MONITORING

Know the moment your website changes

A standard uptime check confirms a page responds. It says nothing about whether the page still looks right. Compare a scheduled screenshot against a stored baseline and get a mismatch signal the moment something visual breaks.

imageUrl baseline
Compare against a stored reference
mismatchPercentage
A number you can alert on
Any schedule
Cron, CI, or a workflow tool
Install:curl -X POST https://api.prod.ss.snapshot-site.com/api/v3/compare
Auth:x-snapshotsiteapi-key: YOUR_API_KEY
Get started for free
Monitoring check
Good fits
Status pages and customer-facing dashboards
Pages a broken deploy would visually break silently
Partner or affiliate pages outside your direct control
Any page where 200 OK isn't proof it looks right

Baseline, capture, compare, alert

The pattern is simple and reuses the same compare endpoint used for release reviews: store a known-good screenshot once, then compare every new capture against it on a schedule.

1

Store a baseline

Capture the page once when it's known to be correct, and keep that image as your reference.

2

Capture on a schedule

Run the same capture every few minutes or hours via cron, CI, or a workflow tool.

3

Compare against imageUrl

Diff the new capture against the stored baseline, not against another live page.

4

Refresh the baseline on real changes

Update the reference image whenever the page changes on purpose, so intentional deploys don't trigger false alerts.

Quick start

Set up a monitor

1

Capture and store a baseline screenshot for the page you want to monitor

2

Schedule a job that captures the page again on an interval

3

Compare the new capture against the stored baseline with /api/v3/compare

4

Route mismatchPercentage above your threshold to Slack or an alerting tool

Example: scheduled check

Monitor

Compare a live page against a stored baseline

Detect drift from a known-good version instead of comparing two live captures.

curl --request POST \
  --url https://api.prod.ss.snapshot-site.com/api/v3/compare \
  --header 'Content-Type: application/json' \
  --header 'x-snapshotsiteapi-key: YOUR_API_KEY' \
  --data '{
    "before": {"imageUrl": "https://cdn.example.com/baselines/status-page.png"},
    "after": {"url": "https://status.example.com", "width": 1440, "fullSize": true, "hideCookie": true},
    "threshold": 0.1
  }'

Related resources

Visual Uptime MonitoringAutomated Screenshot Evidence for Affiliate and Partner Compliance MonitoringTuning the threshold Parameter in the Visual Diff APIRate Limits, Retries, and BatchingAutomate Website Change Monitoring with n8n and SlackCatch Landing Page Defacement and Hacks Automatically with n8n