Python Substrate Interface

Description

This library specializes in interfacing with a Substrate node; querying storage, composing extrinsics, SCALE encoding/decoding and providing additional convenience methods to deal with the features and metadata of the Substrate runtime.

Documentation

Installation

pip install substrate-interface

Initialization

Using embedded light client

substrate = SubstrateInterface(chainspec="polkadot_asset_hub", relay_chainspecs=["polkadot"])

Using node RPC endpoint

substrate = SubstrateInterface(url="ws://127.0.0.1:9944")

After connecting certain properties like ss58_format will be determined automatically by querying the RPC node. At the moment this will work for most MetadataV14 and above runtimes like Polkadot, Kusama, Acala, Moonbeam. For older or runtimes under development the ss58_format (default 42) and other properties should be set manually.

Quick usage

Balance information of an account

result = substrate.query('System', 'Account', ['F4xQKRUagnSGjFqafyhajLs94e7Vvzvr8ebwYJceKpr8R7T'])
print(result.value['data']['free']) # 635278638077956496

Create balance transfer extrinsic

call = substrate.compose_call(
    call_module='Balances',
    call_function='transfer',
    call_params={
        'dest': '5E9oDs9PjpsBbxXxRE9uMaZZhnBAV38n2ouLB28oecBDdeQo',
        'value': 1 * 10**12
    }
)

keypair = Keypair.create_from_uri('//Alice')
extrinsic = substrate.create_signed_extrinsic(call=call, keypair=keypair)

receipt = substrate.submit_extrinsic(extrinsic, wait_for_inclusion=True)

print(f"Extrinsic '{receipt.extrinsic_hash}' sent and included in block '{receipt.block_hash}'")

Contact and Support

For questions, please see the Substrate StackExchange or Github Discussions.

License

https://github.com/JAMdotTech/py-polkadot-sdk/blob/master/LICENSE

Metadata

Release files for substrate-interface 1.8.1

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for substrate-interface 1.8.1
File	Size	Uploaded
substrate_interface-1.8.1.tar.gz	1.5 MB	Jan 20, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for substrate-interface 1.8.1
File	Interpreter	ABI	Platform	Reset
substrate_interface-1.8.1-py3-none-any.whl 1.5 MB Jan 20, 2026	Python 3	none	any	Details

Total release size: 2.9 MB

Release files / substrate_interface-1.8.1.tar.gz

Download URL	substrate_interface-1.8.1.tar.gz
Size	1.5 MB
Tags	Source
SHA-256 checksum How to use checksums	`821be590fa4f3d9bc731b4c370341b57cd98ef3419c81289cd369bdeefc008de`
BLAKE2b-256 checksum How to use checksums	`c53fe1483635a892b84727187cf8ba8477a20e4036361202650a0bdb93eacf8b`
Upload date	Jan 20, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.12.12`

Release files / substrate_interface-1.8.1-py3-none-any.whl

Download URL	substrate_interface-1.8.1-py3-none-any.whl
Size	1.5 MB
Tags	Python 3
SHA-256 checksum How to use checksums	`07737b0dc86fb8962ec09c3518577556534f9ffa58ef1164fc70ffe8a5c54837`
BLAKE2b-256 checksum How to use checksums	`c72ed6e2bb34473bfc8b6e915a21ee1a5dbf67c57dff8abea407e4e46cee5d83`
Upload date	Jan 20, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.12.12`