@t402/svm

SVM (Solana Virtual Machine) implementation of the t402 payment protocol using the Exact payment scheme with SPL Token transfers.

Installation

``bash
npm install @t402/svm
`

Overview

This package provides three main components for handling t402 payments on Solana:

- Client - For applications that need to make payments (have wallets/signers)
- Facilitator - For payment processors that verify and execute on-chain transactions
- Service - For resource servers that accept payments and build payment requirements

Package Exports

$3

V2 Protocol Support - Modern t402 protocol with CAIP-2 network identifiers

Client:
- ExactSvmClient - V2 client implementation using SPL Token
- toClientSvmSigner(keypair) - Converts Solana keypairs to t402 signers
- ClientSvmSigner - TypeScript type for client signers
- ClientSvmConfig - Optional RPC configuration

Facilitator:
- ExactSvmFacilitator - V2 facilitator for payment verification and settlement
- toFacilitatorSvmSigner(keypair) - Converts Solana keypairs to facilitator signers
- FacilitatorSvmSigner - TypeScript type for facilitator signers
- FacilitatorRpcClient - RPC client interface

Service:
- ExactEvmServer - V2 service for building payment requirements

Utilities:
- Network validation, asset info lookup, amount formatting, transaction encoding

$3

V1 Protocol Support - Legacy t402 protocol with simple network names

Exports:
- ExactSvmClientV1 - V1 client implementation
- ExactSvmFacilitatorV1 - V1 facilitator implementation
- NETWORKS - Array of all supported V1 network names

Supported V1 Networks:
`typescript
[
"solana", // Mainnet
"solana-devnet", // Devnet
"solana-testnet" // Testnet
]
`

$3

Convenience builder for creating fully-configured SVM clients

Exports:
- createSvmClient(config) - Creates t402Client with SVM support
- SvmClientConfig - Configuration interface

What it does:
- Automatically registers V2 wildcard scheme (solana:*)
- Automatically registers all V1 networks from NETWORKS
- Optionally applies payment policies
- Optionally uses custom payment selector

Example:
`typescript
import { createSvmClient } from "@t402/svm/client";
import { toClientSvmSigner } from "@t402/svm";
import { createKeyPairSignerFromBytes } from "@solana/kit";
import { base58 } from "@scure/base";

const keypair = await createKeyPairSignerFromBytes(
base58.decode(process.env.SVM_PRIVATE_KEY)
);
const signer = toClientSvmSigner(keypair);

const client = createSvmClient({ signer });
// Ready to use with both V1 and V2!
`

Version Differences

$3


- Network format: CAIP-2 (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp)
- Wildcard support: Yes (solana:*)
- Payload structure: Partial (core wraps with metadata)
- Extensions: Full support
- Transaction: Pre-signed by client, completed by facilitator

$3

- Network format: Simple names (solana-devnet)
- Wildcard support: No (fixed list)
- Payload structure: Complete
- Extensions: Limited
- Transaction: Pre-signed by client, completed by facilitator

Usage Patterns

$3

`typescript
import { createSvmClient } from "@t402/svm/client";
import { wrapFetchWithPayment } from "@t402/fetch";

const client = createSvmClient({ signer: mySvmSigner });
const paidFetch = wrapFetchWithPayment(fetch, client);
`

$3

`typescript
import { t402Client } from "@t402/core/client";
import { ExactSvmClient } from "@t402/svm";
import { ExactSvmClientV1 } from "@t402/svm/v1";

const client = new t402Client()
.register("solana:*", new ExactSvmClient(signer))
.registerSchemeV1("solana-devnet", new ExactSvmClientV1(signer))
.registerSchemeV1("solana", new ExactSvmClientV1(signer));
`

$3

`typescript
import { t402Client } from "@t402/core/client";
import { ExactSvmClient } from "@t402/svm";

const client = t402Client.fromConfig({
schemes: [
{ network: "solana:*", client: new ExactSvmClient(signer) },
{
network: "solana-devnet",
client: new ExactSvmClientV1(signer),
t402Version: 1
}
]
});
`

Supported Networks

V2 Networks (via CAIP-2):
- solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp - Mainnet Beta
- solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 - Devnet
- solana:4uhcVJyU9pJkvQyS88uRDiswHXSCkY3z - Testnet
- solana:* - Wildcard (matches all Solana networks)

V1 Networks (simple names):
- solana - Mainnet
- solana-devnet - Devnet
- solana-testnet - Testnet

Asset Support

Supports SPL Token and Token-2022 program tokens:
- USDC (primary)
- Any SPL token with associated token accounts
- Automatically detects token program (Token vs Token-2022)

Transaction Structure

The exact payment scheme uses SPL Token TransferChecked instruction with:
- Compute budget optimizations (unit limit + price)
- Source/destination ATAs (Associated Token Accounts)
- Partial signing (client signs, facilitator completes and submits)

Development

`bash


Build

pnpm build

Test

pnpm test

Integration tests

pnpm test:integration

Lint & Format

pnpm lint
pnpm format
`

Related Packages

- @t402/core - Core protocol types and client
- @t402/fetch - HTTP wrapper with automatic payment handling
- @t402/evm - EVM implementation
- @t402/ton - TON implementation
- @t402/tron - TRON implementation
- @t402/near - NEAR Protocol implementation
- @t402/aptos - Aptos implementation
- @t402/tezos - Tezos implementation
- @t402/polkadot - Polkadot Asset Hub implementation
- @t402/stacks - Stacks implementation
- @t402/cosmos` - Cosmos (Noble) implementation