Red Hat Inc. delivered no big surprises on its quarterly earnings call today, but indicated that growing adoption of its OpenStack and storage offerings could accelerate its growth rate in the future.

The company met analysts’ fiscal fourth-quarter earnings expectations and slightly exceeded revenue forecasts on 18 percent year-over-year growth. Red Hat slightly reduced its earnings outlook for the full year, but said the sole reason was charges related to the acquisition of 3Scale Inc., a maker of software for managing application program interfaces (APIs), which was also announced today. Officials reaffirmed full-year revenue guidance and even nudged expectations slightly higher for the first fiscal quarter.

Investors knocked the stock back anyway, sending it down nearly five percent in initial after-hours trading. But there was nothing in the earnings announcement or subsequent analysts call that would indicate storm clouds on the horizon.

On the contrary, officials said subscription revenues remain strong, with 18 percent growth mirroring total revenue growth. Red Hat enjoyed “the highest Q1 growth rate in US revenue in three years,” said CEO Jim Whitehurst. Application development-related revenues and sales of other emerging technologies reached $98 million in the quarter, up 39 percent over last year.

Analysts at investment firm Barclays PLC liked what they saw. Although “we still think the stock will be under pressure in the short term,” they wrote, “we continue to like the long-term story and maintain our overweight rating.”

Six first-quarter deals came in over $5 million and two of those were over $10 million. “This highlights Red Hat’s growing strategic importance in our customers’ data centers,” said Chief Financial Officer Frank Calderoni.

Officials hinted that things could get better as enterprises grow more comfortable with open-source software in general, and OpenStack clouds in particular. “Red Hat Enterprise Linux (RHEL) is being recognized as the leading deployment platform for enterprise OpenStack across the globe,” Whitehurst said.

Wikibon Analyst Brian Gracely agreed. “The exploration and buying patterns are changing for enterprise and government customers,” he said. “They now expect technology to be open-source or available on the public cloud before sales reps walk in the door. Some are no longer considering software unless it’s open-source.”

Another potential growth area is storage. Only four of the company’s top 30 deals in the quarter had a storage component. Earlier in the day Red Hat announced the latest generation of its software-defined storage platform, Red Hat Ceph Storage 2. Whitehurst also hinted at more stage-related announcements at Red Hat Summit in San Francisco next week.

Taken together, “If RHEL can continue to grow double-digit and OpenStack and storage continue to scale, I feel pretty confident in taking our growth rate up and not down,” Whitehurst said.

“Red Hat is seeing growth in many areas outside of RHEL, such as OpenStack infrastructure-as-a-service, OpenShift platform-as-a-service and Ansible automation,” said Wikibon’s Gracely. “They have been investing in engineering contributions to all of those open communities and projects, and their ability to integrate, package and support that customers is a big advantage compared to smaller startups.”

The 3scale acquisition is a recognition of the centrality of APIs to cloud environments composed of microservices. 3Scale will become part of a growing Red Hat portfolio of middleware products that includes JBoss Middleware, Red Hat OpenShift and the Red Hat Mobile Application Platform. Forrester Research Inc. has estimated that 40 percent of U.S. companies will use API management tools and spend $660 million per year on those technologies by 2020.

The company said 60 percent of its bookings in the quarter just ended came from the Americas, up from 55 percent in the previous quarter. Seventy percent came form channel sales, down slightly from 75 percent. “Overall we are very pleased with our financial performance in the first quarter and we believe we’re off to a good start for FY 17” as IT organizations transition development and production to hybrid cloud, Calderoni said.