PubNub 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 constant 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.

    VP of Customer Success

    Assaf brings over 20 years of experience in pre and post sales leadership and management. Prior to PubNub, Assaf led Customer Success, Professional Services and Solution Consultants functions at companies such as Zendesk (IPO in May 2015), eMeter (acquired by Siemens), IBM and Amdocs. Assaf began his high-tech career as an engineer, system-admin, DBA and was responsible for managing high growth teams. Assaf is happiest when customers achieve their goals, and believes that a great customer experience is paramount. When not managing PubNub's Center of Excellence, Assaf can be found playing the piano, training new generations of soccer referees and spending time with family. He holds a Bachelor degree in Business and Finance from Bar-Ilan University, Israel.

  • Casey Clegg
    VP Sales

    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.

  • Simon Jones
    VP Marketing

    Simon is a Silicon Valley veteran, with two decades' experience in building, marketing, and selling innovative B2B products. Most recently, Simon was Evangelist and Head of Marketing for Cedexis, an intelligent Interenet traffic management company, which was acquired by Citrix in early 2018. Prior to Cedexis, he successfully built and unleashed the value of companies like Ooyala (acquired by Telstra), Plimus (acquired by Great Hill Partners), and Hyperion (acquired by Oracle). A graduate of Oxford University he lives and coaches baseball in Burlingame with his wife and three kids.

  • Steve Garritano
    VP Engineering

    Steve brings over 2 decades of engineering leadership and IT operations to PubNub. Most recently, Steve was VP Engineering at Aviatrix, a pioneer in hybrid cloud networking. Prior to that, Steve served as the senior engineering executive for multiple cybersecurity technology firms, including PhishLabs and RedSeal Networks where he was responsible for the research and development of their network security monitoring and risk assessment products.

  • Marc Friend
    Senior Advisor

    Marc has played key roles in both software startups and as an investor and entrepreneur. Marc served as Chief Operating Officer and CFO at Intalio, a enterprise software company, where he led finance, marketing, sales operations and administration for a growing team. A 15-year veteran of the venture industry, Marc has served in General Partner roles at USVP and Summit Partners and as a Venture Partner at Partech International. He made investments in ground-breaking companies in internet infrastructure including NetDynamics, Check Point Software, Blue Martini Software and Marc earned an MBA from Harvard Business School and his bachelor's and master's degrees in Electrical Engineering from Massachusetts Institute of Technology


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.

Zack Urlocker
Board Member

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
Board Observer, 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.

Jai Das
Board Observer, 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
Board Observer, Robert Bosch Venture Capital GmbH

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.

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.