---
id: smoldot-light
version: "0.1.0"
license: unclear
license_treatment: unclear
maintenance: aging
---

# smoldot-light — Python bindings for the smoldot_light Rust crate.

License: unclear · Maintenance: aging · Downloads: 143.5K/mo

## What it is and what it does

smoldot-light is a Python wrapper around the smoldot_light Rust crate, enabling you to run a lightweight Polkadot or Substrate blockchain client directly in Python. It provides a SmoldotClient class that loads chain specifications, manages blockchain state, and handles JSON-RPC requests and responses. The package is built using PyO3 and maturin, exposing Rust's efficient light-client logic to Python code without requiring a separate node process.

The typical workflow is to instantiate a SmoldotClient, load a chain spec (either from a file or fetched from a running node), add chains to the client, send JSON-RPC requests to query blockchain state, and drain responses asynchronously. It is designed to integrate with py-polkadot-sdk for higher-level Substrate interaction, though the package itself handles only the low-level client plumbing and does not depend on external Python runtime libraries.

Use it for:

- Run a lightweight Polkadot or Kusama client in a Python application without spawning a separate node process.
- Query blockchain state via JSON-RPC from Python by loading a chain spec and sending structured requests.
- Embed a Substrate light client in a bot, monitoring tool, or data-collection pipeline that needs direct blockchain access.
- Prototype or test Substrate chain interactions in Python without setting up a full node infrastructure.
- Connect parachain clients to relay chains by passing relay chain IDs when adding chains to the client.

## Worth the install?

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

Python bindings for the smoldot_light Rust crate that run a lightweight Polkadot client and expose JSON-RPC request/response plumbing for blockchain interaction.

Yes, if you need a lightweight Polkadot/Substrate client in Python and are comfortable with early-stage, minimally maintained code. The package has no known vulnerabilities and prebuilt wheels reduce friction. However, verify the license terms first, confirm Python version compatibility (wheels only for 3.10–3.11), and assess whether the 212-day gap since release signals active support or abandonment for your use case.

## Install

pip install smoldot-light
uv add smoldot-light
poetry add smoldot-light

## Installing smoldot-light

Before you install: Medium install friction due to compiled Rust bindings; prebuilt wheels available for Python 3.10–3.11 across Linux, macOS, and Windows architectures. Package is aging (212 days since release) with minimal maintenance signal and only 2 repository stars.

License in practice: License treatment is unclear—no SPDX identifier or raw license text is declared. Verify the actual license terms in the repository before adopting this package in a commercial or copyleft-sensitive context.

Quickstart:

from smoldot_light import SmoldotClient

client = SmoldotClient()
with open("polkadot.json", "r", encoding="utf-8") as f:
    chain_spec = f.read()
relay_chain_id = client.add_chain(chain_spec)
client.json_rpc_request(relay_chain_id, '{"id":1,"jsonrpc":"2.0","method":"system_name","params":[]}')
responses = client.drain_responses(relay_chain_id, max=10)

Requires Python >=3.8; prebuilt wheels are available only for Python 3.10 and 3.11, so other versions may require building from source.

Verify before relying:

- Whether the package is actively maintained or if the 212-day gap since last release indicates abandonment.
- What the actual license is, given that license_treatment is marked unclear.
- Whether this package is intended for production use or remains experimental/proof-of-concept.
- Compatibility with py-polkadot-sdk versions and whether that integration is documented.

## Package facts

- License: not declared (unclear)
- Python support: supports_current
- Install friction: medium
- Maintenance: aging
- Downloads: 143.5K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

polkadot light client python, substrate json-rpc client, blockchain light client bindings, polkadot python sdk, rust substrate client python, lightweight blockchain node, chain spec loader python, blockchain, substrate, rust-bindings

[View on SkillFed](https://skillfed.io/packages/smoldot-light) · [View on PyPI](https://pypi.org/project/smoldot-light/)