MPP Session Payments

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Session lifecycle

• open to create the channel and sign the first voucher
• voucher to increase the cumulative paid amount
• topUp to add more deposit
• close to finalize with a last voucher

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1. Install the package

npm install @abstract-foundation/mpp mppx viem zod

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2. Create the client session method

import { abstractSession } from "@abstract-foundation/mpp/client";
import { privateKeyToAccount } from "viem/accounts";

const session = abstractSession({
  account: privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`),
  deposit: "10",
});

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3. Register the server session method

import { Mppx } from "mppx/server";
import { abstract } from "@abstract-foundation/mpp/server";
import { privateKeyToAccount } from "viem/accounts";

const serverAccount = privateKeyToAccount(
  process.env.SERVER_PRIVATE_KEY as `0x${string}`
);

const mpp = Mppx.create({
  methods: [
    abstract.session({
      account: serverAccount,
      recipient: "0xYourWalletAddress",
      amount: "0.001",
      suggestedDeposit: "1",
      unitType: "request",
      testnet: true,
    }),
  ],
  secretKey: process.env.MPP_SECRET_KEY!,
});

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4. Request shape

• amount
• currency
• decimals
• unitType
• optional recipient
• optional channelId
• optional escrowContract
• optional suggestedDeposit
• optional minVoucherDelta

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5. Operational guidance

• pick a suggestedDeposit that supports several expected requests
• settle when the open channel has accumulated enough value or when you need finality
• use topUp instead of reopening when the remaining deposit is too low
• expect cumulative amounts, not independent per-request signatures

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When to use session mode

• your agent will call the same paid API repeatedly
• per-request on-chain overhead is too high
• you want the HTTP flow to stay fast after the initial channel open