# Set Token Pool rate limits using Foundry Source: https://docs.chain.link/ccip/tutorials/evm/cross-chain-tokens/update-rate-limiters-foundry Last Updated: 2025-10-22 > For the complete documentation index, see [llms.txt](/llms.txt). This tutorial will guide you through the process of updating the rate limiter settings for outbound and inbound transfers in your deployed token pools using [Foundry](https://book.getfoundry.sh/). You will first review existing rate limiter settings and then update them. ## Prerequisites - **Tokens and pools deployed**: Ensure that you have tokens and token pools already deployed on both networks you plan to use. If not, refer to one of the following tutorials: - [Register from an EOA (Burn & Mint)](/ccip/tutorials/evm/cross-chain-tokens/register-from-eoa-burn-mint-hardhat) - [Register from an EOA (Lock & Mint)](/ccip/tutorials/evm/cross-chain-tokens/register-from-eoa-lock-mint-hardhat) - **Admin access**: Ensure you have the necessary privileges to call the [setChainRateLimiterConfig](/ccip/api-reference/evm/v1.6.1/token-pool#setchainratelimiterconfig) function for your token pools. ## Before You Begin 1. Make sure you have Node.js v22.10.0 or above installed. If not, **install Node.js v22.10.0**: [Download Node.js v22.10.0](https://nodejs.org/en/download/) if you don't have it installed. Optionally, you can use the [nvm package](https://www.npmjs.com/package/nvm) to switch between Node.js versions: ```bash nvm use 22 ``` Verify that the correct version of Node.js is installed: ```bash node -v ``` Example output: ```bash $ node -v v22.15.0 ``` 2. **Install Foundry**: If you haven't already, follow the instructions in the [Foundry documentation](https://book.getfoundry.sh/getting-started/installation) to install Foundry. 3. **Clone the repository and navigate to the project directory**: ```bash git clone https://github.com/smartcontractkit/smart-contract-examples.git cd smart-contract-examples/ccip/cct/foundry ``` 4. **Set up your environment**: Create a `.env` file by copying the `.env.example` file, and fill in the required values: ```bash cp .env.example .env ``` Example `.env` file: ```bash PRIVATE_KEY= RPC_URL_FUJI= RPC_URL_ARBITRUM_SEPOLIA= ``` Variables to configure: - PRIVATE\_KEY: The private key for your testnet wallet, **must** begin with `0x`. If you use MetaMask, you can follow this [guide](https://support.metamask.io/managing-my-wallet/secret-recovery-phrase-and-private-keys/how-to-export-an-accounts-private-key/) to export your private key. **Note**: This key is required for signing transactions like token transfers. - RPC\_URL\_FUJI: The RPC URL for the Fuji testnet. You can get this from the [Alchemy](https://www.alchemy.com/) or [Infura](https://infura.io/) website. - RPC\_URL\_ARBITRUM\_SEPOLIA: The RPC URL for the Arbitrum Sepolia testnet. You can get this from the [Alchemy](https://www.alchemy.com/) or [Infura](https://infura.io/) website. 5. **Load the environment variables** into the terminal session where you will run the commands: ```bash source .env ``` 6. **Install dependencies**: ```bash forge install && npm install ``` 7. **Compile the contracts**: ```bash forge build ``` 8. **Fund your EOA with native gas tokens**:\ Make sure your EOA has enough native gas tokens on Avalanche Fuji to cover transaction fees. You can use the [Chainlink faucets](https://faucets.chain.link/) to get testnet tokens. > **NOTE: Using Different Networks** > > This tutorial uses Avalanche Fuji and Arbitrum Sepolia by default. To test with other CCIP-supported networks, see > [Add CCIP Networks for Cross-Chain Token > Tutorials](/ccip/tutorials/evm/cross-chain-tokens/configure-additional-networks-foundry). ## Tutorial > **NOTE: Explore the Code** > > All Foundry scripts used in this tutorial are located in the `script/` directory of the repository. Each script is > thoroughly commented and directly linked to a key step in the tutorial, making the code self-explanatory. Read the > code and comments to gain a deeper understanding of the process or explore the implementation details. ### Review current rate limiter settings Use the `GetCurrentRateLimits` script to fetch the current rate limiter states for a specific chain from a token pool. This script provides detailed information about both inbound and outbound rate limits, including: - Whether rate limiting is enabled - The maximum capacity (bucket size) - The refill rate (tokens per second) - Current token amount in the bucket - Last update timestamp ```bash forge script ./script/GetCurrentRateLimits.s.sol:GetCurrentRateLimits \ --rpc-url \ --sig "run(address,uint256)" -- \ ``` 1. **Check the current configuration for Avalanche Fuji**: Replace `` with `$RPC_URL_FUJI`, `` with your token pool address on Avalanche Fuji, and `` with the Arbitrum Sepolia chain ID (`421614`). Example: ```bash forge script ./script/GetCurrentRateLimits.s.sol:GetCurrentRateLimits \ --rpc-url $RPC_URL_FUJI \ --sig "run(address,uint256)" -- \ 0xeB841acbc25549D4deB6Ed9401f3CbB529F3DC3e 421614 ``` Expected output: ```bash == Logs == Rate Limiter States for Chain Selector: 3478487238524512106 Pool Address: 0xeB841acbc25549D4deB6Ed9401f3CbB529F3DC3e Outbound Rate Limiter: Tokens: 0 Last Updated: 1747303192 Enabled: false Capacity: 0 Rate: 0 Inbound Rate Limiter: Tokens: 0 Last Updated: 1747303192 Enabled: false Capacity: 0 Rate: 0 ``` 2. **Check the current configuration for Arbitrum Sepolia**: Replace `` with `$RPC_URL_ARBITRUM_SEPOLIA`, `` with your token pool address on Arbitrum Sepolia, and `` with the Avalanche Fuji chain ID (`43113`). Example: ```bash forge script ./script/GetCurrentRateLimits.s.sol:GetCurrentRateLimits \ --rpc-url $RPC_URL_ARBITRUM_SEPOLIA \ --sig "run(address,uint256)" -- \ 0x346e11C1a869b88A8033e40B18Efdc4eCD9FFd02 43113 ``` Expected output: ```bash == Logs == Rate Limiter States for Chain Selector: 14767482510784806043 Pool Address: 0x346e11C1a869b88A8033e40B18Efdc4eCD9FFd02 Outbound Rate Limiter: Tokens: 0 Last Updated: 1747303443 Enabled: false Capacity: 0 Rate: 0 Inbound Rate Limiter: Tokens: 0 Last Updated: 1747303443 Enabled: false Capacity: 0 Rate: 0 ``` In these examples: - The rate limiter settings are currently disabled for both outbound and inbound transfers - The capacities and rates are set to 0. This means there are currently no restrictions on token transfers. In the next section, you will learn how to enable and configure these rate limiters to control token flow between chains. ### Update rate limiter settings Use the `UpdateRateLimiters` script to update the rate limiter configurations for an existing chain connection in your token pool. This script interacts with the [`setChainRateLimiterConfig`](/ccip/api-reference/evm/v1.6.1/token-pool#setchainratelimiterconfig) function of the `TokenPool` contract, allowing you to adjust the rate limits without altering other configurations like remote pool addresses. The `UpdateRateLimiters` task allows you to: - Enable or disable rate limiting for outbound or inbound transfers or both. - Set the capacity and rate for the rate limiters, controlling the flow of tokens. - Target a specific remote chain, updating rate limits for that chain only. Below is an explanation of the parameters used during the rate limiter update process: | Parameter | Description | Required | | --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ | -------- | | `poolAddress` | The address of the token pool being configured. | Yes | | `remoteChainId` | The ID of the remote blockchain to which this pool is linked. | Yes | | `rateLimiterToUpdate` | Specifies which rate limiters to update: `0` for outbound, `1` for inbound, or `2` for both. | Yes | | `outboundRateLimitEnabled` | A flag indicating whether to enable outbound rate limits for cross-chain transfers (`true` or `false`). | Yes | | `outboundRateLimitCapacity` | The maximum number of tokens allowed in the bucket for outbound transfers (in wei). **Note:** Applicable if outbound rate limits are enabled. | Yes | | `outboundRateLimitRate` | The number of tokens per second that the bucket is refilled for outbound transfers (in wei). **Note:** Applicable if outbound rate limits are enabled. | Yes | | `inboundRateLimitEnabled` | A flag indicating whether to enable inbound rate limits for cross-chain transfers (`true` or `false`). | Yes | | `inboundRateLimitCapacity` | The maximum number of tokens allowed in the bucket for inbound transfers (in wei). **Note:** Applicable if inbound rate limits are enabled. | Yes | | `inboundRateLimitRate` | The number of tokens per second that the bucket is refilled for inbound transfers (in wei). **Note:** Applicable if inbound rate limits are enabled. | Yes | | `network` | The blockchain network where the local token pool is deployed. Examples include `avalancheFuji`, `arbitrumSepolia`, `baseSepolia`, and `sepolia`. | Yes | **Command syntax**: ```bash forge script ./script/UpdateRateLimiters.s.sol:UpdateRateLimiters \ --rpc-url \ -vvv --broadcast \ --sig "run(address,uint256,uint8,bool,uint128,uint128,bool,uint128,uint128)" -- \ \ \ \ \ \ \ \ \ ``` **Notes**: - Updating only the **outbound** rate limiter: Set the `inboundRateLimitEnabled` value to `false` and the `inboundRateLimitCapacity` and `inboundRateLimitRate` values will be ignored when running the script. - Updating only the **inbound** rate limiter: Set the `outboundRateLimitEnabled` value to `false` and the `outboundRateLimitCapacity` and `outboundRateLimitRate` values will be ignored when running the script. **Example command**: Suppose you want to enable inbound and outbound rate limits for your token pool on Avalanche Fuji to control the number of tokens received or sent from/to Arbitrum Sepolia. We will use an existing token pool that interacts with an ERC20 token with 18 decimals: - **Token Pool on Avalanche Fuji**: | Property | Outbound Rate Limiter | Inbound Rate Limiter | | ---------------- | ----------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | | **Enabled** | `true` | `true` | | **Capacity** | `10000000000000000000` wei (equivalent to 10 tokens, based on 18 decimals) | `20000000000000000000` wei (equivalent to 20 tokens, based on 18 decimals) | | **Rate** | `100000000000000000` wei (equivalent to 0.1 token per second, based on 18 decimals) | `100000000000000000` wei (equivalent to 0.1 tokens per second, based on 18 decimals) | | *Replenish Time* | 100 seconds
`Capacity / Rate = 10 / 0.1 = 100` seconds | 200 seconds
`Capacity / Rate = 20 / 0.1 = 200` seconds | - **Token Pool on Arbitrum Sepolia**: Rate limits are the same as the Avalanche Fuji pool, but the inbound and outbound settings are swapped. | Property | Outbound Rate Limiter | Inbound Rate Limiter | | ---------------- | ----------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ | | **Enabled** | `true` | `true` | | **Capacity** | `20000000000000000000` wei (equivalent to 20 tokens, based on 18 decimals) | `10000000000000000000` wei (equivalent to 10 tokens, based on 18 decimals) | | **Rate** | `100000000000000000` wei (equivalent to 0.1 token per second, based on 18 decimals) | `100000000000000000` wei (equivalent to 0.1 tokens per second, based on 18 decimals) | | *Replenish Time* | 200 seconds
`Capacity / Rate = 20 / 0.1 = 200` seconds | 100 seconds
`Capacity / Rate = 10 / 0.1 = 100` seconds | 1. **Update rate limiter settings for the token pool on Avalanche Fuji**: Replace `` with your token pool address. ```bash forge script ./script/UpdateRateLimiters.s.sol:UpdateRateLimiters \ --rpc-url $RPC_URL_FUJI \ -vvv --broadcast \ --sig "run(address,uint256,uint8,bool,uint128,uint128,bool,uint128,uint128)" -- \ \ 421614 \ 2 \ true \ 10000000000000000000 \ 100000000000000000 \ true \ 20000000000000000000 \ 100000000000000000 ``` 2. **Update rate limiter settings for the token pool on Arbitrum Sepolia**: Replace `` with your token pool address. ```bash forge script ./script/UpdateRateLimiters.s.sol:UpdateRateLimiters \ --rpc-url $RPC_URL_ARBITRUM_SEPOLIA \ -vvv --broadcast \ --sig "run(address,uint256,uint8,bool,uint128,uint128,bool,uint128,uint128)" -- \ \ 43113 \ 2 \ true \ 10000000000000000000 \ 100000000000000000 \ true \ 20000000000000000000 \ 100000000000000000 ``` ### Verify the new rate limiter settings After applying the new rate limiter settings, verify that they have been updated correctly. Use the `GetPoolConfig` script again: 1. **Verify the updated rate limiter settings for the token pool on Avalanche Fuji**: ```bash forge script ./script/GetCurrentRateLimits.s.sol:GetCurrentRateLimits \ --rpc-url $RPC_URL_FUJI \ --sig "run(address,uint256)" -- \ 0xeB841acbc25549D4deB6Ed9401f3CbB529F3DC3e 421614 ``` Expected output: ```bash == Logs == Rate Limiter States for Chain Selector: 3478487238524512106 Pool Address: 0xeB841acbc25549D4deB6Ed9401f3CbB529F3DC3e Outbound Rate Limiter: Tokens: 8300000000000000000 Last Updated: 1747303782 Enabled: true Capacity: 10000000000000000000 Rate: 100000000000000000 Inbound Rate Limiter: Tokens: 8300000000000000000 Last Updated: 1747303782 Enabled: true Capacity: 20000000000000000000 Rate: 100000000000000000 ``` 2. **Verify the updated rate limiter settings for the token pool on Arbitrum Sepolia**: ```bash forge script ./script/GetCurrentRateLimits.s.sol:GetCurrentRateLimits \ --rpc-url $RPC_URL_ARBITRUM_SEPOLIA \ --sig "run(address,uint256)" -- \ 0x346e11C1a869b88A8033e40B18Efdc4eCD9FFd02 43113 ``` Expected output: ```bash == Logs == Rate Limiter States for Chain Selector: 14767482510784806043 Pool Address: 0x346e11C1a869b88A8033e40B18Efdc4eCD9FFd02 Outbound Rate Limiter: Tokens: 9800000000000000000 Last Updated: 1747303834 Enabled: true Capacity: 10000000000000000000 Rate: 100000000000000000 Inbound Rate Limiter: Tokens: 9800000000000000000 Last Updated: 1747303834 Enabled: true Capacity: 20000000000000000000 Rate: 100000000000000000 ``` ### Test the rate limiter settings To verify the rate limiter settings, initiate a cross-chain transfer between the token pools on Avalanche Fuji and Arbitrum Sepolia. The rate limiter configuration will control the flow of tokens between these pools. **Note**: Ensure that your externally owned account (EOA) has a sufficient balance of ERC20 tokens on Avalanche Fuji to complete the transfer. In the example below, we use a token pool at address `0xeB841acbc25549D4deB6Ed9401f3CbB529F3DC3e` on Avalanche Fuji, which has burn and mint privileges for the token at address `0x56e4CFf5009908D8d8C5Aac5479574f9aC66e145`. We will transfer this token from Avalanche Fuji to Arbitrum Sepolia. For your own test, substitute these addresses with the token pool and token addresses that you have deployed. 1. In your `script/output/` directory, make sure the `deployedToken_avalancheFuji.json` and `deployedTokenPool_avalancheFuji.json` files contain the correct token and token pool addresses. 2. **Test Capacity**: Because the outbound capacity set is `10000000000000000000` , let's transfer `10000000000000000001` tokens from Avalanche Fuji to Arbitrum Sepolia. This transfer should fail because the capacity is less than the number of tokens being transferred. - In your `script/` directory, open your `config.json` file, and set `tokenAmountToTransfer` to `10000000000000000001`. - Run the following command: ```bash forge script script/TransferTokens.s.sol --rpc-url $RPC_URL_FUJI --private-key $PRIVATE_KEY --broadcast ``` Expected output: ```bash == Logs == Estimated fees: 22167517387804854 Error: script failed: TokenMaxCapacityExceeded(10000000000000000000 [1e19], 10000000000000000001 [1e19], 0x56e4CFf5009908D8d8C5Aac5479574f9aC66e145) ``` Notice in the logs that the transfer failed because the capacity was exceeded: `TokenMaxCapacityExceeded`. 3. **Test Rate**: Now, let's transfer `10000000000000000000` tokens from Avalanche Fuji to Arbitrum Sepolia, which will empty the bucket. After this transfer, we will attempt to transfer another `10000000000000000000` tokens. This transfer will fail because it takes 100 seconds to replenish the bucket. 1. In your `script/` directory, open your `config.json` file, and set `tokenAmountToTransfer` to `10000000000000000000`. 2. **First transfer** (Successful): Command: ```bash forge script script/TransferTokens.s.sol --rpc-url $RPC_URL_FUJI --private-key $PRIVATE_KEY --broadcast ``` Expected output: ```bash == Logs == Estimated fees: 22167517387804854 Message ID: 0xb58325b6fd67f7d7197a9a1788dfe3593038b46c31c27753df6099c06ee0e7fa Check status of the message at https://ccip.chain.link/msg/b58325b6fd67f7d7197a9a1788dfe3593038b46c31c27753df6099c06ee0e7fa ``` 3. **Second transfer** (Failed): Command: ```bash forge script script/TransferTokens.s.sol --rpc-url $RPC_URL_FUJI --private-key $PRIVATE_KEY --broadcast ``` Expected output: ```bash == Logs == Estimated fees: 22167517387804854 Error: script failed: TokenRateLimitReached(38, 6200000000000000000 [6.2e18], 0x56e4CFf5009908D8d8C5Aac5479574f9aC66e145) ``` Notice in the logs that the transfer failed because the rate limit was exceeded: `TokenRateLimitReached`. > **CAUTION: Educational Example Disclaimer** > > This page includes an educational example to use a Chainlink system, product, or service and is provided to > demonstrate how to interact with Chainlink's systems, products, and services to integrate them into your own. This > template is provided "AS IS" and "AS AVAILABLE" without warranties of any kind, it has not been audited, and it may be > missing key checks or error handling to make the usage of the system, product or service more clear. Do not use the > code in this example in a production environment without completing your own audits and application of best practices. > Neither Chainlink Labs, the Chainlink Foundation, nor Chainlink node operators are responsible for unintended outputs > that are generated due to errors in code.