Step 1 — Install the extension
The extension is a small add-on for Google Chrome. It takes about two minutes to install.
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Open Chrome Extensions
In Chrome, click the three dots (top right) → Extensions → Manage Extensions.
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Enable Developer Mode
Toggle the Developer Mode switch in the top-right corner of the Extensions page.
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Load the extension
Click Load unpacked. A file browser opens — navigate into the extracted folder and open the /src subfolder. The folder may look empty — that's normal, Chrome reads hidden files. Click Select Folder (or OK). The MailFella extension will appear in your extensions list.
Tip: Pin the extension to your toolbar after installing. Click the puzzle piece icon in Chrome → find MailFella → click the pin. It'll always be one click away.
Step 2 — Connect it to your account
Once installed, click the extension icon and enter your MailFella account email. This tells the extension where to save the addresses you collect.
Then choose or create a category for your emails. Categories keep your list organized so you can send targeted campaigns later — for example, sending a different message to restaurants than to plumbers.
Restaurants – Helsinki
Plumbers – Stockholm
Hair Salons – London
Dentists – Berlin
Real Estate – Madrid
Accountants – Dublin
Think ahead: Create specific categories rather than a big generic list. "Restaurants – Helsinki" will always outperform "Everyone" when you send a campaign.
Step 3 — Start collecting
Browse any website that shows email addresses — business directories, company contact pages, local listing sites. When you see an email you want to save, right-click it and choose Collect Email from the menu. It's instantly saved to your MailFella account.
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Business directories
Yellow Pages, Yelp, local city directories — all great sources for B2B emails organized by category.
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Company websites
Contact pages and About pages often list direct email addresses for the right person.
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Industry-specific sites
Restaurant booking sites, trade directories, local chamber of commerce listings — wherever your target businesses appear online.
Quality over quantity: 50 relevant emails beat 500 random ones. A restaurant owner will respond to an email about restaurant software — they'll ignore one about office supplies.
Legal considerations
Collecting publicly visible business email addresses is generally acceptable for B2B outreach in most countries. That said, a few rules apply everywhere:
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Always include an unsubscribe link
MailFella templates include this by default. Required under CAN-SPAM, GDPR, and most other laws.
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Only collect publicly available addresses
If an email is visible on a public webpage, it's fair game. Don't scrape members-only or login-gated content.
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Be relevant
Sending relevant, professional emails to businesses is outreach. Sending irrelevant bulk mail to anyone you can find is spam. The difference is intent and relevance.
Common questions
Is it legal to collect emails this way?
Collecting publicly available business emails for B2B outreach is generally legal in most countries. You must always include an unsubscribe option and honor opt-out requests. For personal (non-business) emails, rules are stricter — GDPR in particular requires consent. When in doubt, stick to business addresses.
How many emails should I collect per week?
Focus on quality over speed. 20–50 well-targeted emails per week is a healthy pace. A focused list of 100 relevant contacts will outperform a scattered list of 1,000 every time.
What browsers does the extension support?
Currently Google Chrome and Chromium-based browsers (Edge, Brave). Firefox support is planned.
Can I import an existing email list?
Yes. If you already have a list in a spreadsheet or CSV file, you can import it directly into your MailFella account without using the extension at all.