# gleeth
[](https://hex.pm/packages/gleeth)
[](https://hexdocs.pm/gleeth/)
An Ethereum library for Gleam, targeting the Erlang (BEAM) runtime. Provides JSON-RPC client, transaction signing, ABI encoding/decoding, and wallet management.
> **Warning**: gleeth has not been audited and is in early development. It is
> recommended for testnet and development use only. Do not use with real funds
> in production without thorough independent review.
## Installation
```sh
gleam add gleeth
```
## Quick start
### Read chain state
```gleam
import gleeth/provider
import gleeth/rpc/methods
pub fn main() {
let assert Ok(p) = provider.new("http://localhost:8545")
// Get the latest block number
let assert Ok(block_number) = methods.get_block_number(p)
// Check an address balance
let assert Ok(balance) = methods.get_balance(
p,
"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
)
}
```
### Sign and send a transaction (builder API)
The builder API accepts human-readable values - no manual hex conversion needed.
```gleam
import gleeth/crypto/transaction
import gleeth/crypto/wallet
import gleeth/gas
import gleeth/provider
import gleeth/rpc/methods
pub fn main() {
let assert Ok(p) = provider.new("http://localhost:8545")
let assert Ok(w) = wallet.from_private_key_hex("0xac09...")
// Build and sign in a pipeline
let assert Ok(signed) =
transaction.build_legacy()
|> transaction.legacy_to("0x70997970C51812dc3A010C7d01b50e0d17dc79C8")
|> transaction.legacy_value_ether("1.5")
|> transaction.legacy_gas_limit_int(21_000)
|> transaction.legacy_gas_price_gwei("20.0")
|> transaction.legacy_nonce_int(0)
|> transaction.legacy_chain(1)
|> transaction.sign_legacy(w)
// Broadcast and wait for receipt
let assert Ok(tx_hash) = methods.send_raw_transaction(p, signed.raw_transaction)
let assert Ok(receipt) = methods.wait_for_receipt(p, tx_hash)
}
```
For lower-level control, use `create_legacy_transaction` with hex strings directly:
```gleam
pub fn main() {
let assert Ok(p) = provider.new("http://localhost:8545")
let assert Ok(w) = wallet.from_private_key_hex("0xac09...")
// Gas estimation in one call
let sender = wallet.get_address(w)
let assert Ok(est) = gas.estimate_legacy(p, sender, "0x7099...", "0xde0b6b3a7640000", "0x")
let assert Ok(nonce) = methods.get_transaction_count(p, sender, "pending")
let assert Ok(tx) = transaction.create_legacy_transaction(
"0x70997970C51812dc3A010C7d01b50e0d17dc79C8",
"0xde0b6b3a7640000", // 1 ETH in wei hex
est.gas_limit, // from estimation
est.gas_price, // from estimation
nonce, // from RPC
"0x", // no calldata
1, // mainnet
)
let assert Ok(signed) = transaction.sign_transaction(tx, w)
let assert Ok(tx_hash) = methods.send_raw_transaction(p, signed.raw_transaction)
}
```
### Call a contract
```gleam
import gleeth/provider
import gleeth/rpc/methods
pub fn main() {
let assert Ok(p) = provider.new("http://localhost:8545")
// Call balanceOf(address) on an ERC-20
let assert Ok(result) = methods.call_contract(
p,
"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48", // USDC
"0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
)
}
```
### ABI encoding
```gleam
import gleeth/ethereum/abi/encode
import gleeth/ethereum/abi/types.{Uint, Address, AbiUintValue, AbiAddressValue}
pub fn main() {
// Encode a function call: transfer(address, uint256)
let assert Ok(calldata) = encode.encode_call(
"transfer(address,uint256)",
[Uint(256), Address],
[
AbiAddressValue("0x70997970C51812dc3A010C7d01b50e0d17dc79C8"),
AbiUintValue(1000000),
],
)
}
```
## Features
- **Transaction builder** - pipeline API with human-readable values (`value_ether("1.5")`, `gas_price_gwei("20.0")`)
- **Transaction signing** - Legacy (Type 0) and EIP-1559 (Type 2) with EIP-155 replay protection
- **Transaction decoding** - decode raw transactions, recover sender address
- **Gas estimation** - `gas.estimate_legacy` and `gas.estimate_eip1559` in a single call
- **Receipt polling** - `wait_for_receipt` with exponential backoff
- **Nonce manager** - local nonce tracking for multi-transaction sequences
- **Wei conversions** - `wei.from_ether("1.5")`, `wei.to_gwei(hex)`, `wei.from_int(21000)`
- **JSON-RPC client** - block number, balance, call, code, estimate gas, storage, logs, transactions, receipts, fee history
- **Provider abstraction** - opaque type with URL validation and chain ID caching
- **ABI system** - full encoding/decoding for all Solidity types, calldata decoding, revert reason decoding, JSON ABI parsing, event log decoding
- **EIP-55 addresses** - `address.checksum` and `address.is_valid_checksum`
- **EIP-191 signing** - `sign_personal_message`, `recover_personal_message`, `verify_personal_message`
- **Wallet management** - key generation, message signing, signature recovery
- **Crypto primitives** - keccak256 (via ex_keccak NIF), secp256k1 (via ex_secp256k1 NIF)
- **RLP encoding/decoding** - per Ethereum Yellow Paper spec
## Requirements
- Gleam >= 1.14.0
- Erlang/OTP >= 27
- Elixir (for ex_keccak and ex_secp256k1 NIF compilation)
Run `mix local.hex --force` before first build if Elixir is freshly installed.
## Development
```sh
gleam build # Compile
gleam test # Run all tests
gleam format # Format code
gleam docs build # Generate documentation
```
Further documentation can be found at <https://hexdocs.pm/gleeth>.
