Amazon Price Monitoring API for AI Agents

FastAF’s Amazon endpoint returns Amazon product data as JSON, so an agent or a cron job can check prices on a schedule without running its own scraper. You pay per call (x402, $0.003 per call per our OpenAPI) or start with 500 free credits every month after email verification.

How it works

1. Call GET https://api.fastaf.co/x402/v1/amazon (or the MCP tool amazon_product) with resource=product, an ASIN and marketplace domain (or resource=search with query).
2. Store the price fields you care about.
3. Re-run on your schedule and alert on changes.

Pair it with /x402/v1/walmart, /x402/v1/ebay and /x402/v1/shopping (Google Shopping) to compare the same product across stores.

Honest comparison

FastAF does not store price history or send alerts: you schedule the calls and keep the history. Dedicated price-tracking SaaS tools include dashboards and alerts out of the box; FastAF is the data layer for agents and developers who want to build their own.

Pricing

Pricing: 500 free credits every month after email verification; x402 pay-per-call from $0.003; optional prepaid credit packs from $10 for 20,000 credits, without expiry.

Pricing source: FastAF OpenAPI, read October 27, 2026. Live payment challenges are authoritative.

Amazon product/search calls use 1 API-key credit. The live x402 challenge is 3000 atomic USDC ($0.003), verified October 27, 2026.

How should an agent track prices?

Request resource=product with an ASIN and marketplace domain. Store the source URL, timestamp, marketplace and displayed currency with each observation; price is a display string, so parse it carefully.

What should you validate?

Check returned fields before using them in an agent decision. Missing fields are not evidence of zero values; preserve provenance and use bounded retries.

How do you make a real request?

This example calls Amazon API using its documented input. Save the API key from the signup email, confirm your email and set FASTAF_API_KEY in your server environment.

curl --fail-with-body -H "Authorization: Bearer $FASTAF_API_KEY" 'https://api.fastaf.co/v1/amazon?resource=product&asin=B07FZ8S74R&domain=com'

# pip install fastaf-sdk
import os
from fastaf import FastAF

with FastAF(os.environ["FASTAF_API_KEY"]) as client:
    data = client.request("amazon", {"resource":"product","asin":"B07FZ8S74R","domain":"com"})
    print(data)

Amazon product JSON for resource=product: ASIN, title, displayed price, availability_status, average_rating and total_reviews. Other resource modes return their own search, offer or bestseller data.

The example costs 1 credits after the trial. Alternatively, this endpoint costs $0.003 per successful x402 call at the default configuration; FastAF x402 calls start at $0.003. These are separate billing modes.

For x402, request the same parameters under /x402/v1/amazon without an API key, validate the live PAYMENT-REQUIRED challenge, then sign and retry with a payment-aware client. A bare curl request returns HTTP 402 and does not pay; unsupported higher-cost options require API-key billing.

Frequently asked questions