How to Extract Email Addresses from a Website
Finding publicly listed contact email addresses across multiple pages of a website requires fetching each page and applying pattern matching. Doing this at scale means handling pagination, varying page structures, and consistent data delivery.
Step-by-Step Guide
Fetch the target page
Send the URL to the AlterLab API to retrieve the full HTML content, including any dynamically loaded contact sections.
Apply regex pattern matching
Use a standard email regex pattern to extract all email addresses from the returned HTML. Filter out common no-reply or placeholder addresses as needed.
Deduplicate and validate results
Remove duplicates and validate the format of extracted addresses before storing them.
Crawl additional pages
Repeat the process for contact, about, and team pages on the same domain to maximize coverage.
Code Example
import requests
import re
def extract_emails(url: str, api_key: str) -> list[str]:
response = requests.post(
"https://alterlab.io/api/v1/scrape",
headers={"X-API-Key": api_key, "Content-Type": "application/json"},
json={"url": url},
)
html = response.json().get("html", "")
pattern = r'[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}'
return list(set(re.findall(pattern, html)))
emails = extract_emails("https://example.com/contact", "YOUR_API_KEY")
print(emails)Replace YOUR_API_KEY with your key from the . No credit card required.
Try this yourself with AlterLab
Run this tutorial on live websites with AlterLab's API. Free tier includes 5,000 requests — no credit card required.
Frequently Asked Questions
Can I extract emails that are only visible after JavaScript loads?
Yes — enable `render_js: true` in your request to execute JavaScript before extraction. This reveals emails loaded via contact forms or dynamic content blocks.
Is extracting publicly listed emails legal?
Extracting publicly listed contact information may vary in legality by jurisdiction. Always review the target website's terms of service and comply with applicable data protection regulations such as GDPR in your jurisdiction.
Responsible Use
AlterLab is designed for extracting publicly available data. Always review the terms of service for any website you access, respect robots.txt directives, and ensure your use case complies with applicable laws in your jurisdiction.
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