A minimal example showing how to build an Ethereum smart contract HTTP API with Node.js, Express and Infura.
Relevant files
- Main server: /server.js
- Runtime config: /config.json
- Project metadata: /package.json
- License: /LICENSE
- Git ignore: /.gitignore
Prerequisites
- Node.js (recommended LTS)
- An Ethereum provider URL (e.g. Infura project endpoint)
- A wallet private key set in the environment
Security notice
- Do NOT commit or store private keys in the repo. The server reads the private key from the environment variable
walletPrivateKey(seewalletPrivateKey). - Use a dedicated wallet with limited funds for testing.
- Ensure your provider URL and keys are stored securely.
Quick setup
git clone [email protected]:compound-developers/api-guide-example.git
cd api-guide-example
npm installnode server.js
These are the possible calls that can be made with cURL.
curl localhost:3000/wallet-balance/eth/
curl localhost:3000/wallet-balance/ceth/
curl localhost:3000/supply/eth/9000
curl localhost:3000/protocol-balance/eth/
curl localhost:3000/redeem/eth/123Here is an example of outputs for a series of API calls. The wallet started out with 100 ETH.
curl localhost:3000/wallet-balance/eth/
> 100
curl localhost:3000/wallet-balance/ceth/
> 0
curl localhost:3000/supply/eth/5
> OK
curl localhost:3000/protocol-balance/eth/
> 4.999999999885010676
curl localhost:3000/wallet-balance/eth/
> 94.99788632
curl localhost:3000/wallet-balance/ceth/
> 249.85542658
curl localhost:3000/redeem/eth/249.85542658
> OK
curl localhost:3000/protocol-balance/eth/
> 0
curl localhost:3000/wallet-balance/ceth/
> 0
curl localhost:3000/wallet-balance/eth/
> 99.995909700269046879