PubNub Leadership Team

Leadership Team

  • Todd Greene
    Founder & CEO

    As an entrepreneur who has founded and successfully sold companies across the software spectrum, Todd helps shape the PubNub vision of revolutionizing the way people interact online. Todd most recently was CEO of Loyalize, an Audience Participation company successfully sold to Function(x) (FNCX), a Robert F.X. Sillerman company, where he designed the first-ever massively multi-user Social TV mobile and web applications licensed to companies like Viacom and Yahoo. Todd previously was founder and CTO/VP Products of CascadeWorks, a company providing Services Procurement solutions to Texas Instruments, Charles Schwab, and ABN Amro, and acquired by Elance. After working with companies like GE, SGI, and Quantum while a consultant at Price Waterhouse, Todd joined NetDynamics (sold to Sun Microsystems in 1998) to help create a truly game-changing product: the first application server built for the Internet.

  • Stephen Blum
    Founder & CTO

    Stephen's vision and strong technical chops drove the initial architecture of PubNub, building a core engine that has successfully scaled to the some of the largest realtime deployments in the world. Stephen has been a successful software entrepreneur his whole life, starting his first company, LTSun, at age 17, and joining Microsoft after its acquisition. 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 is a seasoned CFO with over 10 years of experience working with venture backed consumer Internet, online advertising and SaaS companies. He has successfully managed and advised companies through all stages of the start-up life cycle, from pre-revenue through rapid growth and ultimately, to successful acquisition. Prior to PubNub, Russ was at Kranz & Associates, and before that was CFO of Extole, Inc., the leading SaaS provider of social marketing solutions for brands. Prior to joining Extole, Russ was CEO and CFO at TravelMuse. He is also the former interim CEO and CFO of SideStep. He joined SideStep at the “idea” stage and successfully built it into one of the Internet’s leading travel sites. Prior to SideStep, Russ oversaw corporate development at Komag, Inc. Russ began his career as a management consultant with Ernst & Young’s Financial Advisory Services group. Russ holds a B.A. degree from CalPoly SLO and received an MBA and JD from University of San Diego.

  • Casey Clegg
    Chief Revenue 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 that drove 15x growth in revenue over five years culminating in the 2016 IPO. Before that, Casey started and built the API business unit at Yodlee, growing the division to half of all revenues 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.

    VP Business Development

    Jonas brings over 20 years of experience in business development, marketing, and new technology to PubNub. Prior to joining the team, Jonas served as SVP, Global Business Development & Brand Partnerships at UberMedia (part of Idealab) where he created partnerships with numerous Fortune 500 clients and helped pivot the company from social media app development to one of the leading providers of mobile ad tech. He also served as SVP of Marketing at Big Stage Entertainment, a 3D entertainment company that was acquired by Image Metrics in 2011. 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 in 1997 before being merged into CDnow and acquired by Bertelsmann in 2000.

  • James Hamilton
    VP Operations & Controller

    Hailing from the midwest James thrives in helping structure companies for growth, bringing over 20 years of diverse financial and operations leadership experience. James began his career early while at UW Madison leading a finance team at Genetics Computer Group (now part of BIOVIA) then working in management consulting at PricewaterhouseCoopers. At 1WorldSync he helped scale operations across Europe and South America and at Pacific Maritime Association he improved financial operations across over 40 entities in 32 locations. Outside of work James enjoys working with teenagers, helping them navigate life’s challenges. He spends his weekends hiking the Marin headlands with his wife, dog and 2 kids as well as honoring his Wisconsin roots hanging around the hockey rink.

  • Helena Teav
    Associate 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 thinks creatively about how to resolve issues, and directs legal strategy to avoid disputes down the road. 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 BA and BS from Santa Clara University and a JD from UC-Hastings College of the Law.


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

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

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.

Stephen Zocchi

Stephen is the Founder and CEO at Allayo, a mobile health assistant platform for adherence and wellness that connects health care and consumers. A start-up veteran with a proven record of building successful companies, his experience includes two company IPOs and 2 acquisitions. Prior to Allayo, lead the growth of Model N from $13M to $65M as SVP of Sales and VP of Marketing. Previous experience also included VP Marketing at CascadeWorks, VP of Marketing and Business Development at NetDynamics.

Anshu Sharma

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.

Greg Simon

Greg likes to work on disruptive technologies and products. Previously he created webOS at Palm -- blurring the lines between native and web. Prior to that he kicked-off the iPod/automobile integration fad by creating the BMW iPod adapter. While still in grad school he wrote the web browser engine for the Apple Newton. Currently Greg leads the team working on the Blink web rendering engine at Google that powers Chrome, Chrome OS, and many other browsers.

Doron Sherman

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

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.