Ethereum: calling an API endpoint at a price of 0x and getting a 400 Bad Request error

The Error: 400 Bad Request

If your server does not return an error message when making the POST request, but returns a response with a 200 OK status code or another non-200 status code. This can happen for several reasons:

• The API endpoint is not configured correctly.

• The API has reached its usage limit (although this is unlikely to be the case).

• The server is throwing an internal error.

Addressing the error: Implementing a try-catch block

To handle these errors, we will use a try-catch block in our front-end code. Here is how you can modify your code:

const ethereumPrice = async () => {
const API_URL = '
const address = '0xYourEthereumAddress'; // Replace with your Ethereum address
try {
const response = await fetch(API_URL, {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({ amount: 1 }), // Replace with the input value
});
if (response.ok) {
const data = await response.json();
console.log(data);
} else {
throw new Error(Error ${response.status}: ${response.statusText});
}
} catch (error) {
console.error(error.message); // Log the error message
// You can also display an error message to the user
alert('Failed to fetch price. Please try again later.');
}
};

What’s going on here?

In this code:

• If the response is OK (200-299), we log the data returned by the API and continue execution.

• If the response indicates an error (400-499), we throw a new error object with the status code and message.

Conclusion

By using try-catch blocks to catch errors when making calls to the 0x Price API, you can ensure that your front-end code doesn’t crash if an error occurs. This approach provides a clean and maintainable way to handle errors in your application.