Bitcoin is the first cryptocurrency, the largest by market cap (over $1.46 trillion as of April 2026), and the reason every other project in this wiki exists. Someone using the name Satoshi Nakamoto published a nine-page white paper in 2008, launched the network in January 2009, and disappeared two years later. Nobody knows who they were. The network has run continuously since then, processing transactions without downtime for over 17 years.
What makes Bitcoin unusual among digital assets is how little it tries to do. It processes about 7 transactions per second. It has no smart contracts worth speaking of. It cannot run DeFi natively. And yet it remains, by a wide margin, the most valuable and most attacked blockchain in existence, with none of those attacks succeeding.
History and founding
Satoshi Nakamoto's white paper, "A Peer-to-Peer Electronic Cash System," went out to a cryptography mailing list on October 31, 2008. The timing was not accidental. Lehman Brothers had collapsed six weeks earlier. The paper proposed a way to send money without banks.
The network went live on January 3, 2009, when Satoshi mined the genesis block. Embedded in it was a headline from that morning's Times of London: "Chancellor on brink of second bailout for banks." Whether this was a political statement or a timestamp, nobody knows.
Early development was a small affair. Hal Finney, a cypherpunk and cryptographer, received the first Bitcoin transaction (10 BTC from Satoshi) on January 12, 2009. He would become one of Bitcoin's most important early contributors before his death from ALS in 2014. Satoshi communicated through forum posts and emails, handed project control to Gavin Andresen in 2010, and vanished. The estimated 1 million BTC in Satoshi's wallets have never moved.
For the first few years, Bitcoin was a curiosity for cryptographers and libertarians. The first commercial transaction most people cite is the famous pizza purchase in May 2010, when Laszlo Hanyecz paid 10,000 BTC for two Papa John's pizzas (those coins would be worth over $700 million today). Real mainstream attention came in 2013 when the price went from under $100 to over $1,000. The collapse of Mt. Gox in 2014, which lost 850,000 BTC in a hack, taught the industry an expensive lesson about centralized custody.
Since then, Bitcoin has gone through several boom-bust cycles. Each time, critics declared it dead. Each time, it came back at a higher price floor than the previous cycle's peak.
Technical architecture
How mining works
Bitcoin uses Proof of Work. Miners run SHA-256 hash computations, competing to find a value below a target difficulty. The first miner to find it gets to propose the next block and collect the reward. Difficulty adjusts every 2,016 blocks (roughly two weeks) to keep the average block time at ten minutes, regardless of how much or how little computing power the network has.
The security logic is straightforward: to rewrite Bitcoin's history, you would need to control more than half the network's hash power and sustain that control long enough to outpace the honest chain. As of 2026, Bitcoin's hash rate exceeds 500 exahashes per second. The electricity cost alone to mount a 51% attack would run into billions of dollars, with no guarantee of success. Nobody has tried.
Mining rewards halve every 210,000 blocks (about four years). The initial reward was 50 BTC per block. After the April 2024 halving, it dropped to 3.125 BTC. Daily issuance went from 900 BTC to 450 BTC. This schedule is hardcoded. No board, no committee, no vote can change it.
The 2024 halving played out differently than many expected. Block rewards fell 50%, but Bitcoin's price rose roughly 68% over the following year, so miners actually earned about 16% more in dollar terms despite the reduced subsidy. This is the mechanism working as designed: decreasing supply, increasing scarcity.
Performance and the scaling question
Bitcoin's base layer handles about 6.75 transactions per second. That is not a bug. Bitcoin's developers chose to keep blocks small (effectively 1-4 MB with SegWit) so that ordinary computers can run full nodes. The tradeoff is real: you get censorship resistance and decentralization, but you cannot process Visa-level transaction volumes on the base chain.
Transaction finality is probabilistic. The convention is to wait for six confirmations (about an hour) before treating a transaction as irreversible. That works fine for settlement but is obviously too slow for buying coffee.
The Lightning Network, proposed by Joseph Poon and Thaddeus Dryja in 2015, solves this by moving transactions off-chain. Two parties open a payment channel, transact as many times as they want with instant settlement, and close the channel with a single on-chain transaction. By early 2026, Lightning capacity passed 5,637 BTC, and monthly transaction volume exceeded $1 billion. Binance and OKX now support Lightning deposits and withdrawals.
The Taproot upgrade, activated in November 2021, brought Schnorr signatures and improved transaction privacy. Lightning Labs followed with Taproot Assets Protocol v0.7, which enables stablecoins and other assets to move over Lightning channels. This is significant: it means USDT and USDC could eventually settle over Bitcoin's payment infrastructure.
Smart contracts (or the lack of them)
Bitcoin Script is intentionally limited. It can handle conditional logic for spending (multisig, timelocks, hash locks), but it is not Turing complete. You cannot deploy a Uniswap on Bitcoin Script. This was a deliberate design choice to minimize the attack surface.
That said, two developments have expanded what Bitcoin can do. Ordinals, launched by Casey Rodarmor in January 2023, allow arbitrary data to be inscribed on individual satoshis (the smallest Bitcoin unit, 1/100,000,000th of a BTC). People have inscribed images, text, even small programs directly onto Bitcoin's blockchain. BRC-20, a token standard built on Ordinals, uses JSON inscriptions to create fungible tokens natively on Bitcoin. The ORDI token, the first major BRC-20 project, hit a market cap above $5 billion by 2026.
Stacks (STX) takes a different approach, offering Turing-complete smart contracts through the Clarity language while anchoring all settlement to Bitcoin. This gives you programmable DeFi with Bitcoin's security guarantees, though the tradeoff is additional complexity and a separate token.
Ecosystem and adoption
The "digital gold" narrative
Bitcoin started as "peer-to-peer electronic cash." It is now mostly described as "digital gold." The shift happened gradually as it became clear that 7 TPS and 10-minute blocks were never going to compete with Visa for daily payments. What Bitcoin does offer is a fixed supply of 21 million coins, no central issuer, and 17 years of uptime. For institutional investors, that is closer to gold than to a payment network.
The January 2024 spot Bitcoin ETF approvals made this narrative official. The SEC approved eleven spot Bitcoin ETPs on January 10, 2024. BlackRock, Fidelity, Grayscale, Bitwise, and others launched products that generated $4.6 billion in trading volume on day one. Pension funds, endowments, and family offices that could never hold Bitcoin directly now hold it through regulated ETFs.
MicroStrategy's corporate Bitcoin treasury (over 205,000 BTC) took this further, treating Bitcoin as a primary balance sheet asset rather than a speculative side bet.
Lightning Network as a payment rail
Lightning has grown from an experimental protocol to a functional payment network. The $1 billion monthly transaction volume in 2025 was real money moving through real channels. Tether invested $8 million in Lightning-focused startup Speed, signaling that stablecoin payments over Bitcoin's infrastructure are coming.
The user experience still needs work. Channel management, liquidity balancing, and routing failures remain friction points. But the trajectory is clear: Lightning processed more value in 2025 than some entire blockchain networks.
Ordinals and BRC-20
Ordinals changed the conversation about what Bitcoin is for. Before 2023, Bitcoin maximalists insisted the chain should only handle monetary transactions. Ordinals showed that people would pay significant fees to store data permanently on the most secure blockchain in existence. The BRC-20 token ecosystem that grew from Ordinals is still young and lacks the sophistication of Ethereum's ERC-20 infrastructure, but it proved that native token issuance on Bitcoin is possible without smart contracts.
Mining economics
Bitcoin mining has become an industrial operation. Marathon Digital Holdings, Riot Platforms, and Hut 8 Mining now control significant portions of the network's hash rate. Small-scale mining is mostly uneconomical unless you have access to very cheap electricity.
The 2024 halving forced weaker miners out. That is by design: difficulty adjusts downward when hash rate drops, keeping block times steady and allowing the remaining miners to stay profitable. The cycle of halvings, miner exits, difficulty adjustment, and price appreciation has repeated four times now. Each time, the mining industry emerges more consolidated and more efficient.
Energy consumption sits at about 173 TWh annually, comparable to Poland's electricity usage. The number is large but needs context. About 54% of Bitcoin mining now uses renewable energy, up from much lower figures in earlier years. Mining tends to cluster where electricity is cheap and abundant, often in places where surplus hydroelectric or geothermal power would otherwise go unused (Iceland, Paraguay, parts of Canada). The environmental debate has cooled somewhat since Ethereum's switch to Proof of Stake in 2022, which showed that not every blockchain needs to consume this much energy. Bitcoin's developers have no plans to change course.
Exchanges, wallets, and infrastructure
Bitcoin trades on hundreds of exchanges. The largest by volume is Binance, where BTC/USDT is the highest-volume pair on the platform. Coinbase dominates in the U.S. and is the preferred venue for institutional investors, partly because of its Coinbase Prime custody service. Kraken, founded in 2011, is known for thorough asset vetting and a focus on security. OKX and Bybit handle substantial derivatives volume.
For storage, the choice comes down to security versus convenience. Hardware wallets from Ledger and Trezor store private keys offline and are the standard for anyone holding significant amounts. Blue Wallet is the best mobile option with Lightning support. Electrum has been the power user's desktop wallet for years, with features like custom fee setting and hardware wallet integration.
Atomic swaps allow trustless peer-to-peer trading without exchanges, using timelocks and multisig to ensure both sides of a trade execute simultaneously or not at all. The technology works but has not achieved mainstream adoption.
Tokenomics
Bitcoin's supply schedule is the simplest in crypto. There will never be more than 21 million BTC. About 20.01 million have been mined. The final bitcoin will be mined around 2140. Block rewards halve every four years. No person or organization can change this.
An estimated 15-20% of all Bitcoin is permanently lost through forgotten passwords, dead hardware, or coins sent to unspendable addresses. Satoshi's estimated 1 million BTC has not moved in over 15 years. These lost coins reduce the effective circulating supply, making the remaining coins scarcer.
The long-term question is what happens when block rewards become negligible. Eventually, miners will depend entirely on transaction fees. Whether fee revenue alone can sustain enough mining to keep the network secure is an open question. Bitcoin bulls argue that rising BTC prices will make even small fees valuable enough. Skeptics point out that nobody has tested this at scale.
Governance and development
Bitcoin has no CEO, no foundation with veto power, and no formal governance structure. Changes to the protocol go through Bitcoin Improvement Proposals (BIPs). Developers propose, the community debates (often for years), and changes only activate when there is broad consensus among miners, node operators, and users.
The most contentious episode was the block size debate of 2015-2017. One camp wanted larger blocks to increase throughput. The other wanted to keep blocks small and scale through second layers. The disagreement resulted in the Bitcoin Cash fork in August 2017. Bitcoin kept its small blocks and added SegWit, which increased effective capacity without changing the block size limit.
Bitcoin Core development is maintained by a distributed group of contributors including Wladimir van der Laan, Marco Falke, and Gloria Zhao. The code review process is deliberately slow and conservative, prioritizing security over feature velocity.
Regulatory status
El Salvador adopted Bitcoin as legal tender in 2021. Most other countries treat it as property or a commodity. The U.S. Internal Revenue Service taxes Bitcoin as property, meaning every transaction can trigger capital gains reporting.
The most significant regulatory development came in March 2026, when the SEC and CFTC jointly classified Bitcoin as a digital commodity. This ended years of ambiguity and cleared the path for regulated financial products built on Bitcoin.
The EU's Markets in Crypto-Assets Regulation (MiCA), adopted in 2023, creates a comprehensive framework for crypto regulation across the bloc. Bitcoin survived a proposed proof of work mining ban that would have been far more restrictive.
Risks and open questions
Energy consumption. 173 TWh per year is a lot of electricity, and "54% renewable" still means 46% is not. Whether Bitcoin's security model justifies that cost depends on whether you think the network provides $1.46 trillion worth of value. Reasonable people disagree. Quantum computing. Shor's algorithm could theoretically break ECDSA, the signature scheme Bitcoin uses. Practical quantum computers capable of this are likely decades away, and Bitcoin can upgrade to quantum-resistant signature schemes when needed. Most bitcoin stored in P2PKH addresses (which hash the public key) has an extra layer of protection. This is a known risk with known mitigations. Volatility. Daily price swings of 5-10% are common. Annual swings exceeding 100% have happened repeatedly. This makes Bitcoin a poor medium of exchange for most purposes, though Lightning and stablecoin-over-Lightning may eventually change that. Base layer limitations. 7 TPS is not enough for a global payment network. Lightning helps, but Lightning adoption is still concentrated among technically savvy users. Whether it can reach mainstream usability is unproven.Recent developments (2025-2026)
The SEC approved eleven spot Bitcoin ETPs on January 10, 2024, generating $4.6 billion in first-day trading volume.
The April 2024 halving cut block rewards to 3.125 BTC. BTC price rose 68% over the following year.
Lightning Network capacity hit 5,637 BTC by late 2025. Monthly volume passed $1 billion.
Lightning Labs released Taproot Assets Protocol v0.7, enabling stablecoins on Lightning.
The SEC and CFTC jointly classified Bitcoin as a digital commodity on March 17, 2026.
ORDI's Binance listing in late 2025 triggered a wave of BRC-20 trading activity.