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How blacklists don’t work

Oh, how I love tossing an IP into multirbl.valli.org, a true one-stop-shop to instantly check “all the things.” But I also see a lot of people freak out when they see the results realizing, “My IP is blacklisted!!!”

At this point, I usually step away from my laptop, grab a cup of tea, listen to a clip of the ocean, and ask my sister to text me the story about a kid who knocked her glasses off in gym class resulting in a seemingly endless “Velma Moment.”

That’s because there’s just so many blacklists in existence, primarily because there are no requirements to start one. Anyone with a computer connected to the internet can create a public blacklist, and as a result, not all of them are useful or apply to the messages you send.

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My file is not small, it’s fun-sized!

Your message file size matters. Some may think it’s great to send a ton of content in one fell swoop, but most ESPs limit the size of the message you can send through their service. That’s likely because they’re sending bulk messages, so they have to keep an eye on the processing power and time it takes to send a lot of very large messages at once.

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Feature announcement: more useful weekly account digests

We know from our open rates and follow-up questions that users rely heavily on the information in the email we send every Monday morning with statistics of selected servers. This weekly digest emails have always been useful, but we knew they could be better. So starting next week, you’ll see a new design and some additional information to help you manage your account better.

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Filtering changes at Gmail

In the past couple of weeks, we’ve seen multiple customers report that their messages to Gmail/GSuite recipients are suddenly delayed, ending up in the spam folder, or just missing entirely.

Google publicly confirms they've made widespread changes to substantially increase spam blocking, which were rolled out at the end of January. I've been personally tracking and testing these cases affected by the changes, and here’s what I know so far.

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How to send and track the status of email using Python and the Postmark API

Like many cloud developers, I have been creating several new apps using Python. The beauty of Python is in its visual simplicity and the many powerful libraries that abstract essential functions like JSON encoding and sending HTTP requests. Postmark's API allows us to send emails with very few lines of code, and it also allows us to track the status of those email operations. In this blog post, I'll be showing the steps to take to get that going.

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