Circle Nanopayments
TestnetCircle Nanopayments — Circle (USDC)
Overview
Circle Nanopayments is Circle's infrastructure for sub-cent USDC transactions optimized for AI agent micropayments. It uses payment channels and batched settlement to enable transactions as small as fractions of a cent — making it economical for AI agents to pay per-token, per-byte, or per-millisecond for services.
How It Works
Traditional on-chain transactions have a floor cost (gas fees) that makes sub-cent payments impractical. Circle Nanopayments solves this with payment channels: the consumer opens a channel by depositing USDC into a smart contract, then sends signed payment authorizations (off-chain) for each micro-transaction. The service provider accumulates these authorizations and settles on-chain periodically.
This amortizes gas costs across thousands of micro-transactions, making per-token pricing (e.g., $0.001 per token) economically viable. Channels can be topped up, and settlement frequency is configurable — from real-time to daily batches.
Circle provides the USDC infrastructure, smart contract templates, and SDKs for both the payer and payee. The protocol is designed specifically for high-frequency, low-value transactions like AI inference, data streaming, and API calls.
How SettleGrid Integrates
SettleGrid supports Circle Nanopayments as a payment method for consumers who prefer USDC micropayments. When a consumer opens a nanopayment channel, SettleGrid manages the channel state, accumulates payment authorizations per tool call, and settles on-chain at configurable intervals. Developers receive payouts in fiat or USDC, and the entire nanopayment flow is abstracted behind the same sg.wrap() interface.
Key Specs
| Protocol | Circle Nanopayments — Circle Nanopayments |
| Backer | Circle (USDC) |
| Detection Header | X-Circle-Channel / Authorization: NANO <channel-id> |
| Identity Type | usdc-channel |
| Payment Type | nanopayment-channel (USDC) |
| Status | Testnet |
Code Example
Here is how a developer's tool works with Circle Nanopayments via SettleGrid:
import { settlegrid } from '@settlegrid/mcp'
const sg = settlegrid.init({
toolSlug: 'llm-proxy',
pricing: {
// Sub-cent pricing enabled by nanopayments
defaultCostCents: 0.1, // $0.001 per call
methods: {
'tokenize': { costCents: 0.01 },
'embed': { costCents: 0.5 },
'generate': { costCents: 2 },
},
},
// Circle Nanopayment channels are managed automatically
})
const embed = sg.wrap(async (args: { text: string }) => {
const embedding = await generateEmbedding(args.text)
return { content: [{ type: 'text', text: JSON.stringify(embedding) }] }
}, { method: 'embed' })Start monetizing with SettleGrid
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