Keeping email lists clean is essential for successful recruitment campaigns in Fuel Cycle. Fuel Cycle uses IPQualityScore (IPQS) to evaluate email addresses before sending mass emails, filtering out those with medium or low deliverability to protect sender reputation and minimize bounce rates. Suppressed addresses are not necessarily invalid, but are unlikely to reach inboxes via Fuel Cycle. Users can access suppressed addresses for CRM updates, but cannot send to them through Fuel Cycle, ensuring higher inbox placement and domain protection.
What Deliverability Means
When sending mass emails, the goal is to reach inboxes, not bounce or get caught in spam filters. Even if a domain isn’t “bad,” risky or inactive email addresses can harm a sender’s reputation over time. A high bounce rate makes it more likely that mailbox providers (like Gmail or Yahoo) will filter or block future messages.
How Fuel Cycle Uses IPQualityScore (IPQS)
To protect deliverability, Fuel Cycle uses IPQualityScore (IPQS) to evaluate every email address before sending. IPQS runs real-time checks against signals such as:
- Invalid or inactive domains
- Spam traps
- Abuse or bounce history
- Disposable email services
- Other risk factors
Why Some Addresses Are Suppressed
Based on IPQS scoring, addresses marked medium or low deliverability are suppressed from Comm Center sends. While the full scoring logic is proprietary, this filtering:
- Protects your domain reputation
- Minimizes bounce rates
- Ensures higher deliverability for valid addresses
Note: A suppressed address does not mean fraud or invalidity — only that inbox providers are unlikely to accept messages sent from our platform.
What This Means for Your List
We understand many suppressed addresses belong to real people you want to reach. If your goal is list maintenance, we can provide the suppressed addresses so you can update or remove them in your CRM. However, we cannot send to those addresses from within Fuel Cycle, as doing so would undermine deliverability safeguards.
Ongoing Evaluation
Our product team continually monitors deliverability trends and mailbox provider requirements. As standards evolve, our thresholds may change. For now, sending only to high-deliverability addresses ensures the best inbox placement and protects your community’s sending domain.
Alternative Options
You may choose to manage outreach to suppressed addresses using your own sending infrastructure outside of Fuel Cycle. If you do, we recommend caution, as the same deliverability risks still apply.