The landscape of the blockchain and cryptocurrency world at the beginning of 2021 was dramatically different from what it is today. On Dec. 31, 2020, the entire crypto market cap was at US$750 billion, compared to about US$2 trillion this month, and less than what Bitcoin alone is worth right now, according to data from CoinMarketCap.

One constant remained, however: the two cryptocurrencies at the top of the list by market cap. Bitcoin remains in the number one spot, and Ethereum, in second position, is the undisputed king of decentralized apps (dApps) and smart contract functionality. But also in 2021, a few blockchains dubbed “Ethereum killers” that fancy themselves as contenders to Ethereum’s crown emerged and started making serious jousts for Ethereum’s title.

Stepping away from the crypto market tumult, let’s take a look back and examine the top five rivals to Ethereum this year.

Binance Smart Chain — BNB

Launched only a year ago by the world’s leading crypto exchange Binance, the Binance Smart Chain is a smart contract enabled blockchain running in parallel with the Binance Chain that is also compatible with the Ethereum Virtual Machine. Its popularity skyrocketed in April this year as daily transactions on the network surpassed those on Ethereum by over 500%, reaching over 9 million transactions for the day compared to Ethereum’s 1.5 million.

Transaction numbers for both networks dropped significantly with the May crash earlier this year. But while Ethereum has yet to reach those heights again, BSC has only continued to grow, reaching a new daily record of over 16 million transactions in late November, according to BSCScan.

During this time, just one decentralized exchange, PancakeSwap, was responsible for more transactions on BSC than on the entire Ethereum network. In May, the total value of assets locked in DeFi protocols reached a peak of over US$30 billion, though it fell sharply soon after and has not yet recovered to nearly that point. It was sitting at just over US$16 billion at press time, according to DeFi Llama.

Binance Coin — the native token of the Binance blockchain ecosystem, which includes BSC, Binance Chain, Binance Academy, Trust Wallet and Research projects — began the year in ninth position in the crypto top 10 by market cap, trading around US$37 with a market cap of US$5.3 billion. Binance Coin is now firmly in third position, trading around US$580 with a market cap of almost US$100 billion, according to CoinMarketCap.

Solana — SOL

Solana was arguably the hottest blockchain in the second half of this year after the successful launch of its cross-chain communication bridge Wormhole and its own NFT series Degenerate Ape Academy that sold out its 10,000 units in eight minutes after launch, generating trading volume in excess of US$2.5 billion.

Solana uses a combination of two consensus mechanisms: proof of stake, which rewards validators with its native token SOL in accordance with how much the validators have staked into the network, and proof of history, which keeps a record of historical transactions so the network can order and track them faster. Using this combination of consensus mechanisms improves Solana’s throughput to the point where it is now capable of around 65,000 transactions per second, 2,000 times faster than Ethereum and 40 times faster than Visa.

This also makes the Solana network one of the more energy-efficient blockchains; a recent report released by Solana Labs, the company behind the blockchain revealed that a single transaction on the network uses 1,837 joules of energy, while a Google search uses 1,080 J. For comparison, even with its dramatically reduced energy costs, a transaction on ETH2 would still require 126,000 J.

In August, following the launch of the Degenerate Ape series, Solana’s SOL was trading at only US$64.48 but has gone on to break new ground several times since hitting its most recent all-time high of US$260 in early November. With a market cap of around US$55 billion around press time, Solana was sitting in the fifth position in the crypto top 10, according to CoinMarketCap.

Cardano — ADA

With one of the co-founders of Ethereum, Charles Hoskinson, as Cardano’s founder and driving force, Cardano was destined to be part of this list since its start. A proof-of-stake blockchain, Cardano was for a time the third-largest blockchain in the world, almost topping US$100 billion in market cap in September when its native token ADA reached its all-time high of US$3.10, according to CoinMarketCap.

Cardano ADA’s price action was in response to an August announcement that the network’s long-awaited “Alonzo” upgrade was coming to the network, bringing with it smart contract capabilities, support for NFTs and an ERC-20 converter, which would allow Ethereum tokens to run on the network.

Since the upgrade, however, Cardano has struggled to maintain its position in the crypto top 10 lists, with ADA losing almost 60% of its value since its all-time high in September, to be trading around US$1.30 at press time.

Upgrades to the Cardano network are notoriously slow due to a culture of academic rigor that the IOHK team applies to the network — subjecting any proposals to a process of peer-reviewed research. The Cardano network is also being used by the agricultural industry to better track supply chains, as well as the Ethiopian Ministry of Education which is deploying the network to track academic credentials in a tamper-proof way.

Avalanche — AVAX

The Avalanche network had a strong finish to the year after its native AVAX briefly broke into the crypto top 10 in mid-November to reach its all-time high of US$146.22 — knocking out Dogecoin to leave the top 10 list devoid of memecoins since Dogecoin’s rise in April. AVAX has since retreated from that position, to be trading around US$90 at press time, sitting just outside the top 10 in 12th position.

This marks a significant gain for the AVAX network which started the year in 24th position with a market cap of only a third of its current US$22 billion, according to CoinMarketCap.

Following a mainnet launch in 2020, Avalanche has worked to expand its ecosystem of dApps and DeFi, while allowing Ethereum-based projects such as SushiSwap and TrueUSD to operate on the system. Capable of supporting 6,500 transactions per second without compromising scalability, Avalanche actually consists of three individual blockchains, X-Chain, C-Chain and P-Chain, each with a specific purpose and relying on separate consensus mechanisms.

Exchange chain (X-Chain) creates and exchanges the native AVAX token and other assets, and uses the Avalanche consensus mechanism — a process whereby all transactions are processed simultaneously and uses random polling to ensure that transactions are correct with statistical certainty. There are also no blocks in this mechanism, dramatically improving speeds.

The Contract chain (C-Chain) hosts smart contracts and dApps, and uses its own Avalanche Virtual Machine, similar to the EVM, allowing developers to fork EVM-compatible dApps, while the Platform chain (P-Chain) coordinates network validators and tracks and allows for the creation of new subnets.

Polkadot — DOT

Described as a “next-generation blockchain” by its developer, Polkadot allows different blockchains to transfer value in a trustless fashion while using only one secure channel. Launched only in May last year by another ex-member of the Ethereum team, Gavin Wood, the network initially used a proof of authority consensus mechanism, which relies on known and reputable validators to produce blocks, but this was quickly abandoned in favor of a proof of stake model a few months later.

Running a series of parachains on the network in conjunction with the main Relay chain of the network, its developers hope this approach will allow developers to create and roll out new projects easily and affordably.

Moving with the rest of the market towards the end of the year, Polkadot’s native token DOT reached a new all-time high of US$55 in early November while its market cap topped US$50 billion. Unfortunately, the market-wide sell-off in mid-December saw the blockchain lose quite a bit of ground over that time and was trading around US$27 at press time, with a market cap almost half of what it was at its peak, according to CoinMarketCap.

Looking forward to Ethereum 2.0

At the beginning of the year, Bitcoin’s market dominance — the percentage of the total market capitalization that it controls — was just under 70%, while Ethereum’s was just under 13%. Bitcoin’s dominance has continued to fall throughout the year, however, and Ethereum’s has grown, and they now represent roughly 40% and 20% respectively, according to CoinMarketCap.

Ethereum’s been making steady ground by this metric all year and is likely to continue with the highly anticipated rollout of Ethereum 2.0. But as new technologies and use cases continue to be developed, nothing is certain as we move into the future, except that the race to find the “Ethereum Killer” blockchain will be closely watched indeed.