Complexible Inc is a privately-held software company based in Washington, DC, and Boston. We make Stardog, the leading semantic graph database, and other fine software products. Founded in 2005, we have been active in all phases of semantic technology, including research, commercialization, and standards-making. We launched Stardog in 2012 and rebranded as Complexible Inc in 2015.


Kendall Clark is co-founder and CEO. Kendall has been a computer science researcher, software developer, writer, editor, philosopher of religion, yard boy, and construction worker. He lives in Washington, DC, with his beautiful wife, two indomitable daughters, and two big dogs.

Michael Grove is co-founder and VP of Engineering. He is a graduate of the University of Maryland in Computer Science, and alumnus of its MINDLAB, a seminal research group in the semantic web. Prior to Complexible, he co-owned Lightning Round Entertainment which specialized in creating novel online games and did research on Task Computing using semantic web technologies while at Fujitsu Labs of America. He lives near Baltimore, Maryland with his wife and daughter and can often be found at an Orioles game at Camden Yards.

Evren Sirin is co-founder and CTO. Evren has been working on Semantic Technologies since 2001, and he is one of the lead developers of Stardog and Pellet. He holds a PhD in Computer Science from University of Maryland, College Park. He lives outside Boston, with his wife, daughter, and twin sons, where they survive cold winters and enjoy mild summers.

Al Baker is VP of Enterprise Solutions. Before Complexible, Al led development teams creating next generation software solutions at Booz Allen Hamilton, Avaya, and Lucent. With a passion for open source, he's developed many Stardog client integrations including Clojure, Groovy, and Spring.

Steve Bastasini is VP of Business Development, Strategic Alliances, & Sales. Steve co-founded several Internet and Semantic Web Startups and has worked in various leadership positions for over twenty years. When he's not working, you can find him on the beach in San Diego with his two children and their dog LeeLee.

Michael Soren is a Distinguished Software Engineer at Complexible. Prior to Complexible he worked as a technical lead and developer in the telecommunications, pharmaceutical and financial industries as well as the U.S. Department of Defense. He lives in upstate New York and enjoys solving problems in mathematical physics.

Stephen Nowell is a Senior Software Engineer. He studied Software Engineering at Shippensburg University of PA. Before Complexible, Stephen worked for the Army and the financial industry. He currently lives in York, PA with his wife, Amanda.

Fernando Hernández joined Complexible as a Software Engineer in January 2013. Before Complexible he was a master's student at TU München in Munich, Germany. He lives in northwest Washington, DC and enjoys running, reading, geeky t-shirts, and casual gaming.

Pavel Klinov is a Senior Research Engineer. He first joined the company in 2007 as a research intern and then continued in 2011 as a Senior Developer responsible for a number of core Stardog's components, including the query planner. Before Complexible he worked at CERN and graduated with a PhD in Computer Science from the University of Manchester. Pavel is also the company's first employee in the EU (Germany).

Kate Krizan is a Visual Designer. She brings a load of media experience and right-brained thinking to Complexible. When she's not busy kerning, Kate likes to shop for new fonts. And feed stray cats.


We're always looking for great people to join us. Our culture is based on engineering excellence, mutual respect, collegiality in all things, rigor in design, research, implementation, and testing...and a deep suspicion of corporate bullshit. We care deeply about work-life balance and productivity in the short and long run. In sum, if you remove the unnecessary, the distracting, and the tedious, what you're left with is a healthy 40 hour week full of wins.

We offer remote work in the right circumstances, as well as offices in Washington, DC and Boston.

If you're interested in joining us to work on Stardog, drop us a line.

Sales Representative

Demand for enterprise data unification via Stardog is growing every day. Come help us sell Stardog into the best companies on the planet. We're looking for experienced, early to mid-career sales reps who are ready to help us push Stardog to the top. We have openings on the East Coast, West Coast, and the Central TZ, too.

Distributed Systems Engineer

The future has always been distributed and the future is arriving now. We're building cutting-edge distributed graph systems, with particular focus on Spark, Flink, and DCOSes.

Database Engineer

Stardog is the leading semantic graph database; if you know Datalog from LP from distributed joins—or if you dream about costing and query planners—you really should be working here.