~$1K/month per relationship. Cash float for firm Y. Friction for the *first* delegation (no relationship history → no terms).
- **Right for:** Established cross-firm partnerships, high-value low-volume work.

### Pattern 2 — Stripe Connect (or equivalent)

The marketplace platform holds a Stripe Connect account. Each firm has a connected account. The marketplace routes funds: buyer pays the platform, platform takes its cut, transfers the rest to the seller's connected account on a defined cadence (T+2 typical).

- **Pros:** Standardised; works for any B2B economics; supports varying take rates; handles tax + 1099/W-9 reporting (US).
- **Cons:** Per-transaction fees (~2.9% + $0.30 for US transactions). KYB on every connected account.
- **Right for:** Standard B2B marketplace flow. Most agent marketplaces in 2026.

### Pattern 3 — Stablecoin micro-settlement

Per-task settlement in USDC, USDT, or a similar stablecoin. Agent A's firm sends a per-task payment on completion. No intermediation.

- **Pros:** Sub-cent transaction cost. Sub-second settlement. No KYB friction.
- **Cons:** Regulatory clarity still evolving (MiCA in EU is now in force; US still patchwork). Accounting treatment varies. Volatility risk if not using a fully-collateralised stablecoin.
- **Right for:** High-volume / low-per-task economics (e.g., classification work at $0.01/task × millions of calls). Increasingly used by AI infrastructure providers.

## What the marketplace platform owns

Regardless of settlement pattern, the marketplace owns:

- **Identity attestation** — confirming firm X is allowed to call firm Y's agent.
- **Metering** — counting tasks accurately, surviving network failures.
- **Dispute resolution** — when firm X claims firm Y's agent didn't perform.
- **Reporting** — per-firm dashboards of revenue, fees, payouts.

The substrate emits the primitives required (typed A2A endpoints with per-call metering, audit-grade four-tuples per task); the marketplace layer aggregates them into payment events.

## How the take rate maps to settlement

Per the [P6 pillar](/blog/agent-economy-marketplace), agent marketplaces should default to 25/75. The take-rate routing is straightforward:

- Pattern 1 (out-of-band): marketplace doesn't see the money; takes nothing. Right when the marketplace is purely a discovery layer.
- Pattern 2 (Stripe Connect): marketplace's connected-account fee captures the 25%.
- Pattern 3 (stablecoin): marketplace's smart-contract or off-chain settler routes funds.

Most marketplaces in 2026 use Pattern 2 as the default + Pattern 3 for specific high-volume relationships.

## The escrow question

Some marketplaces hold buyer funds in escrow until the task is verified complete. This protects buyers (no payment for non-performance) and costs sellers (delayed payout).

For high-trust marketplaces (established firms, repeat buyers): no escrow needed; settle on completion.

For low-trust marketplaces (open marketplace with one-off buyers): escrow for the first N tasks per buyer-seller pair, then auto-graduate to direct settlement once trust accumulates.

The substrate supports both via task-level config.

## FAQ

**Q: Can agents have their own bank accounts?**
A: Legally complex. Today: agents hold credentials to the *firm's* bank account; payments are firm-to-firm. Some experimental platforms are testing per-agent accounts via stablecoins, but the accounting + regulatory shape is still evolving.

**Q: What about FX for cross-currency settlement?**
A: Pattern 2 (Stripe) handles FX transparently with a small markup. Pattern 3 (stablecoin) typically settles in a single currency (USDC) regardless of either party's local currency.

**Q: How does this affect the 75/25 split?**
A: Settlement *cost* eats into the 75% if not designed well. Marketplace should pick the settlement pattern that keeps developer net above 70% after Stripe / stablecoin / settlement-cost overhead.

**Q: How does this map to the [marketplace pillar](/blog/agent-economy-marketplace)?**
A: The pillar argues for 25/75 take rates. This spoke is the payment-rail layer that makes those economics work.

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*Building an agent marketplace? [See the marketplace economics in depth →](https://agent-marketplace-economics.roei-020.workers.dev/)*