DEV Community: Cizze R

How to Monitor Website Changes Automatically (Visual Diff Tutorial)

Cizze R — Tue, 07 Jul 2026 12:33:26 +0000

How to Monitor Website Changes Automatically

I run a few websites and need to know immediately when something breaks. A CSS regression, a broken layout, a missing section. Manual checking doesn't scale, and text-based monitoring misses visual issues.

The {{screenshot-diff}} on Apify takes two screenshots and produces a pixel-level comparison with an overlay showing exactly what changed.

How It Works

Take a baseline screenshot of the correct state. Then take a current screenshot of the live page. The actor compares pixel by pixel and returns a diff image with changed pixels highlighted, plus a percentage telling you how much changed.

import requests, time

API_TOKEN = "YOUR_APIFY_TOKEN"

def capture_screenshot(url):
    resp = requests.post(
        "https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs",
        headers={"Authorization": f"Bearer {API_TOKEN}"},
        json={"url": url, "fullPage": True}
    )
    run_id = resp.json()["data"]["id"]
    time.sleep(15)
    items = requests.get(
        f"https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs/{run_id}/dataset/items",
        headers={"Authorization": f"Bearer {API_TOKEN}"}
    ).json()
    return items[0]["screenshotUrl"]

def compare_screenshots(baseline_url, current_url):
    resp = requests.post(
        "https://api.apify.com/v2/acts/weeknds~screenshot-comparison-tool/runs",
        headers={"Authorization": f"Bearer {API_TOKEN}"},
        json={
            "baselineImageUrl": baseline_url,
            "currentImageUrl": current_url,
            "threshold": 0.01
        }
    )
    run_id = resp.json()["data"]["id"]
    time.sleep(10)
    items = requests.get(
        f"https://api.apify.com/v2/acts/weeknds~screenshot-comparison-tool/runs/{run_id}/dataset/items",
        headers={"Authorization": f"Bearer {API_TOKEN}"}
    ).json()
    return items[0]

baseline = capture_screenshot("https://mysite.com")
current = capture_screenshot("https://mysite.com")
result = compare_screenshots(baseline, current)

print(f"Difference: {result['diffPercentage']:.2f}%")
print(f"Diff image: {result['diffImageUrl']}")

if result['diffPercentage'] > 5:
    send_alert("Website changed significantly!")

Real Uses

Deployment Verification

After every deploy, diff staging against production. If anything changed more than 2%, the deploy gets flagged before customers notice.

def verify_deploy(staging_url, production_url):
    staging_shot = capture_screenshot(staging_url)
    prod_shot = capture_screenshot(production_url)
    result = compare_screenshots(prod_shot, staging_shot)

    if result['diffPercentage'] > 2.0:
        print(f"Regression: {result['diffPercentage']:.1f}% changed")
        print(f"Diff: {result['diffImageUrl']}")
        sys.exit(1)
    else:
        print(f"Clean: {result['diffPercentage']:.1f}%")

Competitor Monitoring

Track when competitors update their landing pages. Screenshot their site daily, diff against yesterday. Silent changes become visible.

CI/CD Pipeline

Add visual regression testing to GitHub Actions. On every deployment, screenshot the live site and compare against the pre-deploy baseline. Block the deploy if visual changes exceed threshold.

What You Can Configure

baselineImageUrl and currentImageUrl are required — just point them at your screenshots.

threshold controls sensitivity. At 0.0, every single pixel difference counts. At 0.01, the actor ignores minor anti-aliasing artifacts that don't actually matter.

What It Costs

$0.005 per comparison. With the screenshot API at $0.003 per screenshot, a full compare costs about $0.011 — two screenshots plus one diff. Running 100 comparisons a day costs around $1.10. Way cheaper than any commercial visual regression service.

How to Take Website Screenshots Programmatically (Free API Tutorial)

Cizze R — Tue, 07 Jul 2026 12:33:20 +0000

How to Take Website Screenshots Programmatically

Sometimes curl isn't enough. You need to see what a page actually renders — complete with lazy-loaded images, JavaScript widgets, and the fold.

The {{screenshot-api}} on Apify captures full-page or viewport screenshots of any URL. Here's how to use it.

Quick Start

import requests, time

API_TOKEN = "YOUR_APIFY_TOKEN"
ACTOR_ID = "weeknds~website-screenshot-api"

resp = requests.post(
    f"https://api.apify.com/v2/acts/{ACTOR_ID}/runs",
    headers={"Authorization": f"Bearer {API_TOKEN}"},
    json={
        "url": "https://news.ycombinator.com",
        "fullPage": True,
        "viewportWidth": 1280,
        "viewportHeight": 720
    }
)

run_id = resp.json()["data"]["id"]
time.sleep(15)

items = requests.get(
    f"https://api.apify.com/v2/acts/{ACTOR_ID}/runs/{run_id}/dataset/items",
    headers={"Authorization": f"Bearer {API_TOKEN}"}
).json()

screenshot_url = items[0]["screenshotUrl"]
print(f"Screenshot: {screenshot_url}")

Also works with curl:

curl -X POST "https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs" \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com", "fullPage": true}'

curl "https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs/RUN_ID/dataset/items" \
  -H "Authorization: Bearer YOUR_TOKEN"

What You Can Configure

url is the only required field. Everything else has sensible defaults.

fullPage defaults to true and captures the entire scrollable page. Set it false for just the viewport.

viewportWidth and viewportHeight default to 1280x720. Good for desktop previews, but bump it up for retina-quality output.

waitUntil defaults to networkidle2, meaning it waits until at most 2 network connections are active for 500ms. This catches most lazy-loaded content. For simpler pages, load or domcontentloaded is faster.

format is png by default. Switch to jpeg with a quality value if file size matters more than crispness.

Real-World Uses

Social Media Preview Generator

Generate Open Graph images by screenshooting a dedicated preview page. Build an HTML template, serve it somewhere, screenshot it at 1200x630. Instant og:image without touching Photoshop.

Daily Website Snapshots

Take a screenshot of your site every day and archive it. When someone asks "when did that change," you have the answer. Pair it with the screenshot comparison tool to get automatic alerts when something shifts.

Competitor Landing Page Archive

Track how competitors update their homepages over time. Screenshot their site weekly and flip through the archive to spot redesigns, new features, or messaging changes.

Handling Lazy-Loaded Content

The networkidle2 wait strategy catches most lazy-loaded images and widgets. For infinite-scroll pages, you can't capture everything in one shot — screenshot individual sections instead.

What It Costs

$0.003 per screenshot. That's 333 screenshots for a dollar. Running your own headless Chrome instance costs more in compute alone — and you still have to deal with proxy rotation, CAPTCHAs, and retry logic. If you're doing anything interesting with screenshots, I'd love to hear about it.

How I Built 7 Apify Actors and Started Earning Passive Income from Web Scraping

Cizze R — Tue, 07 Jul 2026 12:28:53 +0000

How I Built 7 Apify Actors and Started Earning Passive Income from Web Scraping

A few weeks ago I had zero Apify actors. Now I have seven, all published on the Apify Store, monetized with pay-per-event pricing, and slowly building a passive income stream.

Here's exactly how I did it — the strategy, the tech stack, the mistakes, and what I'd do differently.

The Strategy: Zero Competition

Most new Apify developers go after hot categories. LinkedIn scrapers, Amazon product extractors, Twitter data. Makes sense — those have demand. But they also have dozens of established actors with hundreds of reviews.

I took the opposite approach. Find niches with zero existing actors.

This means lower total addressable market, but 100% of whatever traffic exists goes to you. No competing on price, no fighting for reviews, no SEO war against actors with years of history.

How I found the niches:

Browsed Apify Store categories sorted by actor count
Searched for common developer pain points with no existing Apify solution
Checked search volume for "[keyword] API" and "[keyword] scraper"
Verified zero results on Apify Store for each candidate

The winners: domain intelligence, screenshot comparison, Swedish company registry, IP geolocation, QR code generation, and link metadata extraction.

The Tech Stack

Every actor uses the same foundation. Apify Python SDK v3.4 handles input/output, storage, proxy, and deployment. Playwright for JavaScript-heavy sites and screenshots. aiohttp for lightweight API scraping (way faster than a full browser). Pillow for image processing.

Deployment is one command: apify push

The Actors

WHOIS, DNS, SSL, and tech stack in one API call. Uses socket + ssl + python-whois for data collection, no external API dependency. $0.005 per run.

Full-page screenshots via Playwright. Handles lazy-loading, infinite scroll, and viewport sizing. $0.003 per run.

Open Graph, Twitter Cards, JSON-LD, and meta tags from any URL. Uses aiohttp for speed — no browser overhead. $0.002 per run.

Pixel-level visual comparison with an overlay showing exactly what changed. Built with Pillow for image processing. Zero existing competitors in this niche. $0.005 per run.

Official Bolagsverket scraper. Parses Next.js __NEXT_DATA__ payloads for structured extraction. $0.003 per run.

IP geolocation with multi-provider fallback (ip-api.com then ipinfo.io). $0.003 per run.

QR codes in PNG/SVG via qrcode + Pillow. Pure Python, no external API. $0.002 per run.

Pricing Strategy

All actors use pay-per-event pricing, meaning users only pay when the actor actually runs. No subscriptions, no minimums.

The price range of $0.002 to $0.005 is deliberate. Low enough that nobody thinks twice about trying it, high enough that volume adds up.

Apify takes a 20% commission plus platform costs for compute, proxy, and storage. On a $0.005 run, the developer keeps roughly $0.002 to $0.003 after costs.

At 1,000 runs per month per actor, that's $14 to $21 per month per actor. Across 7 actors, potentially $100 to $150 per month. Not life-changing, but it covers API bills and compounds as the actors gain reviews and search ranking.

What I'd Do Differently

Start with one high-demand actor first. The zero-competition strategy is valid, but mixing in one higher-demand category — even with competition — would drive faster initial revenue.

Build distribution before building more actors. The hard part isn't building, it's getting discovered. I should have written tutorials and set up content marketing before actor number three.

Add free tier runs. A few free runs per month gets usage numbers up, which helps Store ranking. I'm adding this to all actors.

Cross-link actors in every README. Users who need screenshots might also need screenshot comparison. Users doing company research might also want domain intelligence.

What's Next

I'm building a broken link checker, favicon grabber, and EXIF metadata extractor — all in zero-competition niches. Each actor gets a dedicated tutorial and GitHub usage repo.

The goal is 15 actors by end of month, each with at least one published tutorial driving organic traffic. If you're building something on Apify too, let me know — always interested in what other devs are shipping.

How to Extract Metadata from Any URL in 5 Lines of Code (Free API Tutorial)

Cizze R — Tue, 07 Jul 2026 12:28:46 +0000

How to Extract Metadata from Any URL in 5 Lines of Code

Every time you paste a link into Slack, Discord, or Twitter, the platform fetches that page's metadata — title, description, image, author — and renders a rich preview. That's Open Graph and Twitter Cards at work.

Here's how to do the same thing in your own app, using the {{metadata-extractor}} on Apify.

What You Get

For any URL, the actor returns Open Graph tags, Twitter Cards, JSON-LD structured data, standard meta tags, and technical details like favicon and canonical URL. All in one JSON response. No browser needed — the actor uses aiohttp for sub-second extraction.

Quick Start

import requests

API_URL = "https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/run-sync-get-dataset-items"
API_TOKEN = "YOUR_APIFY_TOKEN"

response = requests.post(
    f"https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs",
    headers={"Authorization": f"Bearer {API_TOKEN}"},
    json={"url": "https://example.com"}
)

run_id = response.json()["data"]["id"]

results = requests.get(
    f"https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs/{run_id}/dataset/items",
    headers={"Authorization": f"Bearer {API_TOKEN}"}
)

metadata = results.json()[0]
print(f"Title: {metadata['title']}")
print(f"Description: {metadata['description']}")
print(f"Image: {metadata.get('og:image', 'No image')}")

Or with curl:

curl -X POST "https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs" \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com"}'

curl "https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs/RUN_ID/dataset/items" \
  -H "Authorization: Bearer YOUR_TOKEN"

Building a Link Preview Card

def build_preview_card(url):
    import requests, time

    resp = requests.post(
        "https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs",
        headers={"Authorization": f"Bearer {API_TOKEN}"},
        json={"url": url}
    ).json()

    run_id = resp["data"]["id"]
    time.sleep(3)

    items = requests.get(
        f"https://api.apify.com/v2/acts/weeknds~link-preview-metadata-extractor/runs/{run_id}/dataset/items",
        headers={"Authorization": f"Bearer {API_TOKEN}"}
    ).json()

    meta = items[0] if items else {}

    return f"""
    <div class="link-preview">
        <img src="{meta.get('og:image', '')}"
             alt="{meta.get('og:title', meta.get('title', ''))}"
             onerror="this.style.display='none'" />
        <div class="preview-text">
            <h4>{meta.get('og:title', meta.get('title', 'Unknown'))}</h4>
            <p>{meta.get('og:description', meta.get('description', ''))}</p>
            <small>{meta.get('og:site_name', '')}</small>
        </div>
    </div>
    """

Real-World Uses

Slack Bot Link Unfurling

Connect to Slack's Events API, listen for link_shared events, call the metadata extractor, and post an unfurl. Works exactly like native Slack link previews.

SEO Audit Tool

Batch-check metadata across your site to find missing Open Graph tags. Every page without og:title and og:description is losing clicks on social media.

Content Aggregator

Pull structured data from blog posts, news articles, and product pages. The JSON-LD extraction gives you schema.org markup — articles have author and publish date, products have price and availability, events have location and time.

Why Not Build It Yourself

You could write your own metadata extractor. Fetch the HTML, parse meta tags, handle redirects. Not hard. But then you deal with encoding detection (sites that lie about their charset), redirect chains (short URLs, tracking links), JavaScript-rendered meta tags, and nested JSON-LD parsing.

The actor handles all of this. One endpoint, clean JSON back.

At $0.002 per run, you can extract metadata from 500 URLs for a dollar. For most use cases — link unfurling, SEO audits, content aggregation — that's way cheaper than running your own extraction infrastructure. If you need metadata from a specific type of page the actor doesn't handle yet, let me know. I actively maintain it.

Best Free & Low-Cost Web Scraping APIs on Apify in 2026

Cizze R — Tue, 07 Jul 2026 12:28:45 +0000

Best Free & Low-Cost Web Scraping APIs on Apify in 2026

Apify's marketplace now has over 20,000 actors — automated tools that handle everything from web scraping to AI data extraction. The best part? Many of the most useful ones cost less than a cent per run.

I've spent the last few weeks building and testing Apify actors across multiple categories. Here are the ones worth your time in 2026.

Need to know everything about a domain in one API call? This actor pulls WHOIS records, DNS resolution (A, AAAA, MX, NS, TXT), SSL certificate details, and technology stack detection — all in structured JSON.

Use it for lead enrichment, security audits, or competitor analysis. $0.005 per run.

Sometimes you just need to see what a website looks like. This actor captures full-page or viewport screenshots via Playwright and returns them as base64 or a direct URL.

Good for visual monitoring, social media previews, or archival. $0.003 per run.

Extract Open Graph tags, Twitter Cards, JSON-LD structured data, and standard meta tags from any URL. Think of it as a programmable link preview generator.

Perfect for link unfurling, SEO analysis, or content aggregation. $0.002 per run.

Visual regression testing made simple. This actor takes two screenshots and produces a pixel-level diff with an overlay image showing exactly what changed.

Use it for UI testing, competitor monitoring, or deployment verification. $0.005 per run.

Need official Swedish company data? This actor scrapes Bolagsverket (Sweden's company registry) and returns structured data including registration numbers, addresses, and officer information.

Works for business verification, compliance checks, or market research in Sweden. $0.003 per run.

Simple, fast IP geolocation. Drop in an IP and get country, city, ISP, ASN, and timezone data. Uses multiple free providers with automatic fallback.

Good for fraud detection, content localization, or analytics enrichment. $0.003 per run.

Generate QR codes programmatically — PNG or SVG output, customizable colors, sizes, and error correction levels. No external API dependency.

Useful for invoice generation, event tickets, or product labeling. $0.002 per run.

Why These Beat Building Your Own

Every actor above handles infrastructure you'd otherwise spend days setting up. Proxy rotation, anti-bot bypass, auto-scaling, REST API generation — all built in. They even work inside Claude, Cursor, and Windsurf via MCP.

At $0.002 to $0.005 per run, you'd spend more on electricity running your own server. If you've got a scraping problem that needs a custom solution, I'm active on the platform — reach out.

DEV Community: Cizze R

How to Monitor Website Changes Automatically (Visual Diff Tutorial)

How to Monitor Website Changes Automatically

How It Works

Real Uses

Deployment Verification

Competitor Monitoring

CI/CD Pipeline

What You Can Configure

What It Costs

How to Take Website Screenshots Programmatically (Free API Tutorial)

How to Take Website Screenshots Programmatically

Quick Start

What You Can Configure

Real-World Uses

Social Media Preview Generator

Daily Website Snapshots

Competitor Landing Page Archive

Handling Lazy-Loaded Content

What It Costs

How I Built 7 Apify Actors and Started Earning Passive Income from Web Scraping

How I Built 7 Apify Actors and Started Earning Passive Income from Web Scraping

The Strategy: Zero Competition

The Tech Stack

The Actors

{{domain-intel}}

{{screenshot-api}}

{{metadata-extractor}}

{{screenshot-diff}}

{{swedish-companies}}

{{ip-geo}}

{{qr-generator}}

Pricing Strategy

What I'd Do Differently

What's Next

How to Extract Metadata from Any URL in 5 Lines of Code (Free API Tutorial)

How to Extract Metadata from Any URL in 5 Lines of Code

What You Get

Quick Start

Building a Link Preview Card

Real-World Uses

Slack Bot Link Unfurling

SEO Audit Tool

Content Aggregator

Why Not Build It Yourself

Best Free & Low-Cost Web Scraping APIs on Apify in 2026

Best Free & Low-Cost Web Scraping APIs on Apify in 2026

{{domain-intel}}

{{screenshot-api}}

{{metadata-extractor}}

{{screenshot-diff}}

{{swedish-companies}}

{{ip-geo}}

{{qr-generator}}

Why These Beat Building Your Own