“It absolutely makes it easier to write applications,” said Eric Brewer, Google’s vice president for computer infrastructure. Google developed the first type of container, for internal use, about eight years ago, which helped it build its Internet services quickly.

Docker took the Google innovation and made it easy for people to use across computers.

“It’s a huge efficiency gain in how you write code,” said Mr. Golub, who started his career teaching business courses in Uzbekistan. “You don’t have to rewrite everything, then fix all the breaks when it goes into production. You just work on what you change.”

Mr. Golub’s office has a turtle, he jokes, “so that I’m not the worst coder.”

Some big companies have noticed what the 70-employee start-up is doing. The European bank ING uses Docker to update 1,400 different applications a day. Gilt Group, an online store, turned seven big applications in its website into 400 smaller pieces, making it easier to update. And Goldman Sachs uses Docker to build and deploy the software it runs internally.

“Our underlying software was getting so spread out” that it was difficult to manage, said Don Duet, a global co-head of technology at Goldman. “Docker is a central place where you can put everything.” A 26-year technology veteran, he compares software containers in importance to Java, a programming language created in the 1990s that led to rapid growth of the commercial Internet.

At least for now, Docker’s small size and independence may be assets, since it is able to play with the giants without seeming like a threat. Microsoft in October announced it would work with Docker to put its Windows operating system in containers (Docker already works with several types of Linux, the operating system commonly used in the servers of many big clouds). IBM is working with Docker to increase the international deployment of containers. And Google and Amazon have both endorsed Docker at their events for software developers.