@stripe402/core

Protocol types, constants, header encoding/decoding, HMAC identity derivation, and error types for the stripe402 protocol. Zero external dependencies (Node.js crypto only).

Install

npm install @stripe402/core

Usage

Header encoding/decoding

import { encodeHeader, decodeHeader } from '@stripe402/core'

const encoded = encodeHeader({ amount: 500, currency: 'usd' })
const decoded = decodeHeader<{ amount: number; currency: string }>(encoded)

Client identity derivation

import { deriveClientId } from '@stripe402/core'

// Deterministic: same card fingerprint + server secret = same client ID
const clientId = deriveClientId(cardFingerprint, serverSecret)

Unit conversion

import { unitsToCents, unitsToDollars, UNITS_PER_CENT } from '@stripe402/core'

unitsToCents(500)    // 5 (cents)
unitsToDollars(500)  // "0.05"

Types

Key types exported: PaymentRequiredResponse, PaymentPayload, PaymentResponse, RouteConfig, Stripe402ServerConfig, Stripe402ClientConfig, Stripe402Store, ClientRecord, TransactionRecord.