Nexa: The Art of Building a Blockchain

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Nexa: The Art of Building a Blockchain
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This time, we want to revisit the ideology, goals, and legacy of the Nexa blockchain and the Bitcoin Unlimited team behind it. The journey began more than a decade ago, when a small group of passionate and enthusiastic people met on the BitcoinTalk forum. Since then, a lot has happened, a long road has been traveled, and much experience has been gathered.

This article won’t be technical, and for some industry veterans, the story is well known, but for everyone else, grab a cup of tea and let’s review where Nexa is coming from and who is building it.

The Backstory

In the early days of Bitcoin, there was one place where almost everything happened: the BitcoinTalk forum. There were no Twitter threads and no Discord servers, no polished conference stages, and just a message board where the curious, the technical, and the stubborn argued. This is where our story begins, and where the people who build Nexa today first met each other.

Back then, nobody used their real names; everyone was anonymous, and your insights were what really mattered. If you scrolled through the big-block and scaling discussions between 2012 and 2016, you kept bumping into the same nicknames again and again:

  • solex — Andrew Clifford, today the President of Bitcoin Unlimited.

  • thezerg — Andrew Stone, the lead developer who would go on to write the Bitcoin Unlimited client and, later, Nexa itself.

  • sickpig — Andrea Suisani, a core developer who had been around Bitcoin since 2011.

  • ptschip — Peter Tschipper, the engineer behind one of Bitcoin Unlimited’s most important pieces of technology.

  • Peter R — Peter Rizun, a physicist by training who became one of the most published researchers of the scaling era.

They met in the trenches of a now-legendary forum thread called “Gold collapsing. Bitcoin UP”. A marathon discussion that started back in 2012 and, remarkably, is still alive today, well over a thousand pages later. It began as a conversation about gold versus Bitcoin and slowly became the watering hole for a whole generation of people who believed Bitcoin would change the world if only it were allowed to grow.

The Scaling Debate

The team behind Nexa formed more than a decade ago on the famous BitcoinTalk forum, where they discussed and improved Bitcoin itself. The best-known topic from those discussions was the Bitcoin scaling debates. It might sound technical at first glance, but we will simplify the terms.

The thing is, Satoshi set a 1MB block-size limit when Bitcoin was small and vulnerable, and it was meant to be just a temporary limit. The block size limit describes how many transactions can fit into a block. Simply put, back in the days when demand wasn’t huge, the limit made sense as an anti-spam feature. However, it was never meant to stay there, and with increasing demand, the block size limit was supposed to be increased; the initial limit was as high as 32 MB before a temporary limit was imposed. It simply means that the larger the block, the more transactions and activity it can accommodate.

After Satoshi vanished, the community couldn’t agree on how to move forward with scaling Bitcoin. The camp separated into two: “small blockers” who wanted to keep blocks small and scale Bitcoin with Lightning or second-layer solutions. The other camp was “big blockers” who envisioned massive on-chain scalability and saw it as possible to maintain the original use case of digital peer-to-peer electronic cash.

The same group of big blockers later on in 2015 formed the team called Bitcoin Unlimited, led by today’s Nexa lead developer, Andrew Stone. The main goal was to scale Bitcoin on-chain, starting with the block-size limit, and in the years that followed, through innovations such as native tokens and smart contracts, features envisioned by Bitcoiners during those debates.

The signature idea of BU was simple: Emergent Consensus. Instead of a single number hard-coded by a few developers, Bitcoin Unlimited lets the network decide how big the blocks should be, and node operators and miners can signal what they are willing to accept and what kind of block limit constitutes network consensus. The idea was the opposite of how the Bitcoin network functions today: rather than forcing users to operate within limits, users themselves can form consensus and set those limits. This was bottom-up development, one of the fundamental principles of a decentralized network.

From 2016 through early 2017, Bitcoin Unlimited became the most serious big-block challenger Bitcoin has ever seen. At the height of the debate in early 2017, support among miners for bigger blocks briefly climbed above 50%, with Bitcoin Unlimited leading the charge, the closest the big-block movement ever came to changing Bitcoin itself. Ultimately, Bitcoin chose the small-block path, shifting its narrative from digital electronic cash to digital gold.

Ideas Ahead Of The Time

Over the years, the team behind Nexa has proposed real, concrete ideas to Bitcoin itself. For the most part, Bitcoin filed them away. But those ideas never went away, and today you can find them living within Nexa.

On the 2 May 2014, solex (Andrew Clifford) opened a thread on BitcoinTalk that, in hindsight, reads like a blueprint for Nexa. His fix was to stop making people wrestle with decimals and count in whole units he called “bits”, because, as he put it, “Many people are not comfortable with scientific notation or with small decimals such as 0.001234… Most people are happier dealing with 100,000 than 0.00001.” The forum agreed: in the thread’s own poll, 570 of 768 voters, nearly three quarters, backed the idea, but Bitcoin adopted “bits” only as an optional label. Nexa built its money around it, which is why its supply is counted in whole numbers instead of long decimals.

A few years later, Andrew Stone set out to let anyone issue their own assets directly on a Bitcoin-style chain. He described his mechanism plainly in his own specification: “OP_GROUP tokens are a method for implementing representative tokens, also named ‘colored coins’ within the bitcoin community”. In his 2017 proposal to bring it to Bitcoin Cash, he spelled out what made it different: the network itself would police the tokens, with “miners validate the colored coins, as part of normal transaction validation”. Nexa’s own documentation opens its token section with “Groups are a method for implementing representative tokens, also named ‘colored coins’ within the cryptocurrency community.”

And then there is Peter Rizun, who brought peer-reviewed rigor to arguments that usually generated more heat than light. In his 2015 paper he set out to show, in his words, “how a rational Bitcoin miner should select transactions from his node’s mempool, when creating a new block, to maximize his profit in the absence of a block size limit”, and concluded that a runaway “unhealthy fee market, where miners are incentivized to produce arbitrarily large blocks, cannot exist since it requires communicating information at an arbitrarily fast rate.” The next year he published again, in Ledger, the first peer-reviewed cryptocurrency journal, which he helped create as “co-founder and co-managing editor”, on the problem that “orphan risk for large blocks limits Bitcoin’s transactional capacity while the lack of secure instant transactions restricts its usability”.

Then, in October 2017, the team stopped theorizing and proved it. Alongside Andrew Stone and partners including nChain and the University of British Columbia, they announced that “the world’s first 1.0001 GB block was mined and propagated on the Gigablock testnet”. A block over a thousand times larger than Bitcoin allowed, and their honest finding was that the limit was code: “the bottlenecks we found were not related to the protocol or the infrastructure, but they were bottlenecks in the implementation, namely inefficiencies in the Satoshi codebase.”

Building “A Home”

After years of arguments, fights, and scaling debates, and later work on the Bitcoin Cash blockchain, the Bitcoin Unlimited team decided to do it right and build the next blockchain that would inherit Satoshi’s vision, support massive on-chain scalability, be programmable, and handle smart contracts.

Nexa launched on 21 June 2022, in a fair launch just like Bitcoin, and is the chain the team had been describing, sketching, and arguing for since they first met on the BitcoinTalk forum. Nexa’s documentation puts its heritage as “a modification of Bitcoin Cash, which is a modification of Bitcoin.” A direct line, all the way back to Satoshi, carried forward by the people who never stopped believing Bitcoin was meant to scale.

And you can see every lesson from that long road baked into the design. Nexa is a proof-of-work chain, keeping the security model that made Bitcoin trustworthy. It uses the same proven UTXO accounting Bitcoin pioneered. It is built for enormous throughput and near-zero fees, because scale was the whole point from the very beginning. It has native tokens, real smart contracts without the complexity of other platforms, and it keeps sound-money principles at its heart: a fixed supply and a fair launch.

In Conclusion

Nexa is the work of a team that has been in the room for almost the entire history of this technology, people who met as anonymous enthusiasts on a forum, who spent a decade proposing the future to Bitcoin, and who, when the answer was “not here”, went and built that future themselves. Nexa is the blockchain, built by a group of stubborn, patient, deeply experienced builders who always wanted Bitcoin to scale.

So the next time someone asks who is behind Nexa, you can tell them: it’s the people who were there from the start and who never stopped believing and helping this technology to grow.

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Sources & Useful Links

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Nexa is more than a blockchain—it’s a decade-long vision to scale Bitcoin’s original idea of peer-to-peer electronic cash.

:high_voltage: High scalability
:money_bag: Near-zero fees
:coin: Native tokens
:robot: Smart contracts
:pick: Proof-of-Work

Built from Bitcoin’s roots. Designed for the future.

#Nexa bitcoin #Crypto

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