Preview a rate

Show a live rate with pulse.rates.preview — no order created — proxied through a thin backend route for the client.

A quote is a locked price; creating one moves no money and creates no order. rates.preview wraps it and reshapes it for display.

import { type EngineNetwork } from '@pulsebyshiga/node';

export async function previewCollectionRate(payload: {
  from: string; // e.g. 'USDC'
  to: string; // e.g. 'NGN'
  amount: string; // decimal string in `from`
  network?: EngineNetwork; // UPPERCASE — engine surface
}) {
  const rate = await pulse.rates.preview(payload);
  // { rate, youSend, youReceive, expiresAt, quoteId }
  return rate;
}

EngineNetwork (the engine surface used by rates, quotes, offramp, onramp) is UPPERCASE — BASE, POLYGON, ARBITRUM, OPTIMISM, ETHEREUM, BSC. This differs from the lowercase Network used by collectionSessions.create. Pass the casing that matches the call you’re making.

Expose it as a thin proxy route

The API key stays on your server. Expose rates.preview behind a thin route — for example POST /api/pulse/rate — that simply forwards the request and returns the reshaped rate:

// Express — a thin proxy so the browser never sees the key
app.post('/api/pulse/rate', async (req, res) => {
  const rate = await previewCollectionRate(req.body);
  res.json(rate);
});

Your frontend’s useRate() hook and <PulseRate> component call this route to show a live rate with no key on the client. Both are documented in the frontend SDK reference; their theming options are covered in Theming.