Introducing SendGrid Labs and its free application load testing service, Loader.io


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Loader-beta-logoSendGrid Labs is a new and growing internal effort at SendGrid. Born in late 2012, SendGrid Labs builds tools and services to help developers focus on their core business. It aims to provide creative and innovative solutions to common developer pain points to make their lives easier, and to help them scale. SendGrid is the ideal platform for an initiative like Labs, because it already solves a major developer pain point—email deliverability, infrastructure, and scalability. Like every other tech company, SendGrid has experienced growing pains, and has had to utilize tools like those being generated at SendGrid Labs to help us scale. We want to give back to our fellow developers who have made SendGrid what it is, by spinning out the tools we’ve developed for others to use.

SendGrid Labs’ first project is application load testing service, Loader.io, which was released in private Beta in December 2012. Loader.io was born out of a performance need that we experienced here at SendGrid—as tends to happen when developers build apps that need to scale. As SendGrid grew, we needed to ensure that our infrastructure could withstand big growth and we needed to test it daily. While most developers continually test for functionality, not all developers regularly test for load performance and scalability. We needed to be able to simulate large numbers of connections hitting our services, in order to ensure our performance integrity.

Loader.io does just that. It allows developers to stress test their web apps and APIs with up to 50,000 concurrent connections. It’s a quick and easy cloud-based service that shows you stats in real time…and is free. Other services can be complicated and expensive (they substantially increase their prices as a user’s connection numbers rise). These high rates can prohibit developers from load testing on a regular basis. We want developers to build load testing into their daily coding and deployment routine, allowing them to focus on scalability and performance—that’s why whether you use 500 connections or 50,000, Loader.io is always free. Users also benefit from unlimited tests with duration times of up to 20 minutes as well as the ability to schedule tests and repeat them daily.

In just a short time, Loader.io has made over 1 billion connections, has run over 5,000 tests, and has over 1,500 registered apps. Thus far, our user base has been organically grown from both word of mouth and developer press and spans a variety of industries.

Moving forward, integrations will continue to be a main focus for Loader.io. So far, we have add-ons with Heroku, cloudControl, and AppHarbor, with more in the works. We are also continuing to integrate with monitoring and testing suites that developers are already using, including NewRelic, Scout, and CopperEgg. With these integrations, users are able to see side-by-side comparisons of their monitoring statistics and our load tests.

We’re excited about Loader.io’s growing developments and for all that’s in store for SendGrid Labs. Our core team will continue to work on anywhere from 2-3 projects at a time—some of them are brand new technologies inspired by interacting with fellow developers, others are tools that we’ve utilized internally—all of them aim to let developers be more successful. We have lots of ideas in the pipeline and we’re continuing to build our team as our needs grow. We’ll be rolling out a lot more tools in the near future, so be sure to check back with us soon for more announcements.

We’re eager to hear about your experiences with your current load testing service and what tools you’d like to see SendGrid Labs develop in the future. Leave a comment below or email me at mike.rowan@sendgrid.com.


Mike is the VP of Research and Development at SendGrid. He has one goal—to make developers' lives more awesome. He has a long history of leading R&D efforts—he developed a worldwide data analytics platform in the early 90’s and founded one of Rhode Island's earliest ISPs in 1995. Before spearheading SendGrid Labs, Mike co-founded several companies, serving as both CTO and head of R&D.

2 thoughts on “Introducing SendGrid Labs and its free application load testing service, Loader.io

  1. Is there any documentation (other than API related) on how to get tests set up and run? Anytime I try to add a payload file to my test I get a 500 error. My payload file is basically a text file containing JSON which I would like posted to the URL endpoint identified in my test.

    • Hi Chris. Thanks so much for your comment. We have received your support request in the loader.io support queue and are investigating the issue. We’ll be in contact via your support ticket with more details.

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