Task Monitoring Using Redis

We’ve started using Redis a lot and it’s been great. We’ve already used it to improve performance in our analytics pipeline, and to power our usage-based billing system.

Most recently we’ve written a leaner, faster version of our background task monitoring system based on Redis. Here’s how we did it…


Digging Into Data From 50M Transactional Emails


As part of our ongoing mission to help everyone send better emails, we recently took a random (and anonymous) sample of 50,000,000 transactional emails sent through Sendwithus and began to investigate the data.

To start, we wanted to classify the purpose and intent of every email. We devised a hacky (and unimaginative) algorithm to sort each email into one of nine categories…


Python Templating Performance Showdown: Django vs Jinja

A few weeks ago, we announced that we would be upgrading our templating language from Django to Jinja and discussed some of the reasons for doing so. At the time we promised a follow-up with more depth on the technical details. Today we’re here to fulfill that promise.

As mentioned previously, the three big reasons we’re upgrading to Jinja are that it’s highly extensible, fast, and easy to sandbox. We also considered Genshi and Mako, but eventually landed on Jinja because, in addition to fulfilling our criteria, Jinja had the advantage of being based on Django. This meant that it already rendered almost all of our Django templates correctly from the get go and wouldn’t require as much work to migrate everyone over.

Clearly Jinja has a lot to offer, but today we want to focus on the performance advantages, so let’s get benchmarking!


Lean Product Feedback via Email

lean hero image ;)

The Lean Startup movement has undeniably had a massive impact on the startup world as a whole, and it has especially been felt by me and my co-founder, Brad. In the early days of Sendwithus, adopting lean methods for customer development and lean analytics techniques for data decisions was incredibly important to how we validated our ideas. These philosophies are now embedded in our entire team and continue to shape our company.

Today I want to share one aspect of our “lean product” process. We call it lean product feedback, and it’s how we close the loop between customer development and analytics.


How we validated our SaaS product without building it

When we first started sendwithus we had no idea what we were going to build. We knew that transactional email was a problem worth solving and we were determined to build a great solution.

Our first hurdle was figuring out what potential customers wanted. To find an answer, we ran several “lean” product experiments to identify early adopters and measure what features they wanted most in a transactional email service.

This post revisits one of those early experiments! =]


Sendwithus joins AirPair Trusted Partner Experts

Sendwithus is fortunate to have a brilliant technical team committed to building awesome product.  We are proud to announce that we are a Trusted Partner for our friends at AirPair. We are collaborating with over a dozen of the world’s most innovative tech companies to offer trustworthy integration support.


We’ve Made A/B Testing Even Better

Our A/B testing allows you to experiment with different variations of an email to determine which is the most engaging.

Use sendwithus to:

  • easily modify templates to set up your experiment,
  • observe each template’s average success over time, and
  • clearly see which variation is winning.

In this video, learn how to get started with A/B testing.

More Than Text: Sendwithus API Supports Attachments!

The sendwithus dev team launched our most requested feature this week – attachment support on email sends!


Now your transactional emails can include file attachments, such as images and PDFs. This is a major improvement, and a much requested feature for customers who want to A/B test important emails that contain more than just text.

For all the gritty details, check out our API Docs here. We’ll be rolling out new versions of our API Client Libraries with brand new attachment support over the coming days. Watch our github projects for updates!

Snip out Repeated Code with Our New Snippet Support!

We recently introduced a new feature to help improve code reuse in email templates. Our new snippet support lets you define common HTML blocks once, then include them in multiple email templates. Snippets are perfect for components like headers and footers, or smaller components like social buttons and common links.


Head over to our Help Center to learn more about snippets and how to use them.