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Use with Agents

Let your agent pay for services autonomously through persistent channels.

Install

npm install @valeo/amp-client @solana/web3.js

Basic usage

AMPClient.fetch() is a drop-in replacement for native fetch(). It handles discovery, channel opening, and credential signing automatically.

import { AMPClient } from "@valeo/amp-client"
import { Keypair, Connection } from "@solana/web3.js"
 
const amp = new AMPClient({
  wallet: agentKeypair,
  connection: new Connection("https://api.mainnet-beta.solana.com"),
  budget: 10.00,    // $10 USDC total budget
  token: "USDC",
})
 
// First call: discovers pricing, opens channel, then fetches
const res = await amp.fetch("https://api.example.com/v1/data", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ query: "What is AMP?" }),
})
 
console.log(await res.json())
console.log("Balance:", res.ampBalance)  // remaining channel balance
 
// Subsequent calls reuse the open channel — zero on-chain cost
for (let i = 0; i < 100; i++) {
  await amp.fetch("https://api.example.com/v1/data")
}
 
// Close all channels when done — remaining budget refunded
await amp.closeAll()

What happens under the hood

  1. Discovery — on first call to a new host, the client fetches /.well-known/amp.json to learn pricing and the server's pubkey.
  2. Channel open — the client submits one Solana transaction to open a channel with a deposit.
  3. Request signing — every request includes three headers:
    • AMP-Channel — the channel PDA address
    • AMP-Seq — a monotonically increasing sequence number
    • AMP-Sig — Ed25519 signature of the sequence number
  4. Retry — if a 402 is returned (pricing changed), the client re-discovers and opens a new channel automatically.
  5. Close — closeAll() closes every open channel and refunds remaining balances.

Explicit channel management

If you want more control, open and close channels directly:

const channel = await amp.openChannel({
  recipient: serverPubkey,
  deposit: 5.00,
  settleInterval: 3600,
})
 
await amp.topUp(channel, 2.00)   // add more funds
await amp.close(channel)          // close and refund

Check remaining budget

const remaining = amp.getRemainingBudget()  // in human units
console.log(`${remaining} USDC remaining`)

Next steps