A few weeks ago we released a free API for checking the spamscore of a message. The folks on HackerNews loved it, and it’s been really great to see people find ways to get more value from this API.

Some of our favorite usages have shown up in just the last week!

Spamscore.me

We released our Spam Checking API with an easy and beautiful UI, but it does require that you grab the full email contents including the headers. Simple as this is, it’s work. Wouldn’t it be great if you could just forward an email somewhere, and moments later, get back a nicely formatted report about your email’s spamscore?

That’s exactly what Jim Carter built with spamscore.me. The cool thing about spamscore.me is there’s no interface other than your email client! Just forward any email to go@spamscore.me and get one of these bad boys back.

It’s free (but no less awesome), so please be kind to Jim’s servers. Have other ideas for useful mashups with our spamscore API? Let us know in the comments, or better yet email me once you’ve launched so we can write about it here!

Christmas is saved on Reddit

Our hearts were warmed to find that someone recommended our spamscore checker to a Reddit user whose christmas eCards were being sent to spam. 

Chris was able to jump in and do a quick analysis of the person’s spamscore report, recommending the following to help with the resolution:

• Set your Return-Path header to a domain and address that you control. Then, add an SPF record to that domain with the permitted SMTP servers.
• Do not use your user’s email as the from address. This is spoofing and you can’t control the DKIM or SPF. Instead, use their “From name” but your email address.
• Make sure Reverse DNS is setup for your SMTP server.

While we can’t promise personal spamscore report interpretation for every problem, we’re thrilled to see that this tool is being used to help solve real world problems in people’s applications.

Have you used the spamscore API to successfully track down a problem? Let us know in the comments.

Postmark’s sending infrastructure works to carefully, quickly, and accurately deliver your transactional emails to your customers’ inboxes. The most common problems that occur outside of our configurations are related to content, and our customer service team often works with customers to improve dodgy email content that’s causing emails to land in the spam filter.

Today we’re announcing a new easy and free API to help you score the quality of your outbound (and inbound) emails. This JSON API provides easy and fast programmatic usage of the spam filter tool SpamAssassin.

Simply POST an email’s contents, all headers included, against our API and we’ll return a score. If you want, we can also return a full report in your call.

Not API savvy? No problem! Our landing page for the API provides a fully functional scoring & reporting tool for you without having to ever write a line of code.

Write an API wrapper, Get Free Postmark Credits

This API is silly-simple, but we want to make sure that it’s useful. One way to do that is to make sure that there’s a simple interface to it in everyone’s favorite programming languages & frameworks. 

We’ll give 10,000 free Postmark credits to the first person to write and open source a complete API wrapper for our Spam Score API in a given language/framework. We’ll compile a directory of the wrappers and publish them along with the API.

Our own Oren Mazor (who wrote the API) has provided an example library in Python, if you’re looking for patterns to follow. 

To submit an API wrapper, email a link to your repository to alex@wildbit.com. We’ll provide the free Postmark credits to one winner per language/framework, based on the timestamp of the submission. 

HackerNews Discussion

We “soft” released this on Friday night and there was some great discussion on HackerNews, spending most of the weekend on the home page. Jump over to the comments thread to see what people think!

Last week we were troubleshooting a problem with a customer. For some reason, no matter what we tried, their emails were going directly to the spam folder in Yahoo. I tried replicating the email, from name, subject and everything else but each time it went to the Inbox. After lots of tests, we identified one difference: An image url in the email referenced the cloudfront.net CDN domain from Amazon Web Services. After we moved the image to their own domain, it went right to the inbox.

So, what does this mean?

The issue is nothing new. When it comes to publicly used domains, there is a high chance of spammers also using these domains, which can end up on uri blacklists. Similar problems have happened with Bit.ly and Tinyurl. The usual troubleshooting is to head over to sites like SURBL and URIBL to check if the domain is listed. In this case however, cloudfront.net is no where to be found. It seems that Yahoo has some of their own internal rules for this domain.

How to prevent this from happening

If you use CDN services (like Coundfront) or URL shortener services (like bit.ly) we recommend creating CNAME records so you can use your own domain. Bit.ly also offers a Pro service where you can use your own domain. By using your own domain, you can control your own reputation when it comes to blacklists (if it is domain based). Of course, if you act like a spammer, you’ll most likely end up on those lists as well.

Has anyone else noticed issues with Cloudfront? I’m interested to hear other examples so we can help other customers with delivery.

I’m often reading emails from customers asking the same question: Why can you get my email to the inbox when I keep sending it to Spam. Well…because we’ve paid off the ISPs and they let us get right through (not, we wish). The true answer is complicated, but I’ll try to explain the various moving pieces here.