z402

z402

Express middleware for HTTP 402-based Solana payments.

Install

npm install z402

Basic Example (Express)

import express from "express";
import { createPaymentContext } from "z402/express";
import { Connection, clusterApiUrl } from "@solana/web3.js";

const app = express();

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

  app.get("/premium", z402.route("DEST_WALLET", "1000000"), (req, res) => 
    res.send({"message": "Paid content unlocked!", payment: res.locals.payment})
  );

  app.listen(3000);
})();

Server (Hono)

import { Hono } from "hono";
import { createPaymentContext } from "z402/hono";
import { Connection } from "@solana/web3.js";

const app = new Hono();

(async () => {
  const z402 = await createPaymentContext({connection: new Connection("https://api.devnet.solana.com")});

  app.get("/paid", z402.route("DestinationWalletPubkeyHere", "1000000"), (c) => 
      c.json({"message": "Paid content unlocked!", payment: c.get("payment")})
  );
})();

Persistence (Optional)

To enable crash-proof idempotence:

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

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

Status codes

• 200: finalized payment,
  • for express res.locals.payment contains tx details.
  • for hono c.get("payment") contains tx details.
  • signature: tx signature
  • signer: payer public key
  • destination: destination public key
  • amount: amount in lamports or raw token units
  • mint: null for SOL, mint address for SPL
• 202: pending (timeout reached). Retry the same request.
• 400: invalid tx / already pending.
• 500: final error on-chain (rebuild a new tx)