Question 1

How do I send a transaction with Web3.swift?

Accepted Answer

First, get the nonce using web3.eth.getTransactionCount, create an EthereumTransaction object, sign it with a private key, and call web3.eth.sendRawTransaction. The README provides a step-by-step example with PromiseKit for async handling.

Question 2

Web3.swift or web3.js for an iOS app?

Accepted Answer

Web3.swift is better for native iOS/macOS apps as it's pure Swift, avoiding JavaScript bridge overhead and performance issues. However, web3.js has a larger ecosystem and is more suitable for web-based DApps or cross-platform projects using JavaScript.

Question 3

Can I use Web3.swift on Linux?

Accepted Answer

Yes, Web3.swift supports Linux on little-endian systems with Swift, Foundation, and Glibc. It's officially tested on Ubuntu 16.04 and 20.04, making it viable for server-side Swift projects interacting with Ethereum.

Question 4

How to parse a smart contract ABI from JSON?

Accepted Answer

Use the Web3ContractABI module to dynamically parse JSON ABI strings with web3.eth.Contract(json:abiKey:address:). However, be aware of known issues with fallback functions, which may require manual ABI editing.

Question 5

Does Web3.swift support ERC20 tokens?

Accepted Answer

Yes, it includes static contract interfaces like GenericERC20Contract for ERC20, allowing easy balance checks and transfers without manual ABI parsing, as shown in the README examples.

Question 6

Why am I getting 'Couldn't parse ABI Object' error?

Accepted Answer

This error typically occurs when the ABI includes a fallback function. You need to remove the fallback function fragment from the JSON ABI, as detailed in the common errors section of the README.

Web3.swift

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