Guides → dAPIs

Subscribing to Self-Funded dAPIs ​

With Self-Funded dAPIs, you can fund the dAPI with your own funds. The amount of gas you supply will determine how long your dAPI will be available for use. If you run out of gas, you can fund the dAPI again to keep it available for use. This is a good option if you are not planning to use the dAPI for a long period of time or if you are not planning to use the dAPI in a production environment.

API3 Market ​

The API3 Market➚ provides all the tooling to seamlessly access dAPI services. For self-funded data feeds this end-to-end process consists of:

1. Exploring and selecting your data feed
2. Funding a sponsor wallet
3. Deploying a proxy contract to access the data feed
3a. Deploying a proxy contract during funding
3b. Deploying a proxy contract from the API3 Market details page
3c. Verifying the deployed proxy contract

1. Exploring and selecting your data feed ​

The API3 Market➚ provides a list of all the dAPIs available across multiple chains including testnets. You can filter the list by chains and data providers. You can also search for a specific dAPI by name. Once selected you will land on the details page where you can find more information about the dAPI.

2. Funding a sponsor wallet ​

Once you have selected your dAPI, you can fund the dAPI by using the market UI to send funds to the sponsorWallet, make sure your:

• Wallet is connected to the market and is the same network as the dAPI you are funding
• Balance of the wallet should be greater than the amount you are sending to the sponsorWallet

To fund the dAPI, you need to click on the "Fund Gas" button.

This will bring up the API3 gas estimator UI that allows users to understand how much gas is needed for the dAPI to provide on-chain values for the selected time.

Clicking ''Send'' will initiate a transaction sending the amount entered into the gas estimator from a users wallet to the sponsor wallet of the respective data feed. 15 minutes later the feed will activate.

Always verify that you are signing a transaction with the expected amount, networks, and destination address. Each dAPI has a unique funding address.

Once the transaction is broadcasted & confirmed on the blockchain a transaction confirmation screen will appear.

3. Deploying a proxy contract to access the data feed ​

Smart contracts can interact and read values from contracts that are already deployed on the blockchain. By deploying a proxy contract via the API3 market, a dAPP can interact and read values from a dAPI like ETH/USD.

Once the dAPI is funded, you can deploy a proxy contract to access the data feed. Proxy contracts can be deployed in two ways:

• During the funding process
• Deploying from the API3 Market details page of the dAPI

3a. Deploying a proxy contract during funding ​

If you are deploying a proxy contract during the funding process, you will see the following UI.

Clicking on the "Get proxy" button will initiate a transaction to your metamask that will deploy a proxy contract.

Once the transaction is broadcasted & confirmed on the blockchain, the proxy contract address will be shown on the UI.

3b. Deploying a proxy contract from the API3 Market details page ​

If you are deploying a proxy contract from the API3 Market details page, you will see the following UI.

Clicking on the "Get Proxy" button will initiate a transaction to your metamask that will deploy a proxy contract. Once the transaction is broadcasted & confirmed on the blockchain, the proxy contract address will be shown on the UI.

3c. Verifying the deployed proxy contract ​

Before using the proxy contract, you should verify if the proxy contract points to the correct dapiNameHash and api3ServerV1 address. This can be done by viewing the code of the proxy on the block explorer.

The api3ServerV1 address should be the same as the address of the Api3ServerV1 contract. Refer to the chains and contract addresses page for the address of the Api3ServerV1 contract on different chains.

The dapiNameHash should be the same as the dapiNameHash of the dAPI you are using which can be computed using the following cli commands:

$ npm install -g @ethersproject/cli

$ ethers eval 'utils.solidityKeccak256(["bytes32"],[utils.formatBytes32String("ETH/USD")])'

0x9e6138f8f57d7b493a8364edb0a0ac92399dfd890eecb9121050836a1749ba42 ← dapiNameHash

Where ETH/USD is the dapiName from the details page of the dAPI on the API3 Market.

Once you have verified the dapiNameHash and Api3ServerV1 address, you can start using the proxy contract to read the data feed.