How to Track Price Drops with BuyWhere API: A 2026 Developer's Guide

You want your agent to alert users when a product drops below a price, or to surface live deals. BuyWhere exposes two complementary endpoints: get_price_history (per-product history) and get_deals (country-wide discount feed). Here's how to wire them up.

Quick Answer: For a watched-product alert, poll get_price_history per SKU and compare to your threshold. For a "what's on sale right now" watcher, poll get_deals(min_discount=20, country_code=SG) periodically. Both endpoints are first-class MCP tools too.

Prerequisites

• BuyWhere API key (free signup at buywhere.ai/api-keys, 1,000 requests/month)
• Node.js 18+ or Python 3.10+
• A list of products to watch (or a category filter)

Pattern 1: Watched-product alerts

This is the case where you have a list of products the user cares about and you want to ping them when the price drops below a threshold.

Step 1 — Find products to watch

curl -s "https://api.buywhere.ai/v1/products/search?q=sony+wh-1000xm5&country_code=SG&limit=5" \
  -H "Authorization: Bearer $BUYWHERE_API_KEY" | jq '.products[].id'

Step 2 — Poll get_price_history

// watch.js
const BUYWHERE = "https://api.buywhere.ai";
const KEY = process.env.BUYWHERE_API_KEY;

async function currentPrice(productId) {
  const url = `${BUYWHERE}/v1/products/${productId}/price-history`;
  const resp = await fetch(url, { headers: { Authorization: `Bearer ${KEY}` }});
  if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
  const data = await resp.json();
  // data.history is an array of {timestamp, price, currency}; last entry is current
  return data.history.at(-1);
}

async function watch(productId, threshold) {
  const last = await currentPrice(productId);
  if (last.price <= threshold) {
    console.log(`[ALERT] ${productId} dropped to ${last.price} ${last.currency} (threshold ${threshold})`);
    // → send email, webhook, push notification, etc.
  }
}

// Run every 30 minutes
setInterval(() => watch("PRODUCT_ID", 350), 30 * 60 * 1000);

Step 3 — Persist and dedupe

To avoid re-alerting on the same drop, persist the last alerted price:

// Simple file-based dedupe
import { readFile, writeFile } from "node:fs/promises";

const STATE_FILE = "./alert-state.json";

async function getState() {
  try { return JSON.parse(await readFile(STATE_FILE, "utf8")); }
  catch { return {}; }
}

async function shouldAlert(productId, currentPrice) {
  const state = await getState();
  const last = state[productId];
  if (last && last >= currentPrice) return false; // not a new low
  state[productId] = currentPrice;
  await writeFile(STATE_FILE, JSON.stringify(state, null, 2));
  return true;
}

Pattern 2: Pull all current deals

This is the case where you want to surface "everything on sale right now" without managing a watched list.

# deals.py
import os, requests

API = "https://api.buywhere.ai"
KEY = os.environ["BUYWHERE_API_KEY"]

def fetch_deals(country="SG", min_discount=20, limit=100):
    resp = requests.get(
        f"{API}/v1/products/deals",
        params={
            "country_code": country,
            "min_discount": min_discount,
            "limit": limit,
        },
        headers={"Authorization": f"Bearer {KEY}"},
        timeout=10,
    )
    resp.raise_for_status()
    return resp.json()["products"]

if __name__ == "__main__":
    deals = fetch_deals("SG", min_discount=30)
    for p in deals:
        print(f"{p['name']} — was {p['original_price']} now {p['price']} ({p['discount_pct']}% off) at {p['merchant']}")

get_deals returns ranked results by discount_desc (largest discount first). Run every 5–15 minutes; feed into a digest email, Telegram bot, or an agent's tool result.

Pattern 3: MCP tool call

If you're embedding the watcher in an MCP-aware agent, the same lookup is one tool call:

get_price_history(product_id="abc-123")
→ { history: [{timestamp: "...", price: 379}, ...], currency: "SGD" }

get_deals(country_code="SG", min_discount=25)
→ { products: [...], total: 142 }

The MCP server at https://api.buywhere.ai/mcp exposes both. No API key copy-paste required for tools that route through the server.

Polling cadence

Rate limit math

• Free tier: 100 requests/min
• Partner tier: 1,000 requests/min

For 1,000 SKUs polled every hour, that's ~17 requests/min average — well within free tier. For 10,000 SKUs every 5 min, that's 33 requests/sec — partner tier.

Common questions

Can I get push notifications instead of polling? BuyWhere doesn't ship a webhook for price drops yet. Polling is the current pattern. If you need push, run the watcher on a cron and fire webhooks from your side.

What currency does get_price_history return? The currency of the merchant's listing at the time of the snapshot. If you want normalization, use country_code=SG to scope results and accept SGD.

Does get_price_history include sale price and original price? Yes — the history includes both price and compare_at_price when the merchant reports it. Use discount_pct for the simple comparison.

Verdict

• Watched products: get_price_history + dedupe state
• Live deal digest: get_deals(min_discount=...) on a cron
• Agent-native: both are MCP tools, no wrapper needed

Where to go next

• API keys → buywhere.ai/api-keys
• Search endpoint → buywhere.ai/docs/api-reference/search
• Deals endpoint → buywhere.ai/docs/api-reference/deals
• Price history → buywhere.ai/docs/api-reference/price-history