# Why Radius for Agent Payments

**Radius is a settlement layer — the infrastructure where stablecoin micropayments reach finality.** Purpose-built for machine-to-machine payments at the scale of API calls on the open internet.

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## The Problem

The internet is shifting from subscription-based access to pay-per-use micropayments between autonomous agents. AI agents are already paying for API calls, data feeds, compute, and inference on a per-request basis — and the volume is growing fast.

Existing payment infrastructure wasn't built for this.

**Conventional payment rails** — Visa, Mastercard, ACH, Stripe's card processing — assume human-initiated, multi-dollar transactions. Their fee structures include fixed per-transaction costs ($0.10-0.30+) that make sub-dollar payments economically impossible. On a $0.01 agent transaction, a standard credit card interchange fee of 1.80% + $0.10 produces a total fee of $0.10 — **1,000x the transaction value**. This isn't a feature gap. It's structural.

**General-purpose blockchains** improve on cost but hit throughput ceilings. Base processes ~2,000 TPS. Solana handles ~5,000 TPS in practice. These networks were designed for DeFi and consumer crypto, not for settlement at the scale of internet API traffic.

**Purpose-built payment chains** like Tempo (Stripe/Paradigm) target 100,000 TPS — a significant improvement. But agent-scale micropayments will demand more. Cloudflare alone processes ~81 million HTTP requests per second. If even 0.1% of global API traffic becomes monetized with per-request payments, you need 500,000-1,000,000 TPS of settlement capacity. At 1%, you need tens of millions.

The settlement layer for the agentic internet needs to look more like Cloudflare than Visa.

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## What Radius Is

**Radius is Layer 3 settlement infrastructure** in the agentic payment stack. When an AI agent pays for an API call using x402, that payment must settle somewhere. Radius provides the high-throughput, low-latency, predictable-cost infrastructure where those transactions reach finality.

**What Radius is not:**
- Not a wallet (that's Layer 5 — Skyfire, Nekuda, Coinbase AgentKit)
- Not a protocol (that's Layer 4 — x402, AP2, ACP)
- Not a general-purpose blockchain (that's Layer 1 — Ethereum, Solana)

**The architecture:** Radius is a massively scalable EVM transaction processor built on a generalized database architecture optimized for high-volume, low-latency state updates. It uses parallel transaction processing (PArSEC — Parallel Architecture for Serializable Execution) to achieve linear scaling: throughput increases proportionally as compute resources are added. The architecture separates execution from consensus and employs geographic partitioning to execute non-conflicting transactions simultaneously while maintaining state consistency.

| Metric | Radius |
|--------|--------|
| **Throughput** | 2.8M+ TPS tested, linearly scalable |
| **Finality** | ~500ms |
| **Cost per transaction** | ~$0.00001 |
| **Cost per million txns** | ~$10 |
| **EVM compatibility** | Full — Solidity, Foundry, viem, ethers.js |
| **Native token** | None — stablecoin-compatible, asset-agnostic |
| **Architecture** | Purpose-built for agent micropayments |

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## How Radius Compares

### Conventional Rails

| Network | Max TPS | Cost per Txn | Settlement | Micropayment Viable? |
|---------|---------|-------------|------------|---------------------|
| Visa | ~65,000 | 1.5-3.5% + $0.10-0.30 | T+1 to T+2 | No — fixed fees exceed transaction value below ~$5 |
| Mastercard | ~20,000 | 1.1-3.15% + $0.10-0.30 | T+1 to T+2 | No — same fixed-fee problem |
| ACH | Batch | $0.20-1.50 flat | Same-day to T+2 | No — batch-only, $0.20 minimum |
| Stripe (cards) | N/A | 2.9% + $0.30 | T+2 | No — $0.30 floor |

### Blockchain-Based Settlement

| Network | TPS | Cost per Txn | Cost per Million | Finality | Purpose-Built for Agents |
|---------|-----|-------------|-----------------|----------|-------------------------|
| **Radius** | **2.8M+ tested** | **~$0.00001** | **~$10** | **~500ms** | **✓** |
| Base | ~2,000 | ~$0.001-0.01 | ~$1,000-10,000 | ~2s | ✗ (general-purpose L2) |
| Solana | ~5,000 | ~$0.00025 | ~$250 | ~400ms | ✗ (general-purpose L1) |
| Arbitrum | ~2,000 | ~$0.0001-0.001 | ~$100-1,000 | ~13s (L1 finality) | ✗ (general-purpose L2) |
| Tempo | 100K target | TBD | TBD | Sub-sec target | ✓ (merchant payments, payroll) |
| Kite AI | Not disclosed | Low (subsidized) | Not disclosed | ~1s | ✓ (agent commerce) |

**The scaling threshold:** Below 10K TPS, general-purpose L2s like Base work fine. Between 10K-100K TPS, you start hitting constraints. Above 100K TPS, purpose-built infrastructure like Radius becomes necessary for guaranteed performance.

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## What You Have to Believe

The right settlement layer depends on your assumptions about how big agent-to-agent commerce becomes:

**If agent micropayments stay below ~2,000 TPS**, Base works. But x402 already hit 600,000+ daily transactions on Base by late 2025. This threshold is already being tested.

**If agent micropayments stay below ~100,000 TPS**, Tempo works. This is plausible for the next 1-2 years of early adoption. Tempo is well-positioned for merchant stablecoin payments, payroll, and enterprise settlement at this scale.

**If even a fraction of global API traffic becomes monetized per-request**, you need Radius. The math:

| API Traffic Monetized | Settlement TPS Needed | Which Network Handles It |
|----------------------|----------------------|-------------------------|
| Current x402 volume | ~7 TPS avg (600K/day) | Base, Solana, any |
| 0.01% of global API traffic | ~50,000 TPS | Tempo (at its ceiling) |
| 0.1% of global API traffic | ~500,000 TPS | Radius |
| 1% of global API traffic | ~5,000,000 TPS | Radius (with linear scaling) |
| 10% of global API traffic | ~50,000,000 TPS | Radius (with continued scaling) |

Radius is designed for the rows where other infrastructure runs out of capacity.

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## Why No Native Token Matters

Most blockchain networks fund their operations through native tokens — ETH, SOL, or network-specific gas tokens. This creates misaligned incentives:

- **Gas auctions** cause transaction costs to spike unpredictably during high demand
- **Validator economics** are tied to token price appreciation, not network utility
- **Users must acquire and manage a volatile asset** just to pay for transactions
- **Token speculation** can distort network behavior and governance

**Radius has no native token.** Transaction fees are paid in stablecoins (USDC, PYUSD, or other fiat-pegged tokens). Fees are ~$0.00001 per transaction, paid in the same stablecoin being transferred. Network economics are aligned with users and usage, not token holders and speculation.

For enterprises and developers building payment infrastructure, this means:
- Predictable costs that don't spike with network congestion
- No exposure to crypto asset volatility
- No need to acquire, hold, or manage a gas token
- No incentive conflicts between network operators and users

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## Migration Path from Base

If you're settling x402 payments on Base today, moving to Radius is a configuration change, not a code rewrite.

**What stays the same:**
- ✓ Your x402 protocol integration
- ✓ Your API code and endpoints
- ✓ Agent wallet compatibility (same address format)
- ✓ Stablecoin (USDC)
- ✓ EVM contracts (deploy without modification)

**What changes:**
- Settlement RPC endpoint (Base → Radius)
- x402 facilitator endpoint (Coinbase CDP → Radius facilitator)
- USDC contract address (Base USDC → Radius USDC)

**When you need to migrate:** When your peak throughput exceeds 10K TPS, when you require guaranteed sub-second finality, or when cost predictability is critical to your unit economics.

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## Who Built This

Radius is a Boston-based team with a decade of experience building financial infrastructure at the institutions that set standards:

- **Federal Reserve** — central bank payment systems
- **MIT Digital Currency Initiative** — CBDC research
- **Circle** — USDC co-creators
- **Zcash** — co-founders, zero-knowledge cryptography

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## Get Started

Radius testnet is live. Deploy your first contract, make your first transaction, or integrate with x402 for agent micropayments.

- [Quick Start: First Payment]() — zero to first transaction in 5 minutes
- [Network Configuration]() — connect to testnet
- [Smart Contract Deployment]() — deploy Solidity with Foundry, no modifications
- [Settlement Layer Comparison](https://radiustech.xyz/llms/settlement-comparison) — detailed comparison with all alternatives
- [The Agentic Payment Stack](https://radiustech.xyz/llms/agentic-payment-stack) — seven-layer architecture showing where Radius fits