skillfed

clvm

[Contract Language | Chialisp] Virtual Machine

clvm v0.9.15 124.8K downloads/30d#11,852 on PyPI89
Permissive license https://opensource.org/licenses/Apache-2.0 Active released

What it is and what it does

clvm is a virtual machine implementation for Chialisp, a LISP-like smart contract language designed for the Chia blockchain. It interprets and executes Chialisp programs that define conditions for spending cryptocurrency—essentially a runtime for writing contracts that encumber and release funds based on cryptographic proofs and other conditions.

The package is in active development (Alpha status) and maintained by the Chia Network team. It depends on chia_rs for performance-critical operations and uses standard library compatibility shims (importlib_metadata, typing-extensions) for broad Python version support. It's positioned as a developer tool for blockchain engineers building on Chia, not a general-purpose language runtime.

Use it for:

  • Building Chia blockchain smart contracts that define spending conditions and fund release logic
  • Testing Chialisp programs locally before deployment to a live blockchain network
  • Integrating Chia contract execution into Python-based wallet or node software
  • Prototyping cryptocurrency payment schemes and escrow logic using Chialisp syntax

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

A LISP-like virtual machine for writing and executing smart contracts that control fund encumbrance and release on blockchain networks.

Yes, if you are developing on the Chia blockchain or need to execute Chialisp contracts in Python. The package is actively maintained, has no known vulnerabilities, and installs cleanly. However, it is in Alpha status, so expect API changes and verify production readiness for your use case before committing to it in critical systems.

Install

clvm on PyPI

pip

pip install clvm

uv

uv add clvm

poetry

poetry add clvm

Installing clvm

Before you install

Low install friction with a pure-Python wheel distribution. The package is actively maintained with recent commits and supports current Python versions (3.8 through 3.11). Three runtime dependencies keep the dependency tree manageable.

License in practice

Apache 2.0 permissive license allows commercial and private use with minimal restrictions, making it suitable for production deployment in proprietary systems.

Quickstart

pip install clvm

import clvm
# Use the virtual machine to execute Chialisp contracts
# See https://chialisp.com/ for language documentation

Requires Python 3.8.1 or later; depends on chia_rs which may require a Rust toolchain for compilation on some platforms.

Verify before relying

  • Whether chia_rs requires compilation from source on all platforms or if pre-built wheels are available
  • Performance characteristics and typical execution speed for contract evaluation
  • Maturity level beyond 'Alpha' status and production readiness guarantees

Package facts

License https://opensource.org/licenses/Apache-2.0 (permissive)
Python support supports the current Python release (<4,>=3.8.1)
Install friction low — pure-Python wheel
Runtime dependencies 3 — chia_rs, importlib_metadata, typing-extensions
Maintenance actively maintained — 331 days since the last release
Last repo commit
First released
Downloads 124,789/month — #11,852 on PyPI (30-day window, as of 2026-08-14)
Known vulnerabilities none known (OSV.dev, checked 2026-08-14)

Evidence: clvm-0.9.15-py3-none-any.whl

Development Status :: 3 - AlphaLicense :: OSI Approved :: Apache Software LicenseProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Topic :: Security :: Cryptography

Tags

lisp virtual machinesmart contract languageblockchain scriptingchialisp interpreterfund encumbrancecontract execution enginecryptocurrency smart contracts
blockchainsmart-contractschia-network

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Further reading