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@faremeter/info

@faremeter/info centralizes metadata and helpers for producing Coinbase x402 payment requirement payloads. It wraps the shared @faremeter/types schemas with typed builders so callers can focus on business logic instead of boilerplate defaults.
  • Compatible with Node 18+ (ESM) and TypeScript 5.2+.
  • Depends on sibling packages @faremeter/types/evm and @faremeter/types/solana for address validation.

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Quick start

import { solana, evm } from "@faremeter/info";

const requirement = solana.x402Exact({
  network: "mainnet-beta",
  asset: "USDC",
  amount: "1.5",
  payTo: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
});

const fallback = evm.x402Exact({
  network: "base",
  asset: "USDC",
  amount: 5,
  payTo: "0xabc123...",
});

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Export overview

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Utility types

  • UnitInput: union of string | number used for human-readable amount inputs while preserving precision when converted to strings.
  • addX402PaymentRequirementDefaults(req): fills description and mimeType with Coinbase x402 defaults before returning the partially constructed requirement. Use it when assembling custom payloads to keep consistency with other builders.

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Solana module (solana)

Network helpers
  • KnownCluster, isKnownCluster(value): whitelist and guard for supported clusters (devnet, testnet, mainnet-beta).
  • lookupX402Network(cluster): expands a Solana cluster into the identifiers expected by downstream x402 middleware (adds the plain solana alias for mainnet-beta).
Token catalog
  • KnownSPLToken, isKnownSPLToken(token): currently limited to USDC, extendable in code.
  • lookupKnownSPLToken(cluster, token): returns the mint address and a toUnit helper for formatting amounts, or undefined when the token is unsupported on that cluster.
Requirement builders
  • x402Exact(args): returns an array of payment requirement objects (one per network alias) with scheme exact. Throws if the token/cluster pair is unknown. Internally applies a 60 second timeout to match Coinbase middleware defaults.
  • xSolanaSettlement(args): builds a single requirement using the custom @faremeter/x-solana-settlement scheme. Accepts either "sol" or a KnownSPLToken; throws for unsupported assets.

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EVM module (evm)

Network helpers
  • KnownX402Network, isKnownX402Network(name): guard the curated list of Base and SKALE network identifiers.
  • lookupKnownX402Network(name): returns chain metadata (currently just chainId) for known networks.
  • lookupX402Network(chainId): maps a numeric chainId to the known key when possible or falls back to an eip155:{chainId} string.
Asset catalog
  • KnownAsset, isKnownAsset(asset): presently supports USDC.
  • lookupKnownAsset(network, asset): resolves contract metadata, optional forwarder details, and a toUnit helper. Accepts either a known network key or numeric chainId.
  • findAssetInfo(network, assetOrInfo): convenience wrapper that accepts a raw asset name (using the catalog) or a custom ContractInfo object. Throws for unknown assets or unsupported networks.
Requirement builders
  • evm.x402Exact(args): creates a single exact scheme requirement with a 300 second timeout. Throws if the asset is unknown for the specified network.

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Usage patterns

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Multi-chain payment requirements

import { solana, evm } from "@faremeter/info";

export function buildRequirements(payToSol: string, payToEvm: string) {
  const solanaReqs = solana.x402Exact({
    network: "mainnet-beta",
    asset: "USDC",
    amount: "1.50",
    payTo: payToSol,
  });

  const evmReq = evm.x402Exact({
    network: "base",
    asset: "USDC",
    amount: 2,
    payTo: payToEvm as `0x${string}`,
  });

  return [...solanaReqs, evmReq];
}

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Custom requirement with defaults

import { addX402PaymentRequirementDefaults } from "@faremeter/info/common";

const customRequirement = addX402PaymentRequirementDefaults({
  scheme: "exact",
  network: "solana-mainnet-beta",
  payTo: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  maxAmountRequired: "10",
});

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Error handling

  • Builder functions throw when asked for unsupported assets, clusters, or networks. Surface these to integrators (e.g., HTTP 400) so they can correct configuration.
  • Catalog guards (isKnownCluster, isKnownSPLToken, isKnownAsset, isKnownX402Network) are designed for pre-validation when consuming user input.

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Extending the catalog

When adding new assets or tokens, update the relevant constants in src/solana.ts or src/evm.ts and expand the documentation accordingly. Ensure:
  • The mint/contract addresses are accurate per network.
  • toUnit implementations return stringified amounts in the denomination expected by downstream settlement logic.
  • Tests or examples cover the new asset to prevent regressions.
  • @faremeter/types: canonical x402 schemas and validation helpers.
  • @faremeter/facilitator: consumes these requirement builders when orchestrating multi-network payment flows.