The PubNub Leadership Team

Leadership Team

  • Todd Greene
    Founder and CEO

    As an entrepreneur who has founded and successfully sold companies across the software spectrum, Todd shapes PubNub’s vision of powering apps that bring people together, virtually. Prior to PubNub, Todd was CEO of Loyalize, where he helped build the first-ever social TV app and successfully led their acquisition by Function(x) (FNCX). Todd also founded CascadeWorks and spearheaded their sale to Elance. He has also held prominent roles at GE, SGI, Quantum, Price Waterhouse, and NetDynamics—where he assisted in creating a truly game-changing product: the first application server built for the internet.

  • Stephen Blum
    Founder and CTO

    Stephen's vision and strong technical chops drove the initial architecture of PubNub. He built the core engine of PubNub, which has allowed the company to successfully scale to power some of the largest real-time deployments in the world. Stephen has been a successful software entrepreneur his whole life. He founded his first company, LTSun, at age 17, and joined Microsoft after its acquisition. Additionally, Stephen was the chief architect for, a 50-language social recommendations site that grew to over 1 million users across over 100 countries.

  • Russ Lemelin
    Chief Financial Officer

    Russ has over 10 years of experience working with venture-backed SaaS companies. He has successfully managed and advised companies through all stages of the start-up life cycle, including acquisitions. Prior to PubNub, Russ was the CFO of Extole, the CEO and CFO at TravelMuse, and the interim CEO and CFO of SideStep. He joined SideStep at the idea stage and successfully built them into one of the internet’s leading travel sites. Russ began his seasoned financial career as a consultant with Ernst & Young’s and with an MBA and JD from the University of San Diego.

  • Casey Clegg
    Chief Operations Officer

    Casey has over a decade of experience building developer-focused sales teams. Prior to joining PubNub, Casey was part of the sales leadership team at Twilio. In that role, he drove 15x growth in revenue over five years, which culminated in Twilio’s 2016 IPO. Before that, Casey started and built the API business unit at Yodlee. He grew his division to account for half of all revenue in the years leading up to the company's IPO. Originally hailing from the Bronx, by way of the Chicago suburbs, Casey lives in the Bay Area with his wife and two sons. Casey is a graduate of New York University and has an MBA from UCLA Anderson.

  • Jonas Gray
    VP, Business Development

    Jonas brings over 20 years of experience in business development, marketing, and technology to PubNub. Prior to joining the team, Jonas served as SVP, Global Business Development and Brand Partnerships at UberMedia (part of Idealab). In that role, he created partnerships with numerous Fortune 500 clients. He also served as SVP of Marketing at Big Stage Entertainment. Earlier in his career, he helped build the first online DVD retailer (DVD Express) and the first online music company (N2K), which completed a successful IPO.

  • JP Shipherd
    VP, Product

    JP has a strong background in creating developer ecosystems around human/machine interface products and solutions. He has over 25 years of experience working in solution spaces including handwriting and speech recognition, contact centers, and collaboration. The developer interfaces he has helped create have enabled his companies’ products to be embedded in a wide variety of solutions that span use cases and vertical markets. JP is a New York state resident and graduate of New York University, but with strong Bay Area ties.

  • Scott Hill
    VP, Engineering

    Scott is a seasoned engineering leader, with over twenty years of experience leading engineering teams in a variety of environments. He has a wealth of experience creating strong Agile/Scrum development teams and empowering them to create large-scale, web and cloud-based platforms. Scott honed his technical skills as an architect at companies such as Signio (acquired by VeriSign) and PayPal. Prior to joining PubNub, he was the Head of Engineering for Data Security at Micro Focus. A native of the San Francisco Bay Area, Scott lives in Belmont, California with his wife and daughter.

  • James Hamilton
    VP, Operations and Controller

    With over 20 years of diverse financial and operations leadership experience, James thrives in helping structure companies for growth. He began his career at University of Wisconsin–Madison, leading a finance team at Genetics Computer Group (now part of BIOVIA) and as a management consultant at PricewaterhouseCoopers. At 1WorldSync, he helped scale operations across Europe and South America, and at Pacific Maritime Association he improved financial operations across more than 40 entities. Outside of work, James spends his weekends hiking the Marin headlands with his wife, dog, and two kids and honors his Wisconsin roots by hanging around the hockey rink.

  • Helena Teav
    General Counsel

    Helena has represented established technology companies for many years, resolving international and domestic issues relating to commercial agreements and technology transactions. She is an experienced negotiator who is passionate about drafting technology contracts and enjoys working on corporate matters, licensing, privacy and data security, employment law, and compliance. She began her career over two decades ago at Adobe Systems. Prior to PubNub, she worked at Citrix Systems, was general counsel at a financial services company, and worked in private practice. Helena holds a JD from UC-Hastings College of the Law.

Our Board and Advisors

Kevin Talbot
Board Member, Relay Ventures

Kevin is a Co-founder and Managing Partner at Relay Ventures. Kevin has been an entrepreneur, operator and investor in both Canada and US for over 20 years. Prior to co-founding Relay Ventures, Kevin was with the venture capital arm of Royal Bank of Canada where he was Vice President of Venture Capital and Managing Director of RBC Venture Partners.
Kevin holds an MBA with distinction from York University, Schulich School of Business, a BA degree in Strategic Studies from York University, and the ICD.D designation from the Institute of Corporate Directors’ Corporate Governance College at the Rotman School of Management. Kevin is the author of ‘Strictly Mobile – How The Largest Man-Made Platform in History is Changing Our World’ and the curator of the Strictly Mobile and Flying Upside Down conferences. He is a frequent public speaker and delivered the TEDx talk Hope is Not a Strategy in Brussels in 2014. Kevin is based in our Menlo Park office.

Andy Vitus
Board Member, Scale Venture Partners

Andy is a Partner at Scale Venture Partners (ScaleVP). Andy focuses on ScaleVP’s investments in next-generation enterprise software and new point of presence technologies – including virtualization and cloud computing. Prior to joining ScaleVP, Andy worked as a hardware engineer for Electronics for Imaging, designing embedded print server platforms and video compression circuits. Andy sits on the boards of Arena, Boundary, DataStax, Entone, PubNub, and INNOViON.

Jai Das
Board Member, Sapphire Ventures

Jai is a Managing Director at Sapphire Ventures. His primary focus is in the areas of software-defined infrastructure, cloud and mobile computing, smart machines, IoT and pervasive analytics. Jai has more than 15 years of experience helping companies innovate their product and marketing strategies in order to scale and become market leaders. He has led and manages the firm’s investments in Alteryx, Box (BOX), Cyphort, Five9 (FIVN), Justdial (JUSTDIAL), Mirantis, Mulesoft, Narrative Science, Nutanix, PayTM, PubNub, Socrata and Square.

Luis Llovera

Luis is an employee of Robert Bosch LLC. He is a non-executive board director of RBVC’s portfolio companies Nextreme and Ogmento. Prior to joining Bosch in 2008, Luis was an Investment Partner for over 6 years with Siemens Venture Capital. Some of his investments included Agility Communications (acquired by JDSU), PubNub, GENBAND, Covega (acquired by Gemfire) and Polychromix. Luis has over 17 years of operating experience in the hi-tech industry.

Amit Chaturvedy
Board Observer, Cisco Investments

Amit leads global venture investing and M&A efforts in Internet of Things. Prior to Cisco, Amit was at Summit Partners where he led investments in Fleetcor (NYSE: FLT), MA-Com (NASDAQ:MTSI) and Rocket Internet (ETR: RKET). Previously, he was at Cummins Inc. where he led software development and product marketing activities. Amit also worked in investment banking at Citigroup, NY. He has led and managed Cisco’s investments in Ayla, Bitstew,, McRock Capital, PubNub, relayr and Veniam.

Albert Kim
Board Observer, Ericsson Ventures

Albert is the head of Ericsson's corporate venture capital group, based in Silicon valley. He represents Ericsson as a non-executive director on the boards of Pluribus Networks and Pubnub, and also manages Ericsson's investment in Drawbridge. Prior to joining Ericsson in 2014, Albert was a Managing Director at Investor Growth Capital, where he spent over 13 years in growth stage venture capital. Albert has a PhD in Applied Physics and also dabbled in banking (Goldman Sachs) and consulting (McKinsey) before joining IGC.

Abhishek Shukla
Board Observer, HPE Pathfinder

Abhishek leads the venture investments for HPE Pathfinder across the HPE Portfolio ( including Aruba). Abhishek joined Pathfinder from GE Ventures where he was a Managing Director of software investing. His areas of focus at GE Ventures included IoT, cybersecurity, cloud+ edge computing and data analytics. He has served on numerous boards while at GE Ventures and Cisco including IoTium, Portworx, ThetaRay, Alchemist, The Hive, Equalum, Morphisec, Xage, Verodin, Flashpoint and eSentire. Abhishek received his MBA from the Haas School of Business at the University of California, Berkeley, and a Bachelor of Engineering in Electronics from the Delhi College of Engineering, India.

Anshu Sharma
Advisor, Skyflow

Anshu is a software industry executive with over 15 years of experience at leading enterprise software companies like Oracle and Most recently, he served at Salesforce for over 5 years as the vice president of products for Salesforce Platform where he led Salesforce's entry into Java platform as a service, Identity Management, Database as a service and next generation marketing platform. As an angel investor in early stage ventures and advisor to leading venture firms, Anshu works with strong engineering and product teams to define their go to market and long term product strategy.

Doron Sherman
Advisor, Cloudinary

In a career spanning 25 years, Doron co-founded and served in technical executive roles in software companies that made critical contributions to the enterprise software and internet infrastructure industries. He co-founded and was Chief Scientist of NetDynamics, a leading application server pioneer (acquired by Sun in 1998), CTO of Collaxa, inventor of the BPEL web services orchestration server (acquired by Oracle in 2004) and Director of Kindling, a high-participation venture management fund specializing in Internet/B2B startups.

Zack Urlocker
Advisor, Gatsby

Zack is an executive, investor, advisor and board member with over twenty years of experience in the software industry. He has helped scale revenues in startups from under $6 million to over $100 million and has had multiple billion dollar exits. He has held executive positions at Borland, Active Software, MySQL and most recently as Chief Operating Officer at Zendesk. He is a frequent speaker on disruptive technology and occasional marathon runner.

Prashant Shah
Advisor, TiE Angels

Prashant is Managing Director of TiE LaunchPad, an accelerator for enterprise startups. He is an active Charter Member of TiE Silicon Valley (, a member of its Board of Directors, and Head of TiE Angels. Prashant Shah has been an early stage venture investor since 2001. Previously, he spent nearly 10 years at Hummer Winblad Venture Partners, an early stage VC focused on enterprise and infrastructure software.