A package for talking to EVM blockchains (Ethereum and friends) from Elm.

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I’ve published quietgarden/elm-web3, a package for talking to EVM blockchains (Ethereum and friends) from Elm.

The core idea: wallet connection, transaction lifecycle, and contract calls are all modelled as explicit state machines. The
Wallet.State and Transaction.Status types make invalid states unrepresentable, so the compiler enforces that your UI handles
every case — no silent failures, no blank screens from an unhandled null.

What’s included:

  • Opaque validated types (Address, TxHash, ChainId, BigInt) — you can’t accidentally pass a TxHash where an Address
    is expected
  • Wallet state machine with EIP-6963 multi-wallet discovery
  • Transaction lifecycle from AwaitingSignature through Confirmed with revert reason decoding
  • Typed contract reads/writes, gas estimation, multicall batching, EIP-712 signing
  • ABI code generator from Foundry/Hardhat JSON

Dependencies: only elm/core, elm/json, elm/http, elm/time. The JS port bridge (~500 lines) has zero npm dependencies
— no ethers, no viem, just window.ethereum.

I’ve also included Lean 4 proofs for core type invariants (soundness, injectivity, roundtrip) and TLA+ model-checked specs for
the state machines. Some of the harder arithmetic proofs are stated with sketches rather than fully closed — honest about that.

elm install quietgarden/elm-web3

Feedback welcome, especially from anyone who’s worked with cmditch/elm-ethereum.

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