What Is the Spamhaus Blacklist and What Does It Do to Your Email Deliverability?
Spamhaus can kill your email deliverability overnight. Warmy's 2026 research breaks down every list, what triggers them, and…
Email Best Practices
SURBL Blacklist: What Is It, Why You Get Listed, and How to Fix It
This SURBL blacklist report by Warmy.io discusses what triggers a SURBL listing, how to check your domain, and…
The Barracuda Reputation Block List: What Every B2B Email Sender Must Know
The Warmy Research Team breaks down how the Barracuda Reputation Block List works, what triggers an IP listing,…
Does Email Batch Size Matter? A Year of Deliverability Data Has The Answer
Email deliverability conversations often focus on what you send: subject lines, copy, personalization, authentication. Far less attention is…
SMTP vs API Sending: One Year of Google Sending Data
If you work with email at any meaningful scale, the question inevitably comes up: is it better to…
Black Friday Deliverability Horrors: Turn Chaos Into Success
Every year, Black Friday evolves into more than just a single day of shopping frenzy. It has become…
Warm Up vs Warm Up With Clicks: What 2025 Data Reveals About Real Inbox Gains
Email deliverability in 2025 is not just shaped by technical setup alone. As algorithms continue to evolve, mailbox…
Cracking the Code: Why Emails Land in Gmail's Promotions Tab
Once upon a time, Gmail’s inboxes were a mishmash of personal emails, work emails, transactional emails and so…
The Fastest Path to Yahoo Inboxes: Analyzing SMTP Providers
With around 230 million active users and a significant share of the email market, Yahoo Mail is definitely…
Impact of Tracking Links and Images on Gmail Deliverability
In cold email outreach campaigns, deliverability is a legit concern. And even after you draft the perfect email,…
Signature Showdown: Crafting the Perfect Email Signature
In a world where email marketers compete for open rates, click-through rates, and conversions, the email signature may…
What Speeds Up Outlook Delivery from Different SMTP Providers?
If you’ve ever wondered why some domains warm up faster than others, you’re not alone. For marketers and…
