z402-storage-sqlite

Storage backend for z402.

Provides:

• Crash-safe payment tracking
• Double-spend resistance
• Idempotent transaction recovery

Install

npm install z402-storage-sqlite

Basic Example

import express from "express";
import { createPaymentContext, type PaymentResult } from "z402/express";
import { initSqliteDb } from "z402-storage-sqlite";
import { Connection, clusterApiUrl } from "@solana/web3.js";

async function main() {
  const app = express();
  const db = initSqliteDb("payments.db"); // creates file locally

  const z402 = await createPaymentContext({
    connection: new Connection(clusterApiUrl("devnet")),
    db,
  });

  // Example paid endpoint
  app.get("/paid", z402.route("DestinationWalletPubkeyHere", "1000000"), (req, res) => {
    console.log(res.locals.payment as PaymentResult)
     res.send({"message": "Payment accepted! here is your paid content.", payment: res.locals.payment });
  });

  app.listen(3000, () => console.log("Example server running on http://localhost:3000"));
}

main();

Persistence (Optional)

To enable crash-proof idempotence:

import { initSqliteDb } from "z402-storage-sqlite";

const z402 = await createPaymentContext({
  connection,
  db: initSqliteDb("./payments.db"),
});