# Tokens & fees
# Supported tokens
zkSync can be used to transfer ether (ETH) and ERC20 tokens. Initially, new tokens need to be manually whitelisted by the operator. In the future, adding new tokens will be fully permissionless.
The full list of currently supported tokens is available under this link (as JSON): https://api.zksync.io/api/v0.1/tokens.
DISCLAIMER: We will list any tokens fulfilling the criteria below on a first-come, first-serve basis. Listing of a token on zkSync does not represent an endorsement for this token by the Matter Labs team, Stichting ZK Sync, or any other entity. We do not have competence and authority to analyze the token business model and smart contract security guarantees of a particular token. Please use any token on your own risk and judgement.
# Listing a token
To submit token listing support, please fill out this form.
We can immediately list tokens that satisfy the following conditions:
- price tracked at https://coinmarketcap.com.
- daily trading volume exceeds $1M over the period of the past 3 months.
Tokens without sufficient liquidity or CMC price tracker will be listed as soon as we implement an option to pay fees in a different token (see below).
# Fee costs
In zkSync the cost of every transaction has two components:
- Off-chain part (storage + prover costs): the cost of the state storage and the SNARK (zero-knowledge proof) generation. This part depends on the use of hardware resources and is therefore invariable. Our benchmarks give estimates of ~0.001 USD per transfer.
- On-chain part (gas costs): for every zkSync block, the validator must pay Ethereum gas to verify the SNARK (~1.5k gas right now going down to a negligible amount with zkSync v1.1), plus additionally ~0.4k gas per transaction to publish the state ∆. The on-chain part is variable because it depends on the current gas price in the Ethereum network. However, this part is orders of magnitude cheaper than the cost of normal ETH/ERC20 transfers.
# How fees are payed
Transfers in zkSync support "gasless meta-transactions": users pay transaction fees in the tokens being transferred. Thus, for example, if you want to transfer DAI stable-coin, there is no need for you to own ETH or any other tokens. Just pay your fees in a fraction of DAI.
For tokens without a liquid market price, we will soon add an option to pay fees in a different token.