Browse by...
Home Resources Blog

Our design and spam testing tool has been a super popular feature since we launched it a year or so back. For many of you it’s a crucial part of the design process for each campaign you send. Because of this, it can get frustrating when that key email client isn’t returning any results. We’ve been working hard to make this a thing of the past, and I think you’ll like what we’ve come up with.

First, a bit of background


Building a service to generate screenshots in dozens of different email clients is a huge undertaking. We looked at our options, and after trying out a few services we partnered with the great folks at Return Path, the biggest provider in the industry (who do lots of other great stuff too).

Since that time, tens of thousands of spam tests have been run with thousands more added every month. As I said, a service like this is a challenge to maintain, so it’s not surprising that some email clients can take longer than others to return results. Unfortunately at times this can lead to a frustrating experience for our customers. When you’re working on a time sensitive campaign and need to see how it looks in Outlook 2007, you want that screenshot back in minutes, not hours or days. We understand that.

As the middle man in all this, it’s been a challenging time for us too. We know the Return Path guys are working incredibly hard to ensure they are always returning all screenshots in a timely manner. We know you need your screenshots returned in a timely manner. This got us thinking hard about what we can do as the middle man to make sure you get the best testing experience possible.

What about Litmus?


We’ve been big fans of the Litmus team for some time now. Their email testing service has come a long way in the last 12 months as they continue to add more email clients and spam testing services to their roster. We’ve been watching their service closely and were impressed with what we saw.

The initial plan was to try their service out internally and see if it was a viable alternative to Return Path. Every time you guys ran a design and spam test, we submitted it to both providers to see which one consistently returned the best results. In the end, it turned out there was no real winner. Return Path were quicker for some email clients, while Litmus was faster for others. We were left with a difficult choice.

That was, until Ben, our lead developer and co-founder asked the obvious question: “Why don’t we just use both services simultaneously?”

When two become one

In hindsight it seems crazy we didn’t think of this first, but by combining both providers into a single service for our customers, we can instantly provide the fastest, most reliable design and spam testing tool on the market today.

Every time you run a test, we fire off your campaign to both providers simultaneously and sit back to see which one returns each screenshot first. It’s like horse racing for nerds. Whichever one returns that screenshot or spam filter result first is displayed in your account. The beautiful part about this approach is the reliability side of things. There’s only a slim chance that both providers will have rendering problems with a specific email client at the same time. So, if Litmus isn’t returning Lotus Notes 6.5.4 right now, there’s a good chance that Return Path will be.

What about the cost?

This one wasn’t an easy choice. Obviously our costs for providing this service have just doubled. A number of other email marketing apps also integrate with Return Path, only they charge at least two or three times our current price. We had some room to move, but in the end decided that we weren’t comfortable passing this on to our customers. You guys shouldn’t have to pay more for a service that works like it always should have.

The test price is exactly the same as it always was, and we’re happy to lose our profit for the sake of a much better experience. Unfortunately, due to pressure from others providing similar services, we can’t share our prices here. If you log into your account, you’ll see they’re just as low as they’ve always been.

No more surprises

Even though we’ve merged the two providers into a single service, every so often both might be having trouble with a particular client. There’s nothing worse than paying for a test to see your email in a particular client, and that’s the one email client that isn’t returning results. We’ve put an end to that issue too.


Each time you run a test, we’ll provide a clear warning like the one above about any particular email client that’s been returning poorly across both providers. This way, you’ll know exactly what you’ll be getting for every test you run. Of course, if the key client you’re looking for isn’t available this isn’t much help, but at the very least we won’t be wasting your time and money.

New email clients and spam filters

By merging Litmus into our testing suite, we’ve also added some useful new email environments. Our Windows customers will be loving the addition of the two most recent versions of Apple Mail. We’ve also broadened our Lotus Notes support with the latest two versions, meaning we now cover all major releases from version 6.5.4 through to 8. Here are the additions:

  • Apple Mail 2.1
  • Apple Mail 3
  • Lotus Notes 7
  • Lotus Notes 8
  • Outlook 2000

Litmus also supports a number of new spam filters that we’ll also be running every test through, including popular web-based email providers like Yahoo! Mail and Gmail. Here’s the list of new filters now available.

  • AOL
  • Gmail
  • Hotmail
  • Outlook 2007
  • Yahoo!

We’re not stopping there

Now that we’ve got the biggest feature on the list done – reliability, we can get started on other cool ideas we’ve got cooking to make designing and testing your emails as pain free as possible. A big thanks to the team at Return Path and Litmus for all their help and patience as we worked hard to bring this all together. We think it was worth it, and hope you do too.

This blog provides general information and discussion about email marketing and related subjects. The content provided in this blog ("Content”), should not be construed as and is not intended to constitute financial, legal or tax advice. You should seek the advice of professionals prior to acting upon any information contained in the Content. All Content is provided strictly “as is” and we make no warranty or representation of any kind regarding the Content.
Straight to your inbox

Get the best email and digital marketing content delivered.

Join 250,000 in-the-know marketers and get the latest marketing tips, tactics, and news right in your inbox.


Get started with Campaign Monitor today.

With our powerful yet easy-to-use tools, it's never been easier to make an impact with email marketing.

Try it for free