Why did UCEPROTECT listings drop for SparkPost and Sendgrid?
Michael Ko
Co-founder & CEO, Suped
Published 7 Aug 2025
Updated 15 Aug 2025
8 min read
Recently, there's been some discussion about UCEPROTECT listings, specifically how they seem to have dropped for major email service providers like SparkPost and SendGrid. This can be a bit confusing, especially when you're used to seeing these providers frequently appear on UCEPROTECT's various levels. For many, a sudden change like this might prompt questions about deliverability and the overall health of their sending infrastructure. Understanding why these changes occur requires a closer look at UCEPROTECT's methodology and its standing within the broader email community.
It's important to remember that not all blocklists (or blacklists, as they are often called) carry the same weight. While some, like Spamhaus, are widely respected and can significantly impact email delivery, others have a questionable reputation. UCEPROTECT falls into the latter category for many email professionals.
The core of the issue often isn't the listing itself, but the alarm it triggers for email senders who rely on blocklist monitoring tools. We've seen clients panic simply because they received an alert, even when the actual impact on their email traffic was negligible.
UCEPROTECT operates on a multi-tiered system, with Level 1 focusing on individual IPs, Level 2 on subnets, and Level 3 on entire Autonomous System Numbers (ASNs). Their listing policies have historically been very aggressive, often leading to large-scale blocklisting (or blacklisting) that can affect many users on a shared infrastructure, such as those provided by major email sending services.
For instance, their Level 3 (L3) policy has been particularly controversial. It has been known to list an entire ASN if a very small percentage of its IPs are listed on Level 1. There were reports of them changing this threshold, which could directly affect the presence of large ESPs on their lists. This kind of dynamic policy can lead to sudden fluctuations in listings, even without a significant change in the ESP's sending practices. This is one of the reasons why the overall email community often views UCEPROTECT with skepticism, questioning its legitimacy as a reliable anti-spam measure.
Another factor that influences UCEPROTECT listings is an automatic timeout. Many blocklists operate on a system where listings expire after a certain period if the offending activity ceases. This means that even without any specific action from the listed entity, an IP or ASN might automatically be removed from the list after a set duration. If SparkPost or SendGrid IPs had been listed for some time, they could simply have timed out of the system.
Here is an example of what a typical blocklist entry might look like (illustrative purposes only):
Example UCEPROTECT listing format
192.0.2.1 ; LISTED: UCEPROTECT-L3 (ASN12345) - too many Level 1 listings. See http://www.uceprotect.net/en/index.php?m=12&s=0
The 'pay to delist' dilemma and community consensus
One of the most criticized aspects of UCEPROTECT is its reputation for offering paid delistings. This practice, often referred to as an extortion racket, means that an entity can pay a fee to be removed from the blocklist. This model fundamentally undermines the credibility of any anti-spam service, as it suggests that listings are not solely based on spamming activity but can be influenced by payment.
Major email service providers like SparkPost and SendGrid have publicly stated that they do not consider UCEPROTECT a legitimate blocklist and therefore do not pay for delistings. This stance is crucial, as paying would set a precedent that acknowledges UCEPROTECT's dubious practices. Furthermore, even if an organization were to pay, UCEPROTECT openly states that the delisting is only temporary and does not prevent re-listing if spam trap hits continue. This means paying would be a futile exercise for an ESP sending large volumes of mail.
The broader email community, including those who manage and operate other reputable blocklists, has even gone so far as to write RFCs (Requests For Comments) to highlight UCEPROTECT's questionable practices. This collective dismissal by industry experts strongly indicates that UCEPROTECT's influence on actual email deliverability to major inbox providers is minimal to non-existent. For more details on how to handle such listings, explore our guide on dealing with UCEPROTECT listings.
The problematic delisting model
UCEPROTECT's business model relies on charging for delisting. This practice is widely condemned by the email deliverability community as it incentivizes arbitrary listings rather than genuine anti-spam efforts. Paying does not resolve the root cause of any spam issues.
Actual impact on email deliverability
Despite the alarms that UCEPROTECT listings might trigger, the general consensus among email deliverability professionals is that they have little to no actual impact on email deliverability to major ISPs, such as Google and Microsoft Outlook. These major mail providers rely on their own sophisticated internal filtering systems, which are informed by a multitude of factors, not just third-party blocklists (or blacklists) like UCEPROTECT.
The primary concern for many email senders, especially those using shared IP pools from ESPs, is not the actual email rejection rate but the psychological impact of seeing a listing. As one user noted on Hacker News, the main problem is the alerts customers receive from their own blocklist monitoring tools, causing undue panic without understanding the actual deliverability impact. For more insight into blocklists, refer to our comprehensive article, The difference between a blacklist and a blocklist.
Essentially, for major ESPs like SparkPost and SendGrid, their internal reputation management and adherence to best practices for high-volume sending are far more critical than any UCEPROTECT listing. The fact that their listings dropped likely reflects either an internal policy adjustment by UCEPROTECT or simply the natural expiry of listings, rather than a direct action or payment from the ESPs themselves.
UCEPROTECT blocklist
Impact on deliverability: Generally considered minimal or negligible by major ISPs.
Listing criteria: Aggressive, can include large ASNs based on a small percentage of listed IPs.
Delisting process: Offers paid delisting, which is controversial and temporary.
Major blocklists (e.g., Spamhaus)
Impact on deliverability: Significant and widely adopted by most mail providers globally.
Listing criteria: Strict, based on confirmed spam, botnet activity, or known bad actors.
Delisting process: Typically requires investigation, remediation of the spam source, and formal request, with no payment involved.
Possible reasons for the listing drop
The drop in UCEPROTECT listings for SparkPost and SendGrid is most likely attributable to a combination of factors, none of which necessarily indicate a change in the ESPs' core deliverability practices. It's more probable that UCEPROTECT adjusted its internal algorithms, perhaps returning to an older, less aggressive listing policy for Level 3 ASNs. This could have automatically removed many large networks that were previously caught by the stricter criteria.
Additionally, the nature of many blacklists (or blocklists) includes automatic timeouts. If an IP or ASN ceases to exhibit the behavior that led to its listing, it will often be automatically removed after a set period. Given that major ESPs like SparkPost and SendGrid are constantly working to maintain high deliverability, it's plausible that some of their IPs simply aged off the UCEPROTECT lists.
Ultimately, for email marketers and businesses using these platforms, UCEPROTECT listings should not be a primary concern for their email deliverability. Focusing on robust authentication, maintaining a clean mailing list, and monitoring legitimate feedback loops from major ISPs will yield far greater returns for inbox placement.
Views from the trenches
Best practices
Monitor your email deliverability metrics through Postmaster Tools from major providers like Google and Outlook, as these offer more reliable indicators of your sending reputation.
Prioritize maintaining a clean email list by regularly removing inactive subscribers and implementing confirmed opt-in processes to prevent spam trap hits.
Ensure proper email authentication protocols (SPF, DKIM, DMARC) are correctly configured and aligned, as these are critical for gaining trust with inbox providers.
Common pitfalls
Panicking over UCEPROTECT listings; their impact on actual deliverability to major ISPs is minimal and often not worth the concern.
Considering paying UCEPROTECT for delisting, as this only provides temporary relief and does not address underlying deliverability issues.
Relying solely on external blacklist checkers without understanding the true influence of each blocklist on recipient inboxes.
Expert tips
Understand that UCEPROTECT's algorithms for Level 3 listings can be highly aggressive and may capture large, legitimate networks based on disproportionately small issues.
Remember that many blocklists, including UCEPROTECT, have automatic timeout mechanisms that can remove listings after a period of inactivity or improved behavior.
Educate your team and clients about the varying credibility of different blocklists to prevent unnecessary alarm when non-impactful listings occur.
Marketer view
Marketer from Email Geeks says they saw all their SendGrid IPs were no longer showing UCEPROTECT listings, but noted that UCEPROTECT's pay-to-delist practices are not to be taken seriously.
2021-02-02 - Email Geeks
Expert view
Expert from Email Geeks says that listings appear and disappear, but rejections remain consistently flat, indicating little real-world impact from UCEPROTECT.
2021-02-02 - Email Geeks
Key takeaways
The observed drop in UCEPROTECT listings for SparkPost and SendGrid is a reflection of UCEPROTECT's volatile listing policies and its limited influence on the broader email ecosystem. It is highly unlikely that these major ESPs paid for delisting, given their public stance and the ineffectiveness of such payments. Instead, the changes are probably due to internal policy adjustments by UCEPROTECT or the natural expiry of listings through their automated timeout system.
For email senders, this event serves as a reminder to prioritize reputable sources for deliverability monitoring and to not overreact to listings on blocklists with questionable efficacy. Your efforts are best spent on adhering to email sending best practices, maintaining a healthy sender reputation, and ensuring proper email authentication. These are the true determinants of getting your emails to the inbox.
Spamhaus
0Spam
Cisco
NoSolicitado
URIBL
abuse.ro
ALPHANET
Anonmails
Ascams
BLOCKEDSERVERS
Calivent Networks
EFnet
JustSpam
Kempt.net
NordSpam
RV-SOFT Technology
Scientific Spam
Spamikaze
SpamRATS
SPFBL
Suomispam
System 5 Hosting
Team Cymru
Validity
www.blocklist.de Fail2Ban-Reporting Service
ZapBL
2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheft
Google and 
Microsoft Outlook. These major mail providers rely on their own sophisticated internal filtering systems, which are informed by a multitude of factors, not just third-party blocklists (or blacklists) like UCEPROTECT.
