0x Protocol
zrxWhat is 0x Protocol?
0x Protocol is an open-source trading infrastructure project founded around trust-minimized exchange of Ethereum-based assets. Its live product is now a suite of developer APIs: Swap for aggregated liquidity and executable transactions, Gasless for sponsored transactions, Trade Analytics, and cross-chain quoting/status services. The 0x docs describe makers supplying liquidity and takers submitting trades that are checked and settled atomically on-chain.
ZRX is the protocol's Ethereum ERC-20 token at 0xE41d2489571d322189246DaFA5ebDe1F4699F498. Earlier 0x designs emphasized off-chain order dissemination, relayers and a governance role for ZRX; later specifications document staking, liquidity rewards and ZEIP voting. Those documented token utilities should not be conflated with a claim that current Swap API customers need ZRX.
What problem does 0x Protocol solve?
The original 0x problem was fragmented Ethereum-token liquidity and the cost of building a decentralized exchange: makers could publish signed orders off-chain while takers settled trades on-chain without depositing assets with a centralized operator. The current problem is broader and productized: developers need one integration to search fragmented liquidity, route swaps, sponsor gas, and execute across supported chains.
0x's own historical account records a 2020 expansion from protocol infrastructure into products built on top of it, including Swap API and Matcha. Current docs describe a multi-source routing and settlement service, while the old relayer-centric architecture is useful history rather than a complete description of today's API.
How does 0x Protocol work?
A current integration requests a quote or instruction from the 0x API, receives transaction data and an allowance target, and has the user or application sign and submit the resulting transaction. The routing engine aggregates on-chain and off-chain liquidity; 0x Settler/AllowanceHolder or Permit2 contracts then enforce conditions and atomically exchange assets. The docs explicitly warn integrators not to approve the Settler contract and say entry-point addresses can change with deployments.
ZRX is a conventional ERC-20 with 18 decimals and a 1,000,000,000-token supply minted to the deployer in its constructor. The staking specification says staked ZRX can provide liquidity-reward eligibility and governance voting, with one staked ZRX equal to one vote. That specification also describes upgradeable staking logic and governor-authorized exchange/parameter management. The ZRX token contract itself exposes no mint, pause, blacklist or proxy-upgrade entry point in the published source; staking/admin controls are separate contracts and should not be attributed to the token contract.
Key facts
- Canonical ZRX contract: 0xE41d2489571d322189246DaFA5ebDe1F4699F498 on Ethereum; Etherscan marks the source as verified and names the contract ZRXToken.
- The published ZRX source sets 18 decimals and totalSupply to 10**27 base units (1,000,000,000 ZRX), assigning the entire initial balance to the deployer in the constructor.
- The current 0x product is API infrastructure: Swap, Gasless, Trade Analytics and cross-chain APIs, rather than a standalone chain with ZRX as its native gas token.
- The current docs describe aggregation from many liquidity sources and atomic on-chain settlement through 0x Settler plus AllowanceHolder or Permit2 approval paths.
- The staking specification documents staked-ZRX liquidity incentives and ZEIP governance, with one staked ZRX equal to one vote; this is a separate staking/governance system from the basic ERC-20 transfer contract.
- The token source and deployed ABI expose standard ERC-20 operations only; no public mint, pause, blacklist or upgrade function is shown for the ZRX token itself.
- 0x's February 2021 historical announcement says the organization expanded in 2020 from protocol infrastructure into Swap API, Matcha and v4, so historical protocol architecture and current commercial products should be read separately.
Official links
Categories
Related coins
Frequently asked questions
Is 0x a blockchain or an exchange?
Neither in the usual sense. 0x is open trading infrastructure and a set of APIs/contracts that applications use to aggregate liquidity and settle swaps on existing chains. Matcha was a consumer product built on top of that infrastructure, not the same thing as the 0x protocol.
What rights does a ZRX holder have?
The staking specification documents utility for staked ZRX: liquidity-reward participation and voting on ZEIPs, with one staked ZRX equal to one vote. ZRX does not, on the cited evidence, represent equity, a guaranteed revenue share, a claim on reserves, or ownership of 0x Labs or its products.
What is ZRX's supply and can the token owner mint more?
The published ZRXToken source sets a 1,000,000,000 ZRX total supply with 18 decimals and assigns it at deployment. Its public functions are standard ERC-20 functions; no mint function is present in that source. Future contract migrations or separate staking contracts are a different risk surface and do not change the cited token contract's interface.
Do current 0x API users need to hold ZRX?
Not according to the current API documentation. The current integration flow uses API keys, quotes, allowance targets and settlement contracts; it does not state a ZRX holding requirement. ZRX utility is documented mainly through the separate staking/governance design.
Can 0x contracts be upgraded or have their addresses changed?
The current docs say Settler entry-point addresses are dynamic and should not be hardcoded, and the staking specification describes upgradeable staking logic under governor authorization. Integrators must obtain current addresses from API responses or official registries and review governance/admin controls rather than assuming every deployed component is immutable.
External trackers
Choose a tracking site for 0x Protocol: