Do you want to swap 10 DAI for ETH? Sure thing, we'll just need your approval to spend a BAJILLION DOLLARS!

Do you ever feel worried about the different apps that have access to the tokens in your wallet? revoke.cash allows you to inspect all the contracts you've approved to spend money on your behalf, and revoke their access for the ones you no longer need. If you don't want to completely revoke access, it's also possible to update the amount they are allowed to spend instead.

If you want to learn more about (unlimited) token approvals, I wrote an article on my blog: Unlimited ERC20 allowances considered harmful.

Running locally

git clone [email protected]:rkalis/revoke.cash.git
cd revoke.cash
yarn
yarn dev

Environment variables

An .example.env file is provided that needs to be copied into a .env file and filled out.

Some of these variables are integral to the functioning of Revoke.cash:

• NEXT_PUBLIC_INFURA_API_KEY is used for reading data from Ethereum + Testnets.
• NEXT_PUBLIC_ALCHEMY_API_KEY is used for reading data from Polygon, Optimism and Arbitrum + Testnets
  • Alchemy is also used for ENS and UNS name resolutions - if omitted those resolutions will not work.
• COVALENT_API_KEY and COVALENT_IS_PREMIUM is used for certain chains such as Evmos and Harmony.
• ETHERSCAN_API_KEYS and ETHERSCAN_RATE_LIMITS are used for many of the other chains such as BNB Chain or Avalanche.
• NEXT_PUBLIC_NODE_URLS is used to override any RPC URLs on the frontend - e.g. if you want to use Alchemy instead of Infura.
• NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID is used for WalletConnect - if omitted, WalletConnect will not work.

If you omit any of these variables, Revoke.cash will not work for the chains you omitted.

Then there are a few less essential variables:

• IRON_SESSION_PASSWORD is used for encrypting session cookies and can be filled with any random 32-character string - if omitted many chains will not work.
• NEXT_PUBLIC_AMPLITUDE_API_KEY is used for Analytics - if omitted, no Analytics are collected.
• UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN are used for queueing third-party API calls - these are only necessary when hosting in a serverless environment such as Vercel.
• NEXT_PUBLIC_HARPIE_API_KEY is used to call Harpie's API for getting contract address labels - if omitted it only uses public label data sources.
• NODE_URLS is currently unused, but can be used for certain networks in the future.
• LOCALAZY_API_KEY is used for generating "Help Us Translate This Page" links - if omitted, those links will not work.

Contributing

Adding a new network

Adding a new network is relatively straightforward as you only need to change two files: lib/utils/chains.ts and cypress/e2e/chains.cy.ts.

Prerequisites

To add a new network, one of the following needs to be available:

• A (public or private) RPC endpoint that supports eth_getLogs requests for the entire history of the network.
• Support in CovalentHQ for the network.
• A block explorer with an exposed API that is compatible with Etherscan's API (such as Blockscout).

Also make sure that your network is listed in ethereum-lists/chains (and that it has subsequently been included in @revoke.cash/chains). Besides the earlier requirements, we also require a publicly available RPC endpoint with rate limits that are not too restrictive. It is also helpful if your network is listed (with TVL and volume stats) on DeFiLlama, but this is not required.

Adding the network

In lib/utils/chains.ts:

• Add the network to PROVIDER_SUPPORTED_CHAINS, BLOCKSCOUT_SUPPORTED_CHAINS, ETHERSCAN_SUPPORTED_CHAINS or COVALENT_SUPPORTED_CHAINS.
• Add the network to CHAIN_SELECT_MAINNETS or CHAIN_SELECT_TESTNETS. You can subsequently run yarn ts-node scripts/get-chain-order.ts to determine its position in the network selection dropdown.
• Find a logo (preferably svg) for the network, add it to public/assets/images/vendor/chains and add the path to getChainLogo().
• If multicall3 is deployed on the network, add it to getChainDeployedContracts().
• If a price source (Uniswap v2 or Uniswap v3 fork) is available for the network, add it to getChainPriceStrategies().
• If it uses a block explorer API such as Etherscan's or Blockscout's, add the network to getChainApiUrl() and if it requires an API key, this should be added to the environment variable ETHERSCAN_API_KEYS in .env.
• If the data in ethereum-lists/chains is different than what should be used by Revoke.cash, add the network to getChainName(), getChainExplorerUrl(), getChainRpcUrl(), getChainFreeRpcUrl(), getChainLogsRpcUrl(), getChainNativeToken()
• Add an amount to getDefaultDonationAmount() that corresponds to around $10-20 in the native token of the network.

In cypress/e2e/chains.cy.ts:

• Find a wallet that has active approvals and add it to fixtures.

Credits

Website created by Rosco Kalis after discussing the idea with Paul Berg at Devcon 5 in Osaka. Uses ethers.js and wagmi for all Ethereum-related operations and Etherscan, CovalentHQ, Infura & Alchemy for extended multichain support. Built with Next.js, Tailwind and TypeScript. Uses Upstash for queueing.