GoScreenAPI
Visual Monitoring V2

See exactly what changed,
pixel by pixel.

Monitor websites for visual changes with pixel-level diff highlighting, ignore regions, mobile viewport monitoring, Slack alerts, and intelligent text diff. Know exactly what changed and where.

Start for free → View pricing
Pixel-level diff Ignore regions Mobile monitoring Slack + Email alerts Text diff No credit card required

See changes highlighted in real-time

Drag the slider to compare before and after screenshots with diff overlay.

After — 12.5% changed
+ New section added
Before — Original
← Before Drag to compare After →
V2 Features

Everything you need to detect changes

Six powerful features working together to give you complete visibility into website changes.

Pixel-Level Diff Highlighting

See exactly which pixels changed between screenshots. Red overlay shows removed content, green shows additions. Semi-transparent overlays keep the original content visible beneath.

Red/Green overlay Side-by-side composite Shareable CDN URL Auto-generated
Diff Overlay Original Side-by-Side
— Removed section (red overlay)
+ Added section (green overlay)
Change detected: 12.5% pixels modified

Ignore Regions Editor

Draw rectangles on your screenshot to exclude dynamic areas like ads, timestamps, and rotating banners. Use CSS selectors or pixel coordinates. Up to 20 regions per monitor.

Visual editor CSS selectors Pixel coordinates Drag to resize
Visual Editor Draw Mode
IGNORED — .ad-banner
IGNORED
2 regions defined · Click to select, drag to resize

Mobile Viewport Monitoring

Monitor the same URL at both desktop (1440px) and mobile (375px) viewports. Independent change detection for each — catch responsive design breakages before your users do.

375px mobile 1440px desktop Independent tracking Viewport toggle
Desktop — 1440px
Mobile — 375px

Text Content Diff

See exactly what text was added, removed, or modified alongside visual changes. Side-by-side or inline view with syntax highlighting. Know if a change is visual-only or content-related.

Line-by-line diff Side-by-side view Inline unified Addition/deletion counts
text-diff.patch
+3 additions -1 deletion
10Welcome to our platform
11We offer great services
12- Pricing starts at $29/mo
12+ Pricing starts at $19/mo
13+ Now with a free tier!
14+ Limited time offer
15Contact us for details

Slack Block Kit Alerts

Rich Slack notifications with Block Kit formatting. See the composite before/after image directly in your channel. Per-monitor or global webhook configuration. One-click to view details.

Block Kit format Composite image Action buttons Per-monitor webhook
📸
GoScreenAPI 2:30 PM
🔄 Visual Change Detected
Monitor: Example Site
Change: 12.5%
Viewport: Desktop
Time: 14:30 UTC
📷 Before/After composite image
View Details View Full Image

Custom Headers & Authentication

Monitor password-protected pages and header-restricted content. Add up to 10 custom HTTP headers and basic auth credentials. All values encrypted at rest with Laravel's encryption.

Basic Auth Custom headers Encrypted storage Up to 10 headers
Header Configuration
Authorization: Basic ••••••••••
X-API-Key: sk_live_••••••••
X-Custom-Token: ••••••••••••
Basic Auth:
Username: admin
Password: ••••••••
All values encrypted at rest

Developer-friendly integrations

Rich Slack notifications and webhook payloads with all the data you need to automate your workflow.

// Slack Block Kit Notification
{
"blocks": [
{
"type": "header",
"text": "🔄 Visual Change Detected"
},
{
"type": "section",
"fields": [
"*Monitor:* Example Site",
"*Change:* 12.5%",
"*Viewport:* Desktop"
]
},
{
"type": "image",
"image_url": "https://cdn.../composite.png"
}
]
}
// Webhook POST Payload
{
"event": "visual_change",
"monitor": {
"id": 123,
"name": "Example Site",
"url": "https://example.com"
},
"change": {
"diff_percent": 12.5,
"viewport": "desktop",
"diff_image": "https://cdn.../diff.png",
"composite": "https://cdn.../composite.png",
"text_changes": {
"additions": 3,
"deletions": 1
}
},
"timestamp": "2024-01-15T14:30:00Z"
}

Up and running in 3 steps

Start monitoring visual changes in under a minute.

1

Create a monitor

Enter the URL you want to monitor. Set your check interval, diff threshold, and notification preferences. Enable mobile viewport if needed.

2

Configure detection

Define ignore regions to exclude dynamic content. Add custom headers for protected pages. Choose your alert channels — email, Telegram, Slack, or webhook.

3

Get pixel-level alerts

When a change is detected, you get an instant alert with the exact diff percentage, a composite before/after image, and a text diff showing what content changed.

Comparison

How we compare

More features, better pricing, and developer-friendly integrations.

Feature
✦ GoScreenAPI
Visualping Fluxguard ChangeTower
Pixel-level diff overlay
Composite before/after image
Ignore regions (visual editor)
Mobile viewport monitoring
Text content diff
Slack Block Kit alerts
Custom HTTP headers
Basic authentication
Webhook notifications
Telegram alerts
Perceptual hashing (pHash)
Free plan available
API access
15-minute check interval
Total features 14/14 7/14 8/14 5/14

Last updated: May 2026 · Based on publicly available feature lists

Frequently Asked Questions

Everything you need to know about Visual Monitor V2.

Visual monitoring automatically takes screenshots of your websites and detects when they change. Using perceptual hashing (pHash), it identifies meaningful visual changes while ignoring minor pixel differences like anti-aliasing or compression artifacts.

When a change is detected, the system generates a diff overlay image showing exactly which pixels changed. Red overlay indicates removed content, green overlay indicates additions. The overlay is semi-transparent so you can still see the original page content beneath.

You can define areas of a page to exclude from comparison using a visual editor (draw rectangles) or CSS selectors. This prevents dynamic content like ads, timestamps, and rotating banners from triggering false alerts. Up to 20 regions per monitor.

You can monitor the same URL at both desktop (1440px) and mobile (375px) viewport widths simultaneously. Each viewport has independent change detection — a desktop change won't affect mobile tracking and vice versa.

Alongside the visual screenshot, the system extracts the visible text content of the page. When a change is detected, it computes a line-by-line text diff showing additions, deletions, and unchanged content — similar to a Git diff.

Email, Telegram, Slack (with Block Kit formatting and composite images), and custom webhooks. You can configure a Slack webhook per monitor or set a global webhook for all monitors.

Yes. You can add custom HTTP headers (up to 10) and basic authentication credentials. All sensitive values are encrypted at rest using Laravel's encryption. Headers are decrypted only when sending the request to the screenshot worker.

Depending on your plan: every 24 hours (Free), every hour (Pro), or every 15 minutes (Business). Mobile and desktop viewports are checked independently at the same interval.

A shareable side-by-side image showing before and after screenshots with highlighted change areas. It includes a header bar with the monitor name, URL, diff percentage, and timestamp. Stored on CDN — no authentication required to view.

Yes, the free plan never expires. Monitor 1 URL with 24-hour checks, email alerts, and perceptual hashing at no cost, forever. No credit card required.

Smart storage only saves screenshots when changes exceed your threshold. This typically reduces storage by 80-90% compared to storing every screenshot. The system keeps the last 30 detected changes per monitor.

Yes. Webhook notifications send a JSON payload with all change data including diff percentage, viewport, image URLs, and text diff stats. You can use this to trigger custom workflows, update dashboards, or feed into other monitoring systems.

Start detecting visual changes today

1 monitor, pixel-level diff, email alerts. Free forever. No credit card required.

Start for free → View pricing
Free plan forever Pixel-level diff Slack + Email + Telegram No credit card
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