How to integrate Ethereum blockchain in Bubble

The direct way to integrate the Ethereum blockchain into Bubble is to use the API Connector and connect to a real Ethereum API service such as Infura, Alchemy, or QuickNode. Bubble cannot run Web3.js, MetaMask, or smart‑contract calls natively, so you must use an external blockchain node provider that exposes Ethereum JSON‑RPC over HTTPS.

How Bubble Actually Connects to Ethereum

Bubble apps cannot sign transactions or read the blockchain directly in the browser. Instead, you send requests to a provider like Infura, which gives you an HTTPS endpoint. That endpoint accepts standard Ethereum JSON‑RPC commands such as reading a wallet balance, reading a smart contract, or sending raw transactions.

• You use Bubble’s API Connector to create calls.
• You use your backend workflows if you want secure server‑side calls.
• You sign any transaction outside Bubble, because Bubble cannot securely hold private keys.

Step‑by‑Step Setup

First, create an Infura (or Alchemy) project and copy the HTTPS endpoint. Then, in Bubble, open the API Connector and create a POST call. Here is a working example for getting an address balance:

{
  "jsonrpc": "2.0",
  "method": "eth_getBalance",
  "params": ["0xYourWalletAddressHere", "latest"],
  "id": 1
}

Configure it as:

• Method: POST
• URL: your Infura/Alchemy HTTPS endpoint
• Body type: JSON
• Headers: Content-Type: application/json

The response will include the balance in Wei (a large number). You can convert it to ETH inside Bubble using expressions.

Calling Smart Contracts

You can call read-only smart contract functions with eth\_call. These require knowing the contract address and ABI-encoded function data. Encoding must be done outside Bubble (small backend service or prebuilt tool), because Bubble cannot generate ABI encoding on its own. Once you have the encoded data, you send it through API Connector the same way.

Sending Transactions

Bubble cannot sign Ethereum transactions, so you must sign the transaction client-side with MetaMask or server-side using your own backend. Bubble then sends the raw signed transaction using eth\_sendRawTransaction through the API Connector.

{
  "jsonrpc": "2.0",
  "method": "eth_sendRawTransaction",
  "params": ["0xSignedTxData"],
  "id": 1
}

This is the cleanest, safest way to integrate Ethereum into Bubble today.