---
id: eth-tester
version: "0.13.0b1"
license: MIT
license_treatment: permissive
maintenance: aging
---

# eth-tester — eth-tester: Tools for testing Ethereum applications.

License: permissive · Maintenance: aging · Downloads: 287.3K/mo

## What it is and what it does

eth-tester is an in-memory Ethereum blockchain simulator that lets you test Ethereum applications and smart contracts locally without connecting to a live network. It provides a complete EthereumTester API for account management, transaction submission, block mining, and state queries—all running in Python with deterministic, reproducible behavior.

The library enforces strict input/output formats (hexadecimal strings for hashes and addresses, integers for numeric values) and includes features like auto-mining of transactions, time travel, and manual block mining. It depends on eth-abi, eth-account, eth-keys, eth-utils, rlp, and semantic_version to handle cryptographic operations and data encoding.

Use it for:

- Unit testing smart contracts during development before deployment to testnet or mainnet
- Integration testing Ethereum dApps that interact with multiple accounts and contract state
- Prototyping blockchain logic and validating transaction flows without external dependencies
- Educational projects and tutorials demonstrating Ethereum mechanics in a controlled environment
- Simulating account operations and balance queries in isolation

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

eth-tester provides an in-memory Ethereum blockchain simulator for testing smart contracts and Ethereum applications without needing a live network or node.

Yes, if you are testing Ethereum applications locally. eth-tester is the standard in-memory simulator for the Ethereum Python ecosystem and has low install friction. However, be aware that maintenance is aging (last release 2025-04-23, no recent commits visible) and the pre-alpha classifier suggests it may not be production-hardened; verify test coverage and reliability for your specific use case before relying on it for critical contract validation.

## Install

pip install eth-tester
uv add eth-tester
poetry add eth-tester

## Installing eth-tester

Before you install: Low install friction with a pure-Python wheel and six runtime dependencies. Maintenance status is aging—last release was 2025-04-23 and the repository shows no recent activity, though it remains unarchived and receives modest community attention (376 stars).

License in practice: MIT license permits free use, modification, and distribution with minimal restrictions, making it suitable for both open-source and commercial projects.

Quickstart:

pip install eth-tester

from eth_tester import EthereumTester

t = EthereumTester()
accounts = t.get_accounts()
balance = t.get_balance(accounts[0])
tx_hash = t.send_transaction({
    'from': accounts[0],
    'to': accounts[1],
    'value': 1,
    'gas': 30000
})

Verify before relying:

- Whether the pre-alpha status (Development Status :: 2) indicates active development or dormancy relative to the aging maintenance signal
- Current test coverage and reliability for production-grade contract testing workflows
- Support for specific transaction types and fee mechanisms beyond basic transaction submission

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 287.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

ethereum testing library, local blockchain simulator, ethereum smart contract testing, mock ethereum node, ethereum dapp testing, ethereum, blockchain-testing, smart-contracts

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