The moment I first learned about Proof of Stake is burned into my memory.

I became fascinated by blockchain technology in early 2016, with its promise of delivering a permissionless, censorship resistant, global platform. I’d come across a draft of the book Bitcoin and Cryptocurrency Technologies, and I loved what I was learning. But the whole Proof of Work thing made me quite uneasy. I’ve always had keen environmental antennae; my graduate research twenty years earlier had been in climate dynamics. I knew that Proof of Work – or Proof of Waste as I have come to think of it – could never be sustainable as the settlement layer for the planet.

The moment of enlightenment came when I reached section 8.5, over 200 pages into the book: “Proof‐of‐Stake and Virtual Mining.” The idea was simple but brilliant. Instead of securing the chain by spending money on mining equipment and power, we just skip all that and secure the protocol directly with money staked by “virtual miners”. This ingenious approach completely resolved my concerns, and when I learned of Ethereum’s plans to transition to Proof of Stake I was well and truly hooked. It wasn’t much longer before I jumped in full time by joining PegaSys, the Protocol Engineering group at Consensys.

At the start of 2018 I decided that I wanted to work exclusively on the future of Ethereum’s mainnet, on Proof of Stake and scalability. To be honest, I had feared some push-back when I put this to my colleagues since PegaSys was mostly concerned with private, permissioned networks at the time. In the event, I was delighted with the unreserved support I received, and I am thrilled today that the majority of the work we do now in Consensys Protocols is mainnet-focused.

I kicked off the project that became Teku (originally called Artemis) in September 2018. I was leading the Protocols R&D group, and building an Ethereum 2 client seemed like a natural extension of the research we were doing. So we gathered a team and started coding.

There were six or seven other client teams around at the time, and the Eth2 specification was very much still under development. The work was an exciting mix of research, engineering, coding, and collaboration. A year later, Consensys funded the first ever Eth2 devs’ offsite. Around thirty devs from all the teams spent a week in a cabin in Ontario (Canada) plugging all the clients together for the first time. It was a huge success.

Around the time of that event, we decided to transition Teku from R&D over to our product development group. We’d built a great prototype, but there was to be a long journey from there to a robust, secure, product-quality client implementation. I also moved over to do the product management and we built another team, with some experienced hands joining from Besu, our Eth1 client team. On December 1st, 2020, I was immensely proud (and not a little nervous) as Teku took part in the genesis of the Ethereum 2 beacon chain as one of only four production-ready clients.

While Teku is certainly a very capable client – it powers Infura’s Eth2 service as well as Consensys Codefi’s staking service and several other large staking operations –  for me as Teku’s product lead, the client itself remains only part of the story. For me, the process is as important as the product. I believe that the true value in building Teku comes from the opportunity it gives us to participate in protocol development, from helping to bridge the engineering gap between theory and implementation. The real gold for me is in working as part of an entire community to make Ethereum better.

I had no idea on that day six years ago that it would take us so long to deliver Proof of Stake. The journey has been longer and tougher than anyone thought. But The Merge is finally upon us. Equally, I could barely have imagined that I might play some kind of small role in making it happen; that I might even end up writing the book on how we did it. The openness of the Ethereum community has always encouraged engaged and motivated individuals to have an impact, and that remains true today. I would urge anyone to get stuck in.

I am deeply grateful for Consensys’ ever consistent support and encouragement in all of this - the company has empowered me to work on what I think is important. This ought to be commonplace, but in my experience is in fact rare. The days when I felt like an outlier for wanting to devote my time to the open public mainnet protocol are long behind. Supporting mainnet development is a huge part of what we do now as an organisation. I love the fact that we have been able to do so much to progress The Merge, whether through open source software development like Teku and Besu, or through our broad and open R&D contributions. It continues to be a wonderful journey.

For regular updates and news on the Merge, visit the Consensys Merge Knowledge Base, where you’ll also find Merge archives with key milestones achieved and other essential resources for developers.