0x Protocol and ZRX Guide: Swap API, Settler and Governance Status

0x has evolved from the Ethereum relayer protocol described in this 2020 article into multichain trading infrastructure. Its current products include Swap API v2, Gasless API, a Solana Swap API and a Cross-Chain API. Integrators receive executable swap transactions while 0x aggregates decentralized-exchange and professional market-maker liquidity.

The old ZRX staking and governance description is no longer current. 0x’s June 2026 support guidance says the Exchange Proxy was effectively deprecated after the new Settler contracts arrived in 2024, protocol governance is dormant, and former stakers can withdraw through the legacy contracts. ZRX still exists as an ERC-20 token, but holding it does not currently produce the liquidity rewards described below.

Safety warning: A 0x quote is transaction data, not a guarantee of profit or execution. Verify the sell token, buy token, chain, amount, slippage, recipient, allowance target and transaction destination before signing. Never approve a token merely because a site claims to use 0x.

0x status in 2026

2020 feature	Current status
Protocol v3 and Exchange Proxy	Legacy architecture; Settler became the current execution design in 2024
ZRX market-maker staking pools	Retired; legacy stakers should use the vetted withdrawal route linked by 0x support
ZRX protocol governance	Dormant, according to 0x’s June 2026 support update
0x API	Current Swap API uses v2 endpoints and a unified API domain
Ethereum-only framing	Outdated; current swap support spans many EVM chains and a separate Solana API
Same-chain swaps only	Outdated; 0x now offers cross-chain quotes through multiple bridge providers
Matcha	Still a consumer-facing trading product powered by 0x infrastructure

How 0x works now

For a same-chain trade, an app requests an indicative price or firm quote. The API searches supported liquidity sources, calculates a route and returns transaction data for the user’s wallet to sign and submit. The user remains responsible for the token approval and the final transaction.

AllowanceHolder and Permit2 are distinct approval flows. An integrator must use the allowance target returned for the selected endpoint and should never request approval to the Settler execution contract itself. Unlimited allowances increase the damage a compromised app or approval target could cause.

The Cross-Chain API adds bridge and settlement providers to the route. This can combine a source-chain swap, bridge transfer and destination-chain delivery, but it also adds provider, message, finality, liquidity and recovery risks. Chain and provider coverage changes, so the live supported-chains table is the source of truth.

What is ZRX used for today?

ZRX was designed for protocol governance and earlier staking incentives. The maximum supply remains one billion, but the protocol’s dormant governance and retired staking system mean readers should not infer current cash flow, voting activity or yield from the historical token design.

A token can continue trading even when its original utility is inactive. Price, exchange availability and liquidity are market matters and should be checked independently from the status of 0x APIs or contracts.

Main 0x risks

Approval risk: a malicious or excessive ERC-20 allowance can outlive the intended trade.
Quote risk: price, gas, slippage and available liquidity can change before execution.
Token risk: fake, taxed, rebasing or nonstandard tokens can behave differently from an ordinary ERC-20.
Contract risk: routers, Settler, allowance systems and liquidity-source contracts can contain bugs.
Cross-chain risk: bridge providers and destination chains add failure and delay modes not present in a same-chain swap.
Integrator risk: a wallet or app can alter transaction details, fees or recipients even if it uses 0x for routing.
MEV risk: public transactions can be reordered or sandwiched, affecting execution.
Governance-token risk: ZRX’s historical utility does not guarantee future governance activation or token value.

Original September 2020 0x guide (historical archive)

The original author-written sections below are preserved substantially intact. Their version 3, relayer, product-suite, staking and governance descriptions reflect 2020. The obsolete external price-widget script was removed during the import cleanup.

0x ($ZRX) is an open protocol for developers to build their own decentralised cryptocurrency exchanges on the Ethereum blockchain. 0x came about as an answer to the problems inherent in centralised exchanges (CEX) and decentralised exchanges (DEX). For CEXs, approximately USD $1.1 billion has already been lost through security breaches on these platforms. Thus cryptocurrency enthusiasts have become wary for fear of losing their funds. Decentralised exchanges were meant to be an answer to this, but they have also issues of increased friction and increasing transaction costs. In this guide, we will explore what 0x is already offering in today’s market, and take a look at their recently released version 3 of the protocol.

Background

0x is a brainchild of its CTO, Amir Bandeali, and its CEO, Will Warren. Other key individuals behind the project include their blockchain engineers, product designers, researchers, and business strategists. They also have a strong list of advisors including Fred Ehrsam, Co-founder of Coinbase and David Sacks, former COO of PayPal.

What is 0x?

0x is a protocol built on the Ethereum blockchain to create and power decentralized exchanges. Its aim is to be interfaced with other systems to power high-end decentralized applications (dapps).

The protocol seeks to inspire the movement of assets across the financial sector by eliminating third parties that have been making the process complicated and costly. The presence of smart contracts has also helped push third parties further to oblivion.

The advent of DEXs comes to safeguard users’ funds and prevent government censorship. These exchanges place the security of users’ funds onto the users themselves instead of trusting centralized platforms, which are prone to hacks.

Due to the Bitcoin blockchain scalability issues and lack of smart contract flexibility, dapp developers have flocked to Ethereum to build decentralized solutions such as exchanges. Unfortunately, with everyone looking to build a specialized dapp, Ethereum has been flooded with applications that cannot communicate well with each other.

Furthermore, these applications have varying degrees of security and quality. 0x came to solve this user fragmentation issue, as well as reduce the cost of using dapps.

How does 0x work?

Although it is built on top of Ethereum, its orders are dealt with off-chain as relayers are used to match the orders. The orders are only uploaded on the Ethereum blockchain after the process is complete. Off-chain signing reduces the amount of gas used in a particular transaction while also reducing the load on the main chain.

A relayer on the platform can be thought of as a decentralized exchange that has both public and private order books. Orders are broadcasted through these order books to make a suitable match.

Apart from reducing the gas fees involved, this approach also allows users to have control over their funds. An important feature of a relayer is that it only facilitates but does not conduct trades.

To allow this, the relayer needs to be supplied with the order maker’s signature, which is then delivered to the DEX’s smart contract. Relayers are rewarded using the protocol’s native token, ZRX, though this has been changed along with several other features in version 3 of 0x.

0x version 3: A new protocol with enhanced features

In August 2020, the decentralized protocol released a new version 3 that enables users to develop a more interconnected DeFi ecosystem. There are 3 major upgrades in this new version: staking ZRX tokens, liquidity bridges and flexible fees.

0x staking features

Version 3 of 0x introduced a staking mechanism which allows trading fees to be accepted in any token. Market makers that provide liquidity are seen as crucial for 0x’s long-term growth since they bring in liquidity. Hence a new staking feature was introduced whereby market makers on 0x are given monetary rewards. This means that any ZRX holder can join a market maker’s staking pool and be entitled to a share of the liquidity rewards. Meanwhile, it is in the best interests of the market maker to entice stakers to join their pool because it increases their potential liquidity rewards payouts and their voting power on governance issues since stakers are required to delegate half their voting power to the market maker.

Liquidity bridges

Liquidity bridges is an exciting upgrade for decentralised finance (DeFi) developers who are building dapps that will benefit from accessing more liquidity. This is because the feature will enable them to source liquidity not only from the 0x network itself, but other DEXs such as UniSwap or Kyber from a single point of integration, known as 0x API (more on that below). In short, allowing users access to liquidity in other DEXs, thereby ensuring that orders are being filled to reach higher volumes, and thus attracting even more users onto the platform.

Flexible fees for Relayers

Previously, 0x only allowed Relayers to receive fees in ZRX only. This was problematic because sometimes Relayers may not want to receive fees in ZRX. It also led to a poor experience for Relayers since it created more additional steps in DEX trading, for example one of the largest 0x DEXs by volume didn’t have fees. And there is speculation that this is because of the limited ways in which fees could be paid out. This has been fixed in version 3, where Relayers can choose to have their fees paid in any Ethereum-based token or even in the token currently being traded.

ZRX Token: What is it?

The ZRX token is built based on Ethereum’s ERC-20 standard. Apart from being used to pay relayers for facilitating trades, it is also utilized for governance on the 0x protocol. In line with this, the amount of ZRX held determines the power a governor has when contributing to governance issues such as protocol upgrades.

The ZRX token supply is hard-capped at one billion. During its launch in 2017, half of the tokens were released and distributed to developers (15%), 0x (15%), founding team (10%), and advisors (10%).

ZRX is listed on Binance, Coinbase, Huobi, HitBTC, and other leading exchanges. For storage, the token is supported by Ledger (both the Nano X and Nano S), Enjin, Exodus, and any other cryptocurrency wallets primed for ERC-20 tokens.

As mentioned above, the 0x team has recently introduced staking features for ZRX which gives more incentives for both liquidity providing market makers and ZRX holders.

Other products powered by 0x

0x has a whole suite of products aside from its open protocol. These are:

· 0x Instant– This offers a way to buy cryptocurrency on any app or website.

· 0x mesh – Allows access to a global P2P order book for tokens.

· 0x API – Can be used to accumulate liquidity from platforms built on the protocol such as UniSwap, and Mesh. It can also be used to swap tokens based on price.

· Matcha – A platform to find the best prices across exchange networks.

· 0x Extensions – For use with relayers to incorporate new trading types.

· 0x OTC – This is a consumer-based exchange that allows for a P2P exchange of ETH tokens without a relayer. Unlike the other P2P exchanges, 0x OTC enables the seller to send a link to the buyer on any platform, including social media, and its results are recorded on the Ethereum blockchain.

Even with numerous advantages, the protocol uses multi-signature smart contracts that could be exploited since they are still based on code. Also, since the DEXes are still a work in progress, they may not have the liquidity needed to fill orders for lesser-known tokens.

Conclusion

As blockchain technology matures, so should the applications run on top of it. However, as more dapps flood the scene, we need a standard quality and security setting to ensure that these systems operate as they are intended. Thankfully, with 0x, the standard is already set.

Furthermore, dapp developers also need to embrace the system for users to benefit from low transaction fees.

The 0x protocol can be used in prediction markets such as sports betting, which require untampered results of outcomes of physical events.

The platform’s vast use cases are also capable of bringing real change in the decentralized world while leveraging off-chain mechanisms to drastically enhance scalability.

Decentralised Finance (DeFi) series: tutorials, guides and more

With content for both beginners and more advanced users, check out our YouTube DeFi series containing tutorials on the ESSENTIAL TOOLS you need for trading in the DeFi space e.g. MetaMask and Uniswap. As well as a deep dive into popular DeFi topics such as decentralized exchanges, borrowing-lending platforms and NFT marketplaces

The DeFi series on this website also covers topics not explored on YouTube. For an introduction on what is DeFi, check out Decentralized Finance (DeFi) Overview: A guide to the HOTTEST trend in cryptocurrency

Tutorials and guides for the ESSENTIAL DEFI TOOLS:

More videos and articles are coming soon as part of our DeFi series, so be sure to SUBSCRIBE to our Youtube channel so you can be notified as soon as they come out!

Disclaimer: Cryptocurrency trading involves significant risks and may result in the loss of your capital. You should carefully consider whether trading cryptocurrencies is right for you in light of your financial condition and ability to bear financial risks. Cryptocurrency prices are highly volatile and can fluctuate widely in a short period of time. As such, trading cryptocurrencies may not be suitable for everyone. Additionally, storing cryptocurrencies on a centralized exchange carries inherent risks, including the potential for loss due to hacking, exchange collapse, or other security breaches. We strongly advise that you seek independent professional advice before engaging in any cryptocurrency trading activities and carefully consider the security measures in place when choosing or storing your cryptocurrencies on a cryptocurrency exchange.

Frequently asked questions

What is 0x Protocol?

0x is on-chain trading infrastructure that aggregates liquidity and returns executable swap transactions to apps, wallets and other integrators.

Is 0x itself a decentralized exchange?

0x supplies contracts, routing and APIs used by trading interfaces. Matcha is a consumer interface, while many other wallets and apps integrate 0x behind their own user experience.

What replaced 0x Protocol v3?

0x progressed through v4 and deployed its newer Settler execution contracts in 2024. The old Exchange Proxy and v3 staking discussion in this article is historical.

Is ZRX staking still active?

No. The former market-maker staking program is a legacy system. 0x support points prior stakers to a vetted community withdrawal guide.

Is 0x governance active?

0x's June 2026 support guidance describes protocol governance as dormant after the Settler transition and says near-term reactivation is unlikely without a compelling reason.

What is ZRX used for?

ZRX historically powered governance and staking. It remains a traded ERC-20 token, but those historical functions do not currently provide active protocol governance or staking rewards.

Which chains does 0x support?

0x supports many EVM networks, a separate Solana swap product and a broader set of cross-chain origins and destinations. Because coverage changes, check the live supported-chains documentation.

What is the 0x Cross-Chain API?

It returns routes and ready-to-sign transactions that can combine swaps and transfers through supported bridge providers, with status tracking after submission.

Does a 0x quote guarantee the final amount?

No. Liquidity, gas, token behavior, slippage, block conditions and transaction timing can affect execution or cause a revert.

What should I verify before signing a 0x swap?

Verify the network, tokens, units, amount, minimum received, recipient, fee, allowance target and transaction destination. Revoke allowances that are no longer needed.