Browser helpers (@payinference/sdk-js)

@payinference/sdk-js is a small, deliberately limited package for the checkout page. It contains no authentication and no PayInference API access, because the browser must never talk to PayInference directly.

text

browser ──(your endpoint, your auth)──▶ your backend ──@payinference/sdk-node──▶ PayInference

What it gives the frontend: shared types for the decision your backend chooses to forward, a typed fetch helper for your endpoint, and a card-data guard.

Types#

import type { ClientDecision, DecisionAction, Provider } from '@payinference/sdk-js';

// ClientDecision is the safe subset a backend may forward to the browser:
// { decision_id, action, route, reason_codes, ttl_ms }

Calling your backend#

import { BackendDecisionClient } from '@payinference/sdk-js';

const client = new BackendDecisionClient({
  endpoint: '/api/checkout', // YOUR endpoint, YOUR auth
  headers: { 'x-csrf-token': token }, // whatever your app uses
});

const decision = await client.getDecision({ order_id: 'order_456', amount: 14900 });

The payload goes to your backend, which calls PayInference server-side and returns whatever subset of the decision you deem safe.

Helpers#

import { shouldProceed, requiresStepUp, isHeld, isExpired } from '@payinference/sdk-js';

if (isHeld(decision)) {
  showPendingReview(); // hold: paused until review/approval completes
} else if (requiresStepUp(decision)) {
  startThreeDS();
} else if (shouldProceed(decision)) {
  openPspSession(decision.route!.primary_provider);
} else {
  showPaymentUnavailable(); // block, or no route
}

// Decisions go stale; re-request instead of acting on an old one.
if (isExpired(decision, decidedAtMs)) {
  refreshDecision();
}

Card-data guard#

BackendDecisionClient.getDecision() refuses to send payloads containing card-data-shaped keys (card_number, pan, cvv, cvc, expiry, and variants), throwing before any request is made. Card details belong in your PSP's fields only. The guard is also exported directly:

import { assertNoCardData } from '@payinference/sdk-js';
assertNoCardData(payload); // throws if the payload looks like card data

What this package will not do#

Hold or transmit an API key
Call the PayInference API
Collect or forward card data

If you find yourself wanting any of those in the browser, the integration is shaped wrong; move the logic to your backend and see Backend checkout integration.