python-viem 0.1.1

Python library for viem chain metadata, enabling compatibility with Javascript tooling.

python-viem

python-viem is a lightweight utility for retrieving EVM chain metadata from a local snapshot (viem-chains.json). It supports fast O(1) lookups by either numeric chain ID or human-readable name.

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Installation

pip install python-viem

uv add python-viem # for uv users

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Features

• Instant chain metadata lookup by:
  • chain_id (e.g., 8453 → "Base")
  • name (e.g., "Polygon" → 137)
• Caches parsed data for fast access.
• Robust fallback: supports both object and array-style JSON formats.

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Usage

from python_viem import get_chain_by_id, get_chain_by_name

print(get_chain_by_id(8453)["name"])        # "Base"
print(get_chain_by_name("polygon")["id"])   # 137

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JSON Format

Your viem-chains.json can use either format:

Object-style (preferred):

{
  "mainnet": { "id": 1, "name": "Ethereum Mainnet", ... },
  "polygon": { "id": 137, "name": "Polygon", ... }
}

Array-style (also supported):

[
  { "id": 1, "name": "Ethereum Mainnet", ... },
  { "id": 137, "name": "Polygon", ... }
]

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Functions

get_chain_by_id(chain_id: int) -> Optional[Dict[str, Any]]

get_chain_by_name(name: str) -> Optional[Dict[str, Any]]

Both return the full chain metadata dictionary or None if not found.

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Project Structure

python_viem/
├── __init__.py
├── viem.py
├── viem-chains.json   ← bundled chain metadata

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License

MIT