Sonic is an EVM-compatible Layer 1 blockchain built by the team behind Fantom. It isn't just a new name for the old network: Sonic is a new chain, with a rewritten client and a new native token, S, which replaced FTM through a 1:1 upgrade. If you knew Fantom, the short version is: same developers and consensus lineage, new chain, new token, and a few features aimed specifically at app developers.
Where it came from: Fantom and Lachesis
Fantom's mainnet, Fantom Opera, launched in 2019. Its distinguishing feature was Lachesis, a consensus protocol with two unusual properties:
- Leaderless. Instead of one validator proposing each block, every validator creates events and shares them. Events reference earlier events, forming a directed acyclic graph (DAG) rather than a single chain. Blocks are derived from the DAG once enough validators have seen the same events.
- Asynchronous Byzantine fault tolerant (aBFT). It stays safe as long as fewer than a third of validators by stake are faulty, without assuming messages arrive within a fixed time. Once a block is final, it's final: there are no probabilistic confirmations or reorgs to wait out.
That gave Fantom fast finality, around a second, at a time when that was rare among EVM chains. It became a popular home for DeFi experiments during 2021, but its client inherited much of its storage and execution design from Ethereum's Geth, which limited how far performance could be pushed.
The move to Sonic
The Fantom Foundation rebranded as Sonic Labs in 2024, and Sonic's mainnet launched in December 2024. The key differences:
| Fantom Opera | Sonic | |
|---|---|---|
| Native token | FTM | S |
| Consensus | Lachesis aBFT | Lachesis-derived aBFT |
| Client | Go-Opera, based on Geth | A new client with its own database and EVM implementation |
| Ethereum bridge | Third-party bridges | Native Sonic Gateway |
| Developer revenue | None at protocol level | Fee Monetization |
FTM holders could upgrade to S at a 1:1 ratio through the official upgrade portal, and major exchanges handled the conversion for balances they held. The details of the upgrade path, such as which routes remain open and whether any deadlines apply, have changed over time, so check Sonic's official documentation before moving old FTM. Be wary of "migration" sites you reach through ads or direct messages; token upgrades attract phishing.
What the new client changes
The Sonic client replaces the parts of the stack that limited Opera:
- A new state database designed to store only what's needed and keep it compact, reducing disk usage substantially compared with the Geth-style layout.
- A new EVM implementation, rewritten for speed while staying compatible with Ethereum's semantics.
- Tuned networking and consensus for faster block production.
Sonic Labs has cited figures such as around 10,000 transactions per second and sub-second finality. Treat those as the project's own benchmarks: real throughput depends on what the transactions do, and published numbers have been revised as the network evolved. What's well established is that Sonic keeps Lachesis's key property: finality is deterministic and fast, not probabilistic.
Fee Monetization
Fee Monetization (FeeM) is the feature most likely to matter to developers. On most chains, gas fees go to validators or are burned, and the app that generated the activity earns nothing from them. On Sonic, a registered app can receive a share of the network fees paid by transactions that interact with its contracts. The headline figure is up to 90% of those fees.
In practice:
- You register your contracts for the program and are subject to approval, which is meant to filter out apps that exist only to farm fees.
- Rewards are based on the gas your contracts actually consume, and are paid out in S.
- Since fees are small per transaction, it's meaningful mainly for apps with steady, high usage.
The idea is similar to how app stores or ad networks pay publishers: it gives developers an ongoing revenue stream tied to real usage rather than relying only on a token launch.
The Sonic Gateway
The Sonic Gateway is the native bridge between Ethereum and Sonic, run as part of the protocol rather than by a third party. It's how assets such as USDC and WETH move from Ethereum onto Sonic.
Two properties are worth knowing:
- Batched transfers. Deposits and withdrawals aren't processed instantly. They're relayed in periodic batches, so a transfer can take anywhere from minutes to about an hour depending on direction and timing. If you pay a small extra fee, you can trigger a batch sooner.
- A fail-safe. If the Gateway stops operating for an extended period (the documented window is around 14 days), users can reclaim bridged assets on the origin chain. That's a meaningful protection, since bridges are among the most attacked components in crypto, but it doesn't make the bridge risk-free.
EVM compatibility
Sonic runs the EVM, so for developers it behaves like other EVM chains:
- Solidity and Vyper contracts deploy without changes.
- Hardhat, Foundry, ethers.js, viem and wallets such as MetaMask work by adding Sonic's RPC endpoint and chain ID from the official docs.
- Accounts, signatures and addresses are standard Ethereum format, so the same private key controls the same address on Sonic.
- Gas is paid in S, not ETH. A contract that expects the native token to be ETH, or that hard-codes Ethereum token addresses, needs to be adjusted.
A Foundry deployment looks the same as on any other EVM chain:
forge create src/Counter.sol:Counter \
--rpc-url "$SONIC_RPC_URL" \
--private-key "$PRIVATE_KEY" \
--broadcast
Fantom Opera contracts don't carry over automatically. Sonic is a separate chain, so existing Opera contracts must be redeployed, and their state (balances, positions, NFTs) migrated by the project if it chooses to.
What holders should know
- FTM and S are different tokens on different chains. If you still hold FTM on Opera, use the official upgrade path rather than sending it to a Sonic address.
- Staking works through validators with delegation, as on Fantom. Delegated stake can be subject to lock-ups and unbonding periods, so read the terms before staking.
- Bridged tokens carry bridge risk. USDC moved over the Gateway is a bridged representation backed by assets on Ethereum, and it depends on the Gateway working correctly.
- Finality is fast. Exchanges and apps can credit deposits sooner than on chains with probabilistic finality.
Summary
| Question | Answer |
|---|---|
| Is Sonic the same chain as Fantom? | No. It's a new chain from the same team, with a new client. |
| What happened to FTM? | It was upgradable 1:1 to S; check the official docs for current options. |
| What consensus does it use? | An aBFT design descended from Fantom's Lachesis, with fast, final blocks. |
| What's new for developers? | Fee Monetization, the native Sonic Gateway to Ethereum, and higher throughput. |
| Do Ethereum tools work? | Yes. It's EVM-compatible; gas is paid in S. |
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