AtomicJar Secures $25 Million in Series A Funding and Launches Public Beta of Testcontainers Cloud

As Testcontainers surpasses 100 million downloads, AtomicJar releases Testcontainers Cloud to help developers ship reliable code to production faster with integration tests

NEW YORK--()--AtomicJar, the company behind the popular open source library Testcontainers, today announced that it has secured $25 million in Series A funding and is releasing Testcontainers Cloud as a public beta. Global software investor Insight Partners led the round, with participation from existing investors boldstart ventures, Tribe Capital, Chalfen Ventures and Snyk co-founder Guy Podjarny and CEO Peter McKay. New investors include Irregular Expressions, a VC fund representing 90+ CTOs and heads of engineering of leading tech companies; software industry veteran Walter Scott; and, the co-founders of AtomicJar will use the new funding to scale its development team, to increase the number and types of databases and languages that the Testcontainers open source libraries support, and to improve the shift-left testing developer experience with Testcontainers Cloud.

“We are incredibly grateful to have the support of our investors to help us focus on the testing tools that matter to developers enabling them to ship software with confidence,” said Sergei Egorov, co-founder and CEO, AtomicJar. “Hardly anything can be more expensive than a developer waiting for something, and testing is a common reason for downtime. With Testcontainers, we are shifting testing to the left, from QA teams and staging environments to developers writing and running tests in IDEs. It is like Unit Testing, but with real dependencies thanks to containers!”

“AtomicJar Testcontainers Cloud will maintain the developer-friendly approach that Testcontainers OSS offers, but with all of the features enterprises expect of critical infrastructure,” said Jon Rosenbaum, Managing Director, Insight Partners. “We see the potential for AtomicJar to become a universal developer tool and become synonymous with integration testing.” Rosenbaum will join the AtomicJar Board of Directors.

Microservices Changes How to Test Software

One of the fastest growing segments of the global software testing market is microservices testing. Microservices testing has traditionally been a painful challenge for developers. Testcontainers was founded to solve this problem, and its adoption is now accelerating.

Created in 2015, Testcontainers has transformed test-enabled development at leading engineering organizations like DoorDash, Spotify, Uber, Google, Zalando, and many more, becoming the de facto standard for dev-first testing. In 2022, Testcontainers saw an increase from 50M to 100M in Docker Hub downloads, making it one of the fastest growing open source projects in the testing category. It is currently being downloaded more than 6M times a month.

In response to this huge demand, AtomicJar is releasing Testcontainers Cloud, its first commercial offering, in beta. Testcontainers Cloud is a scalable, on-demand service that unlocks the full Testcontainers experience by supercharging developer laptops and simplifying CI pipelines for developer teams, while eliminating the need to tweak existing tests.

“We’re thrilled to continue backing the AtomicJar team on its mission to shift integration testing left, allowing organizations to ship better code, faster,” said Ed Sim, founder and General Partner, boldstart ventures. “With the beta release of Testcontainers Cloud, AtomicJar is taking what is already loved by the Testcontainers community and making it 10x better, faster, and easier to use. As software applications continue to increase in complexity and dependencies, we’re excited about the massive opportunity ahead for AtomicJar.”

“At AWS, testing was a paramount part of the inner development loop, and getting integration tests to pass was part of the definition of ‘done’ for every check-in,” said Eli Aleyner, part of the founding AWS engineering team and co-founder, AtomicJar. “This culture-shift is similarly happening in other organizations. Developers are looking for self-contained, repeatable, real integration testing solutions that don’t depend on bottlenecks of staging environments - a use-case Testcontainers shines in. I wish Testcontainers had existed when we were building AWS.”

The Benefits of Testcontainers Cloud

Testcontainers Cloud makes adopting Testcontainers simple for any organization. It installs in five minutes, and provides consistency in test results, with faster execution and elastic resources that are always available.

Testcontainers Cloud removes all hardware and software limitations, and is a major productivity booster for engineering teams that want to:

  • Test everything on laptops without worrying about resources (no local Docker daemon needed).
  • Run their ever-growing test suite without scaling their CI workers, and speed it up by running tests in parallel.
  • Enhance team efficiency by getting rid of flaky tests and ensuring consistency from dev to CI.

"We believed in the Testcontainers Cloud vision from day one and we are excited to be working with AtomicJar on adding it to our platform. Our goal is to make the Netflix Testing experience consistent and reduce Docker operational burden. Testcontainers has played a big role at Netflix, and Testcontainers Cloud takes it to the next level," said Roberto Pérez Alcolea, Senior Software Engineer, Productivity Engineering, Netflix. "From our metrics, up to 90 percent of build time is spent in tests, so any kind of consistency or speed improvement can make a massive difference. A few of our engineers already use Testcontainers Cloud on a daily basis and we believe it fits into Netflix's continuous efforts to make developer feedback loop faster by allowing developers to run their tests locally and more frequently regardless of their development environment."

Get Started with Testcontainers Cloud Today

Testcontainers Cloud public beta is available now and free to use. Developers can start testing in minutes. To learn more, please visit:

About AtomicJar

AtomicJar is on a mission to make integration testing easier for developers across the software development lifecycle. Founded by the same team that maintains the most popular integration testing library, Testcontainers, AtomicJar gives developers simpler methods for testing with containers and anything running inside containers, against the many dependencies code integrates with in production. For more information visit or follow

About Insight Partners

Insight Partners is a global software investor partnering with high-growth technology, software, and Internet startup and ScaleUp companies that are driving transformative change in their industries. As of June 30, 2022, the firm has over $80B in regulatory assets under management. Insight Partners has invested in more than 700 companies worldwide and has seen over 55 portfolio companies achieve an IPO. Headquartered in New York City, Insight has offices in London, Tel Aviv, and Palo Alto. Insight's mission is to find, fund, and work successfully with visionary executives, providing them with right-sized, right-time practical, hands-on software expertise along their growth journey, from their first investment to IPO. For more information on Insight and all its investments, visit or follow us on Twitter @insightpartners.


Heather Fitzsimmons
Mindshare PR
+1 650 279 4360


Heather Fitzsimmons
Mindshare PR
+1 650 279 4360