Track prices and get alerts

This guide sets up a monitor that checks an Amazon product every morning and emails you when its price drops by 5% or more. Nothing is sent when the price stays the same. The same pattern works for Walmart, eBay and any other page. You need Python with requests, and your API key in SPIDRA_API_KEY.

1. Describe what to watch and when to alert

monitor = {
    "name": "Echo Dot price",
    "sources": [
        {"kind": "template", "template": "amazon-product-details", "inputs": {"products": ["B0CG1LGWR6"]}}
    ],
    "schedule": {"every": "1d", "at": "08:00", "timezone": "America/New_York"},
    "alertOn": "changed",
    "watchFields": ["price"],
    "rule": {"field": "price", "op": "drops_by_pct", "value": 5},
    "notify": {"email": {"enabled": True}},
}

The source is the Amazon product details template, which returns the price as a number. products takes ASINs or product links, several at once.
alertOn: "changed" with watchFields: ["price"] compares only the price between checks.
The rule narrows it to drops of 5% or more. Use "op": "lt", "value": 40 for “below $40” instead.
Email goes to your account’s address. Add "slack": {"webhookUrl": "..."} or a webhook to get alerts elsewhere too.

2. Create the monitor

# price_watch.py
import os
import time

import requests

API = "https://api.spidra.io/api"
HEADERS = {"Authorization": f"Bearer {os.environ['SPIDRA_API_KEY']}"}

monitor = {
    "name": "Echo Dot price",
    "sources": [
        {"kind": "template", "template": "amazon-product-details", "inputs": {"products": ["B0CG1LGWR6"]}}
    ],
    "schedule": {"every": "1d", "at": "08:00", "timezone": "America/New_York"},
    "alertOn": "changed",
    "watchFields": ["price"],
    "rule": {"field": "price", "op": "drops_by_pct", "value": 5},
    "notify": {"email": {"enabled": True}},
}

# 1. See what it will cost
estimate = requests.post(f"{API}/monitors/estimate", headers=HEADERS, json=monitor).json()
print(f"{estimate['creditsPerCheck']} credit per check, about {estimate['creditsPerMonth']} a month")

# 2. Create it (the first check runs straight away and records today's price)
created = requests.post(f"{API}/monitors", headers=HEADERS, json=monitor).json()["monitor"]
print("Monitor", created["id"], "next check", created["nextRunAt"])

# 3. Read the first check
time.sleep(30)
checks = requests.get(f"{API}/monitors/{created['id']}/checks", headers=HEADERS).json()["checks"]
print(checks[0]["status"], "-", checks[0]["summary"])

1 credit per check, about 30 a month
Monitor 73f8b2aa-56d6-41c0-9121-3e5414f88b08 next check 2026-10-25T12:00:00.000Z
completed - Started watching (1 item)

The first check recorded the current price and didn’t alert. From now on, each morning’s price is compared with the day before, and an email goes out only when it has dropped by 5% or more. nextRunAt is in UTC: 08:00 in New York is 12:00 UTC.

3. When the price drops

The alert email names the monitor, says what changed, and shows the old and new price. Read the same thing from the API with Get a Monitor Check, where each changed item looks like:

{ "key": "B0CG1LGWR6", "item": { "title": "...", "price": 39.99 }, "fields": [{ "field": "price", "previous": 49.99, "current": 39.99 }] }

(That’s the shape; your values come from the product.) Send a Test Notification shows what an alert looks like in each channel before a real one arrives.

Watch other shops

To watch	Source
Walmart products	`{"kind": "template", "template": "walmart-product-details", "inputs": {...}}`
eBay items	`{"kind": "template", "template": "ebay-item-details", "inputs": {...}}`
Any product page	A preset of a scrape with a schema that has a `price` field, as `{"kind": "preset", "presetId": "..."}`
A page’s text	`{"kind": "urls", "urls": ["https://..."]}` with `"alertOn": "page"`

Get a Template lists each template’s inputs.

Good to know

A check costs what the run costs: 1 credit per product here.
Your plan sets the fastest schedule: daily on Free, hourly on Starter, every 15 minutes on Builder, every 5 minutes on Pro.
After 5 failed checks in a row, the monitor pauses and emails you.
Prices follow Amazon’s marketplace. Set the template’s marketplace input for amazon.co.uk, amazon.de and the rest.

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Track prices and get alerts

1. Describe what to watch and when to alert

2. Create the monitor

3. When the price drops

Watch other shops

Good to know

​1. Describe what to watch and when to alert

​2. Create the monitor

​3. When the price drops

​Watch other shops

​Good to know

1. Describe what to watch and when to alert

2. Create the monitor

3. When the price drops

Watch other shops

Good to know