@klappay/node

Official Node.js SDK for the Klap Core API — non-custodial crypto payments. Install it into your own backend project; it is a library only — not meant to be run as a standalone script, and not for browser use (it handles secret API keys, which must never reach client-side code).

Built on top of @klappay/types — the same request/response contracts the API itself uses, so the SDK is always in sync with the actual API shape.

Install

npm install @klappay/node

Quick start

import { createClient } from '@klappay/node'

const klap = createClient({
  baseUrl: 'https://your-klap-api-host', // no hardcoded default — or set KLAP_BASE_URL and omit this
  apiKey: process.env.KLAP_API_KEY, // or just set KLAP_API_KEY and omit this too
})

const charge = await klap.charges.create({
  amount: 49.9,
  acceptedPayments: [{ token: 'USDC', network: 'base' }],
})

try {
  const confirmed = await charge.waitForConfirmation({ timeoutMs: 60 * 60_000 })
  console.log('Paid!', confirmed.amountReceived)
} catch (err) {
  // ChargeExpiredError | ChargeUnderpaidError | WaitTimeoutError — see docs/errors.md
}

Documentation

Full docs live at docs/ on GitHub, and as a browsable site at node-sdk.klappay.com. The site also publishes llms.txt and llms-full.txt — plain-text, LLM-friendly versions of these docs, regenerated on every deploy, for feeding an agent or MCP server.

| Doc | Covers | |---|---| | docs/getting-started.md | Install, client setup, your first charge | | docs/charges.md | The core resource — create, list, paginate, waitForConfirmation/waitForSettlement in depth | | docs/webhooks.md | Registering webhooks, verifying signatures, constructEvent | | docs/recipients.md | Registering trusted split recipients, and referencing them by recipientId in a charge split | | docs/distributions.md | Discovering and streaming claimable 0xSplits payouts — for keepers/bots, not a typical merchant integration | | docs/networks.md | The live (token, network) capability matrix — build a payment-method picker instead of hardcoding it | | docs/metrics.md | Ad-hoc analytics over your charges/transactions/distributions data | | docs/errors.md | Every error class the SDK throws, and when | | docs/sandbox-testing.md | Simulating any charge event end-to-end with no real on-chain activity | | docs/tree-shaking.md | Subpath imports for minimal bundles — matters for serverless cold starts too, not just the browser |

License

MIT — see LICENSE.