Email marketing consistently delivers the highest ROI of any digital channel — roughly $36 back for every $1 spent, according to industry benchmarks. But there is a massive difference between running a bulk email campaign the right way and turning your brand into spam. The line between them is one word: consent.
This guide walks you through how bulk email works, when to use it, how to build a permission-based list, how to stay out of the spam folder, and how to use Code2Scan's Email Blaster to send campaigns like a pro.
What is bulk email and when does it make sense
Bulk email (also called mass email or email marketing) means sending the same message — or personalised variations — to a list of subscribers at once. Legitimate, effective use cases:
- Re-engaging inactive customers: "We miss you — here's a discount".
- Announcing new products or services: launches, updates, feature releases.
- Promotions and sales: Black Friday, seasonal events, clearance.
- Newsletter: regular content that keeps your audience engaged.
- Operational updates: schedule changes, policy updates, maintenance notices.
What bulk email is NOT: sending messages to people who never asked to hear from you. That is spam — and it costs you in reputation, deliverability, and potential legal fines.
The golden rule: only send to people who opted in
Privacy regulations (GDPR in Europe, CAN-SPAM in the US, and equivalents worldwide) require a legal basis for processing personal data. In email marketing, that basis is usually consent: the person explicitly chose to receive your emails.
What opt-in means
Opt-in means the contact took an active step to join your list:
- Filled in a sign-up form
- Checked a box saying "I want to receive updates by email"
- Made a purchase and agreed to marketing communications
Double opt-in goes further: after signing up, the contact receives a confirmation email and must click to verify. It is the safest approach — it confirms the address is real and belongs to the person who signed up.
What to never do
- Buy email lists: illegal under most privacy laws and ineffective (those contacts never asked to hear from you; spam complaints will skyrocket).
- Scrape emails from websites or social media: same problem.
- Add customers without explicit consent: having someone's email for a transaction does not mean you can send them marketing.
How to capture emails with consent (including with QR Codes)
The most effective way to grow a healthy list is to offer something of value in return for the sign-up: a discount, a free guide, early access, exclusive content. Proven tactics:
- Sign-up form on your website: landing page or pop-up with an email field.
- QR Code to a form: print a QR Code on menus, flyers, packaging, or your shop window. The customer scans and lands straight on your sign-up form. See QR Code for Google Forms for a quick setup.
- Email signature form link: add a QR Code or link in your email signature so new contacts can subscribe.
- Link in bio: if you use social media, a link in bio can consolidate all your sign-up pages in one place.
Best practices vs. mistakes that trigger spam filters
| Best practice | Mistake that lands you in spam |
|---|---|
| Send only to opted-in contacts | Buy or scrape lists |
| Honest, descriptive subject line | Clickbait or misleading subject |
| Clear sender name and address | Generic or unknown sender |
| Visible unsubscribe link in every email | Hiding or burying the unsubscribe option |
| Warm up your domain gradually | Sending 50,000 emails on day one |
| Clean bounces and inactive contacts regularly | Keeping invalid addresses on the list |
| Authenticate your domain (SPF, DKIM, DMARC) | Sending without domain authentication |
| Predictable, respectful send frequency | Flooding inboxes every single day |
Step-by-step: set up your first campaign
1. Build (or import) your opt-in list
Only include contacts who gave explicit consent. If you have an existing customer list, check whether you have a documented consent record for marketing communications.
2. Authenticate your domain
Set up SPF, DKIM, and DMARC records in your domain's DNS. This proves to receiving mail servers that you are who you say you are — and dramatically reduces the chance of hitting the spam folder.
3. Warm up your domain
If the domain is new to bulk sending, start small:
- Week 1: 200–500 emails/day
- Week 2: 1,000–2,000/day
- Week 3 onwards: gradual increase
Sending high volume from a cold domain destroys its reputation immediately.
4. Write the email
- Subject line: short (40–50 characters), honest, sparks curiosity without clickbait.
- Preview text: the snippet shown after the subject in mobile inboxes — use it.
- Body: focused, with a single clear call to action.
- Footer: your name/company, physical address, unsubscribe link.
5. Send with Code2Scan's Email Blaster
The Email Blaster is Code2Scan's bulk sending add-on. With it you can:
- Import or manage your contact list
- Create emails with a visual editor or raw HTML
- Schedule or send immediately
- Track open rates, clicks, and bounces in real time
6. Measure and optimise
Add UTM parameters to the links inside your emails to track traffic in Google Analytics. The same UTM logic used for QR Codes applies here — see the trackable QR Code with UTM guide.
Monitor:
- Open rate: 20–30% is a healthy benchmark
- Click-through rate (CTR): 2–5% is solid for most niches
- Unsubscribes: above 0.5% per send, review your content or frequency
- Bounce rate: above 2%, clean your list
Common mistakes
❌ Misleading subject lines
"You just won $500!" when they didn't — destroys trust and spikes spam complaints.
❌ No unsubscribe link
Required by law in most jurisdictions. Making it hard to opt out is worse than losing a subscriber: the person will mark you as spam, which harms your domain reputation for everyone else on your list.
❌ Purchased lists
Beyond being illegal, they simply don't work: near-zero open rates, massive bounce rates, risk of hitting spam traps and getting your domain blacklisted by Gmail, Outlook, and Yahoo.
❌ Sending without domain authentication
Without SPF/DKIM/DMARC, Gmail and Outlook will route your emails straight to spam — or reject them outright at the server level.
❌ Ignoring mobile
Over 60% of emails are opened on mobile devices. A non-responsive template means a bad experience and higher unsubscribe rates.
Summary
- Only email people who opted in — never buy a list.
- Authenticate your domain (SPF, DKIM, DMARC) before the first send.
- Warm up a new domain gradually.
- Honest subject line, identified sender, visible unsubscribe link.
- Track everything: opens, clicks, bounces, unsubscribes.
- Use a professional tool to manage your list and sends.
Ready to send the right way? Code2Scan's Email Blaster is the add-on that connects your opt-in contacts to professional campaigns — with real-time analytics, a visual editor, and list management built in. Get started today.
