You can turn a URL into a PDF with a single request. Catching changes to that page takes a second, separate request. A screenshot API called Screenshot Happy describes both. Its write-up is a DEV Community article by Ghezam Capital, published September 28, 2026. The “one API call” in the headline covers only the PDF half. Monitoring is its own endpoint with its own setup.
This guide walks through both calls as that article describes them. It also covers where the approach breaks down. Everything here comes from that one product article. It is not official documentation or independent testing, so confirm endpoints, quotas and pricing in the vendor’s current docs before you build on them.
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Call one: capture a URL as a PDF
As described, the PDF capture reuses the same /screenshot endpoint that produces PNG and JPEG images. You change the format parameter to pdf. The article’s example also sets full_page=true and saves the response body to a file named page.pdf.
The parameters that matter
| Parameter | Value in the example | What the article says it does |
|---|---|---|
url |
The page to capture | The target page. The exact parameter name is not given in the summary, so check the docs. |
format |
pdf |
Switches output from image to PDF. |
full_page |
true |
Produces a single page sized to the full scrollable content. |
selector |
Not used for PDF | Captures one element. PNG/JPEG only, and incompatible with full_page. |
Shape of the request
The host and authentication scheme are not in the source material. The sketch below uses placeholders, so replace them with what the vendor’s docs specify.
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curl "https://API_HOST/screenshot?url=https%3A%2F%2Fexample.com%2Fterms&format=pdf&full_page=true"
-H "AUTH_HEADER: YOUR_KEY"
-o page.pdfOpen page.pdf afterwards. If the file is tiny or won’t open, it is probably an error message saved as a file. Open it in a text editor to read the response.
What kind of PDF you get
The article says the output is a rendering of the page as it looks on screen. It does not apply a print stylesheet. Two consequences follow:
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- You get a faithful picture of what a visitor sees, including navigation bars and banners. That suits archiving and evidence.
- You don’t get the tidy, print-optimised layout a browser’s “Save as PDF” can produce. If you want a clean article layout for reading, test a sample page first.
With full_page=true you get one tall page rather than paginated A4 or Letter sheets. That is convenient for archiving, but awkward to print.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →Call two: watch the page for changes
Monitoring is a separate POST /monitors request. You send four things:
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- The URL of the page to watch.
- A webhook URL that will receive alerts.
- An interval in minutes.
- A difference threshold.
On that schedule the service captures the page and compares the new image with the previous one. When the share of changed pixels crosses your threshold, it POSTs to your webhook. The article’s example uses a 60-minute frequency and a threshold of 5. Those are illustrative values, not recommended defaults.
The comparison is image-based, so it reacts to anything that looks different. A rewritten paragraph counts. So does a moved layout block or a new banner. It doesn’t tell you what the text said before and after.
Your webhook receiver
You need a public HTTPS endpoint that accepts a POST and answers quickly. The payload format isn’t described in the source, so read the vendor’s docs for the fields. A sensible pattern is to treat the alert as a prompt rather than as the record. When it fires, request a fresh PDF with call one and store it with a timestamp. That gives you a dated copy of the page as it stood after the change.
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- Receipt scanner and card scanner with Additional features include scanning business cards directly to Outlook, photo scanning, and receipt scanning for efficient document management
The main weakness: noisy pages
The author states that the threshold is a flat percentage of changed pixels across the whole page. Rotating ads, live timestamps, carousels and similar elements can use up that budget and trigger false alerts. In the version described, monitors cannot be limited to a selector. The suggested workaround is to raise the threshold on pages with known noisy areas.
A higher threshold has a cost. A small but important edit, such as one changed price or a single clause in a contract, may stay below it. Pages where the meaningful content is a small share of the screen are a poor fit for pixel-share monitoring. Pages with mostly static layouts suit it better.
Best Value
- Scanner type: Document
- Connectivity technology: USB
- With Auto Scan Mode, the scanner automatically detects what you're scanning
- Digitize documents and images
Where this fits
The article suggests three uses. None is backed by test results.
- Visual regression after deployments: capture key pages and see whether something shifted.
- Point-in-time archives: keep dated copies of contracts or terms pages.
- Watching third parties: track competitor pricing pages or vendor terms.
The practical question the author frames is “did this change since last time, and do I need to know about it?” Pixel comparison answers the first half. Your threshold choice decides the second.
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Reported plan details
The article reports the following. They are the author’s claims as of September 28, 2026, so check current terms before relying on them.
| Item | Reported |
|---|---|
| Free screenshots | 200 per month |
| Free monitored pages | 3, checked every 6 hours |
| Paid plans | From €9 per month, with higher quotas, faster checking and webhook alerts |
Note the last item. If webhook alerts are a paid feature, the free monitors may not notify you the way the example does. Confirm that before designing around the free tier.
Quick Recap
What to verify before depending on it
- The current endpoint names, host, authentication and parameter names.
- Whether PDF output meets your need for fidelity, using a sample of your real target page.
- How long captures are stored, and whether you must save your own copies. For legal or compliance archives, keep your own copies regardless.
- How the webhook is delivered and retried if your receiver is down.
- Whether a self-hosted headless browser would suit you better. It gives more control over print styles and element-level diffing, but you run the infrastructure yourself. The source doesn’t compare alternatives, so this is a trade-off to weigh rather than a finding.
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