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MultiBaas manages contracts in two layers:
  • Library — contract definitions (ABI and bytecode)
  • On-chain — deployed instances linked to a blockchain address

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Adding a Contract to the Library

You can add a contract to the library in four ways:
  1. Direct ABI upload — paste an ABI JSON directly
  2. Solidity source upload — MultiBaas compiles it for you
  3. Address lookup — MultiBaas fetches the ABI from Blockscout or Etherscan by contract address
  4. Framework plugin — automated via the Hardhat or Forge plugin during deployment (see below)

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Deploying or Linking a Contract

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Deploy a new contract

  1. Go to Contracts → On-chain → + → Deploy Contract
  2. Select a contract from the library
  3. Fill in constructor parameters
  4. Optionally enable Sync Events and set a starting block for event indexing
  5. Submit — if using a Cloud Wallet, MultiBaas signs and submits the transaction automatically
  1. Go to Contracts → On-chain → + → Link Contract
  2. Enter the contract address (MultiBaas can auto-fetch the ABI from a block explorer)
  3. Select the contract definition from the library
  4. Optionally enable Sync Events

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Calling Contract Methods

Once a contract is linked, MultiBaas exposes all its functions via the REST API. Toggle on Developer Mode in the contract functions UI to see sample payload, curl, TypeScript, or golang code. The base URL for all API calls is: 
https://<deployment-id>.multibaas.com/api/v0
The API path uses /chains/ethereum/ as a fixed prefix regardless of the actual EVM network. This is a MultiBaas convention — it works correctly for Celo.

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Using the TypeScript SDK

Install the TypeScript SDK: 
npm install @curvegrid/multibaas-sdk
Configure the client: 
import * as MultiBaas from '@curvegrid/multibaas-sdk';

const config = new MultiBaas.Configuration({
  basePath: `${process.env.MULTIBAAS_DEPLOYMENT_URL}/api/v0`,
  accessToken: process.env.MULTIBAAS_API_KEY,
});

const contractsApi = new MultiBaas.ContractsApi(config);
Read a contract function: 
const response = await contractsApi.callContractFunction(
  'my-contract-alias',  // address alias configured in MultiBaas
  'MyContract',         // contract label in the library
  'balanceOf',          // method name
  {
    args: ['0xRecipientAddress'],
    signAndSubmit: false,
  },
);

console.log(response.data.result.output);
Write to a contract using a Cloud Wallet: 
const response = await contractsApi.callContractFunction(
  'my-contract-alias',
  'MyContract',
  'transfer',
  {
    args: ['0xRecipientAddress', '1000000000000000000'],
    from: process.env.CLOUD_WALLET_ADDRESS,
    signAndSubmit: true,
  },
);

console.log(response.data.result.tx.hash);
Setting signAndSubmit: true with a configured Cloud Wallet address instructs MultiBaas to sign and broadcast the transaction on your behalf. Write to a contract with an external wallet (viem): 
import { createWalletClient, custom } from 'viem';
import { celo } from 'viem/chains';

const walletClient = createWalletClient({
  chain: celo,
  transport: custom(window.ethereum),
});

// Get the unsigned transaction from MultiBaas
const response = await contractsApi.callContractFunction(
  'my-contract-alias',
  'MyContract',
  'transfer',
  {
    args: ['0xRecipientAddress', '1000000000000000000'],
    signAndSubmit: false,
  },
);

const tx = response.data.result.tx;

// Sign and submit with the user's connected wallet
await walletClient.sendTransaction({
  to: tx.to,
  data: tx.data,
  value: BigInt(tx.value ?? 0),
  account: userAddress,
});

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Framework Plugins

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Hardhat

The hardhat-multibaas-plugin automatically uploads and links contracts in your MultiBaas deployment as part of your Hardhat deploy scripts. 
npm install --save-dev hardhat hardhat-multibaas-plugin @nomicfoundation/hardhat-ignition
See the plugin repository for setup instructions.

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Foundry / Forge

The forge-multibaas plugin provides the same integration for Foundry-based projects. 
forge install curvegrid/forge-multibaas
See the plugin repository for setup instructions.