Stream402 SDK

A TypeScript SDK for integrating Stream402 payment protocol into your applications. Stream402 enables monetization of digital content using Solana payments via the x402 protocol.

Installation

npm install @stream402/sdk

Quick Start

1. Discover an Asset

Check if an asset requires payment:

import { discover } from "@stream402/sdk";

const result = await discover("https://example.com/api/asset/123");

if (result.type === "free") {
  // Asset is free, use the URL directly
  console.log("Free asset:", result.url);
} else {
  // Payment required
  console.log("Payment required:", result.challenge);
  console.log("Amount:", result.challenge.amount, result.challenge.currency);
}

2. Pay and Fetch

Complete payment flow and get access to the resource:

import { payAndFetch } from "@stream402/sdk";
import { useWallet } from "@solana/wallet-adapter-react";

function MyComponent() {
  const wallet = useWallet();

  const handlePayAndFetch = async () => {
    try {
      const result = await payAndFetch(
        "https://example.com/api/asset/123",
        wallet
      );

      console.log("Download URL:", result.downloadUrl);
      console.log("Expires at:", new Date(result.expiresAt));

      // Use the download URL to access the resource
      window.open(result.downloadUrl, "_blank");
    } catch (error) {
      console.error("Payment failed:", error);
    }
  };

  return <button onClick={handlePayAndFetch}>Pay & Download</button>;
}

3. Upload Asset

Upload an asset as a content provider:

import { uploadAsset } from "@stream402/sdk";
import { useWallet } from "@solana/wallet-adapter-react";

function UploadComponent() {
  const wallet = useWallet();

  const handleUpload = async (file: File) => {
    try {
      const result = await uploadAsset(
        file,
        {
          title: "My Image",
          price: 0.01, // USDC
          tags: ["nature", "landscape"],
          description: "A beautiful landscape image",
        },
        wallet
      );

      console.log("Asset uploaded:", result.assetId);
      console.log("Asset URL:", result.url);
    } catch (error) {
      console.error("Upload failed:", error);
    }
  };

  return (
    <input
      type="file"
      onChange={(e) => {
        const file = e.target.files?.[0];
        if (file) handleUpload(file);
      }}
    />
  );
}

API Reference

discover(assetUrl: string): Promise<DiscoverResult>

Fetches an asset URL and returns either free access or a payment challenge.

Parameters:

• assetUrl - Full URL to the asset (e.g., "https://example.com/api/asset/123")

Returns:

• { type: "free", url: string } - Asset is free to access
• { type: "payment_required", challenge: PaymentChallenge } - Payment required

Example:

const result = await discover("https://example.com/api/asset/123");

payAndFetch(assetUrl: string, walletAdapter: WalletAdapter, connection?: Connection): Promise<PaymentResult>

Completes the full payment flow and returns the resource.

Parameters:

• assetUrl - Full URL to the asset
• walletAdapter - Solana wallet adapter from @solana/wallet-adapter-react
• connection - Optional Solana connection (defaults to devnet/mainnet based on challenge)

Returns:

• { accessToken: string, downloadUrl: string, expiresAt: number }

Example:

const result = await payAndFetch(assetUrl, wallet);
// Use result.downloadUrl to access the resource

uploadAsset(file: File, meta: AssetMetadata, walletAdapter?: WalletAdapter, baseUrl?: string): Promise<UploadResponse>

Uploads an asset to Stream402.

Parameters:

• file - File to upload
• meta - Asset metadata:
  • title: string - Asset title
  • price: number | string - Price in USDC
  • recipient?: string - Recipient wallet address (optional, uses wallet if not provided)
  • tags?: string[] - Tags for searchability
  • description?: string - Asset description
• walletAdapter - Optional wallet adapter (used for recipient if not provided)
• baseUrl - Optional base URL of Stream402 API (defaults to current origin)

Returns:

• { assetId: string, title: string, price: number, url: string, thumbnailUrl?: string }

Example:

const result = await uploadAsset(file, {
  title: "My Image",
  price: 0.01,
  tags: ["nature"],
}, wallet);

Types

PaymentChallenge

interface PaymentChallenge {
  version: string;
  network: string;
  currency: string;
  decimals: number;
  amount: number;
  mint: string;
  recipient: string;
  expiresAt: number;
  assetId: string;
  paymentRequestToken: string;
  description?: string;
  metadata?: Record<string, unknown>;
}

PaymentResult

interface PaymentResult {
  accessToken: string;
  downloadUrl: string;
  expiresAt: number;
}

AssetMetadata

interface AssetMetadata {
  title: string;
  price: number | string;
  recipient?: string;
  tags?: string[];
  description?: string;
}

Examples

React Component Example

import React, { useState } from "react";
import { useWallet } from "@solana/wallet-adapter-react";
import { discover, payAndFetch } from "@stream402/sdk";

function AssetViewer({ assetUrl }: { assetUrl: string }) {
  const wallet = useWallet();
  const [status, setStatus] = useState<"loading" | "free" | "payment_required" | "paid">("loading");
  const [downloadUrl, setDownloadUrl] = useState<string>("");

  useEffect(() => {
    checkAsset();
  }, [assetUrl]);

  const checkAsset = async () => {
    try {
      const result = await discover(assetUrl);
      if (result.type === "free") {
        setStatus("free");
        setDownloadUrl(result.url);
      } else {
        setStatus("payment_required");
      }
    } catch (error) {
      console.error("Failed to discover asset:", error);
    }
  };

  const handlePay = async () => {
    if (!wallet.connected) {
      await wallet.connect();
    }

    try {
      const result = await payAndFetch(assetUrl, wallet);
      setStatus("paid");
      setDownloadUrl(result.downloadUrl);
    } catch (error) {
      console.error("Payment failed:", error);
    }
  };

  return (
    <div>
      {status === "loading" && <p>Loading...</p>}
      {status === "free" && <a href={downloadUrl}>Download</a>}
      {status === "payment_required" && (
        <button onClick={handlePay}>Pay to Access</button>
      )}
      {status === "paid" && <a href={downloadUrl}>Download</a>}
    </div>
  );
}

Node.js Example

import { discover, payAndFetch } from "@stream402/sdk";
import { Connection, Keypair } from "@solana/web3.js";
import { NodeWalletAdapter } from "@solana/wallet-adapter-wallets";

// Create a wallet adapter from a keypair
const keypair = Keypair.fromSecretKey(/* your secret key */);
const wallet = new NodeWalletAdapter(keypair);
const connection = new Connection("https://api.devnet.solana.com");

// Discover and pay
const result = await discover("https://example.com/api/asset/123");
if (result.type === "payment_required") {
  const paymentResult = await payAndFetch(
    "https://example.com/api/asset/123",
    wallet,
    connection
  );
  console.log("Download URL:", paymentResult.downloadUrl);
}

Requirements

• Node.js 18+
• TypeScript 5+
• Solana wallet adapter (for payment functionality)

License

MIT

Support

For issues and questions, please visit Stream402 GitHub.