Deployment Guide

Prerequisites

• Foundry installed
• A funded deployer wallet
• An RPC endpoint for your target network
• An Etherscan API key for contract verification

Setup

git clone https://github.com/rxbryan/chainlink-price-feed-consumer
cd chainlink-price-feed-consumer
forge install

forge install reads foundry.toml and installs all library dependencies declared in [dependencies]. No separate npm install required.

Foundry configuration

[profile.default]
src     = "src"
out     = "out"
libs    = ["lib"]
test    = "test"
script  = "script"
solc_version   = "0.8.19"
optimizer      = true
optimizer_runs = 200
remappings = [
    "@chainlink/contracts/=lib/chainlink/contracts/",
    "@openzeppelin/contracts/=lib/openzeppelin-contracts/contracts/",
]

optimizer_runs = 200 is the standard setting for contracts that will be called frequently. Increase it if your consuming contract calls getPrice in a tight loop; decrease it if deployment cost is the primary concern.

Environment variables

Variable	Required	Default	Description
RPC_URL	Yes	n/a	RPC endpoint for target network
PRIVATE_KEY	Yes	n/a	Deployer private key
ETHERSCAN_API_KEY	Yes (for verification)	n/a	Block explorer API key
FEED_ADDRESS	No	Sepolia ETH/USD	Chainlink aggregator address
STALENESS_SECONDS	No	3600	Max acceptable round age
MAX_DEVIATION_BPS	No	500	Max deviation in basis points
UPTIME_FEED	L2 only	address(0)	Sequencer uptime feed address

L1 deployment (Sepolia)

1. Set environment variables:

   export RPC_URL=https://eth-sepolia.g.alchemy.com/v2/<your-key>
   export PRIVATE_KEY=<your-private-key>
   export ETHERSCAN_API_KEY=<your-api-key>

2. Optionally override feed parameters:

   export FEED_ADDRESS=0x694AA1769357215DE4FAC081bf1f309aDC325306  # Sepolia ETH/USD
   export STALENESS_SECONDS=3600
   export MAX_DEVIATION_BPS=500

3. Deploy and verify:

   forge script script/Deploy.s.sol \
     --rpc-url $RPC_URL \
     --private-key $PRIVATE_KEY \
     --broadcast \
     --verify \
     --etherscan-api-key $ETHERSCAN_API_KEY

L2 deployment (Arbitrum, Optimism, Base)

L2 deployments require the UPTIME_FEED variable. The deploy script sets the sequencer uptime feed address on the deployed contract automatically if this variable is present.

1. Set environment variables including the uptime feed:

   export RPC_URL=https://arb-mainnet.g.alchemy.com/v2/<your-key>
   export PRIVATE_KEY=<your-private-key>
   export ETHERSCAN_API_KEY=<your-api-key>
   export FEED_ADDRESS=0x639Fe6ab55C921f74e7fac1ee960C0B6293ba612  # Arbitrum ETH/USD
   export UPTIME_FEED=0xFdB631F5EE196F0ed6FAa767959853A9F217697D  # Arbitrum sequencer

2. Deploy:

   forge script script/Deploy.s.sol \
     --rpc-url $RPC_URL \
     --private-key $PRIVATE_KEY \
     --broadcast \
     --verify \
     --etherscan-api-key $ETHERSCAN_API_KEY

Caution

Do not deploy to an L2 without setting UPTIME_FEED. A deployment without the sequencer check is unsafe on any network that uses a sequencer.

Post-deployment

After deployment, call updateBaseline() if the constructor price is significantly different from the current market price. This is unlikely but can occur if the feed was stale at deployment time.

If using the deviation guard, establish a process for calling updateBaseline() when the asset price has moved legitimately and the contract needs to accept prices in the new range.

Feed addresses

• All networks: docs.chain.link/data-feeds/price-feeds/addresses
• Sequencer uptime feeds: docs.chain.link/data-feeds/l2-sequencer-feeds