highwire.js

highwire.js is a small browser library for merchants integrating the Gateway API directly (server-to-server). Direct integrations forward card data from your backend, so the risk systems screening the charge — Stripe Radar under the hood — never see the shopper's browser: no device fingerprint, no referrer, no time-on-page. Legitimate payments look riskier than they are, and approval rates suffer.

highwire.js runs on your checkout page, collects that missing context, and returns an opaque blob. You forward the blob with your payment request, and the gateway attaches the signals to the charge during risk screening. The library never touches card data and makes no network requests of its own.

How it works

1. On your checkout page, highwire.js collects device and page context — never card data.
2. When the shopper submits, collect() returns an opaque base64URL blob.
3. Your frontend sends the blob to your server with the rest of the checkout form, and your server forwards it unchanged as deviceData on POST /payments/auth-and-capture.