Summary

  • Approvals are required because Matcha is a decentralized exchange (DEX) that uses Ethereum smart contracts.
  • Approvals require a tiny amount of ETH to pay for the transaction's gas cost.
  • Approvals are needed once per token, per wallet address.

What is a token approval, and why is it necessary?

When using a decentralized exchange (DEX), like Matcha, you must first approve each token that you plan to trade. DEXs use smart contracts on the Ethereum blockchain to execute transactions. To use a smart contract, you must 1) permit it to validate your token balance, and 2) allow it to transfer the number of tokens that you wish to trade from your wallet.

As a real-life example, think of the token approval process similar to an artist (user) selling their artwork (token) in a gallery (Matcha). Before an artist can display their artwork at the gallery, the artist first needs to prove that they own it. Then both parties will sign a contract that gives the gallery permission to display and sell the artwork on behalf of the artist.

Matcha puts user safety first

Matcha uses the 0x protocol v3 smart contacts, which have been thoroughly tested by 0x Labs and top blockchain security companies, Trail of Bits, and ConsenSys Diligence. Learn more about the new exchange proxy here:

Matcha approval contracts

Matcha currently uses two different approval addresses depending on what type of trade you are about to make:

The Exchange Proxy address is 0xF740B67dA229f2f10bcBd38A7979992fCC71B8Eb and can be found on Etherscan here

The ERC20 Proxy address is 0x95E6F48254609A6ee006F7D493c8e5fB97094ceF and can be found on Etherscan here. We will be phasing out this address in the future.

Learn more

📚 Recommended reading to learn more about the ERC-2O standard and token approvals:

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