Email lists and consent management
Effective email delivery begins with maintaining clean, permission-based contact lists. Infobip provides tools and recommendations for managing subscribers, suppressions, and compliance in line with industry standards.
Email lists
Email lists are the foundation of your sending strategy. A high-quality list consists of valid, opted-in recipients who are actively engaged with your communication. Build your lists through transparent sign-up forms and verified sources. Avoid using purchased or scraped lists, as these often contain invalid or unengaged addresses, which can damage your sender reputation and reduce deliverability.
Regularly audit your lists to remove inactive users, duplicates, or addresses with a history of bouncing. If a recipient has not interacted with your emails for an extended period, consider a re-engagement campaign. If there is still no response, remove them from your list.
Subscriber preferences
Respecting subscriber preferences is key to fostering trust and maximizing engagement. Infobip allows you to personalize messages using attributes and preferences collected during the sign-up process, such as content preferences, communication frequency, and channel choices.
To comply with regulations and ensure strong deliverability, always include an unsubscribe link in your email campaigns. Internet service providers require email service providers to:
- Automatically handle unsubscribe requests
- Track and manage bounce rates
- Monitor abuse reports via ISP feedback loops
High unsubscribe or complaint rates can negatively affect your sender reputation and email deliverability. Maintaining clean and permission-based contact lists helps protect your account and ensures your messages continue reaching the inbox.
Blocklist
Blocklist configuration allows you to define how unsubscribes are handled, either at the domain level or the individual sender address level.
When a user unsubscribes, they usually want to stop receiving all emails from your brand, not just a specific campaign. Managing unsubscribes at the domain level helps you:
- Align with user expectations
- Reduce spam complaints
- Improve deliverability
- Maintain compliance
- Strengthen brand trust
Blocklist options
| Option | Description |
|---|---|
| From sender address | Removes the recipient only from the specific sender address (for example, [email protected]). They may still receive messages from other addresses under the same domain. |
| From this domain | Globally unsubscribes the recipient from all communications sent from the domain, ensuring complete opt-out from your brand. |
Read more about Domain configuration.
Suppression lists
Suppression lists store contacts who should not receive emails, either due to previous bounces, complaints, or manual unsubscribes. Addresses are automatically added to the suppression list when hard bounces or spam complaints occur.
By preventing messages from being sent to these recipients, suppression lists help you:
- Maintain a strong sender reputation
- Reduce bounce and complaint rates
- Avoid spam filters
- Focus on reaching engaged, relevant audiences
You can manage your suppression lists programmatically using different Email suppression API endpoints (opens in a new tab), making it easy to upload or delete bounces and complaints. Keeping your lists up to date ensures cleaner campaigns and better inbox placement.
Learn more about Suppression management.
Feedback loops
Feedback loops (FBLs) allow mailbox providers to notify Infobip when a recipient marks an email as spam. These notifications are used to automatically suppress the recipient and prevent further deliveries. When a recipient marks your email as spam, it signals non-compliant behavior and negatively affects your sender reputation.
By subscribing to feedback loops, you gain visibility into spam complaints and can take corrective actions, such as removing the complaining recipients from your list.
Use feedback loops to:
- Keep your subscriber lists clean
- Identify issues with sending frequency, content, or targeting
- Maintain compliance and improve deliverability
Infobip integrates with supported mailbox providers to receive and process FBL data in real time. This ensures spam complaints are immediately reflected in your suppression lists, helping you reduce complaint rates and protect your IP reputation.
Email housekeeping
Good data hygiene is essential to email program health. Housekeeping includes regularly removing invalid, inactive, or unengaged contacts, updating user preferences, and archiving outdated segments.
Crafting clear subject lines and well-curated content helps your emails stand out in crowded inboxes and pass through spam filters successfully.
Spam filters evaluate several elements of your email, including:
- Subject line and preheader text
- Body content
- HTML structure and formatting
- Presence of unsupported code (such as scripts or forms)
- Embedded images and overall design quality
Spam filters also scan for suspicious keywords and formatting issues. Run a spam check before sending your campaign.
Common content triggers for spam filters
Avoid the following to increase your chances of landing in the inbox:
- Writing your entire email in all caps
- Random or frequent capitalization
- Excessive punctuation, especially "$" and "!"
- Strange spacing or too much blank space
- Spelling errors
- Inconsistent font sizes and text colors
- Scam-like subject lines
High-risk words and phrases include:
- Eliminate your debt
- Risk-free
- FREE!!!
- 100%, 4U, Best price, Lowest price
- Extra cash, Amazing, Fantastic, Score
- For you, Now only, Call now
- Giveaway, Offer, Trial, Unlimited, Urgent
By keeping your content clear, relevant, and well-formatted, you will avoid spam filters and increase the chances of your message reaching engaged readers.
Email compliance
Email communications must comply with local and international regulations such as GDPR, CAN-SPAM, and CASL. Infobip supports compliance through domain verification, automated unsubscribes, and suppression list enforcement.
To stay compliant and build trust:
- Obtain clear opt-in consent from recipients and store proof where needed.
- Include a visible, functional unsubscribe link in every message. Per the CAN-SPAM Act, opt-out requests must be honored within 10 business days.
- Use confirmed opt-in (double opt-in) for better engagement and sender reputation.
Email opt-in laws
- USA - CAN-SPAM Act (opens in a new tab)
- Canada and Australia - CASL (opens in a new tab)
- European Union - GDPR (opens in a new tab)
To ensure compliance and trust, always provide clear opt-in options and a way for users to easily manage their preferences.