janzeer-sdk (Python)

Official Python SDK for the Janzeer blockchain — a stake-free, permissionless Layer-1 with instant finality. Wallet keys and signing, transaction builders, a REST client, JSON-RPC over HTTP and WebSocket subscriptions, blocking and asyncio. Non-custodial by construction: keys never leave your process, the node only verifies.

pip install janzeer-sdk            # add [ws] for WebSocket subscriptions: pip install "janzeer-sdk[ws]"

Releases are published to PyPI from this repository's GitHub releases (trusted publishing, no stored token). To install the development head instead:

pip install "janzeer-sdk[ws] @ git+https://github.com/janzeerorg/janzeer-sdk-python"

60-second quickstart

from janzeer import Account, JanzeerClient, JanzeerRpc, TxBuilder, format_jnz, wait_for_finality

client = JanzeerClient("https://onion.janzeer.org")        # REST  (/api/v1)
rpc    = JanzeerRpc("https://onion.janzeer.org")           # JSON-RPC (/rpc)
me     = Account.from_mnemonic("abandon abandon … about")  # 12/24-word BIP39 phrase

print(me.checksum_address, format_jnz(client.balance(me.address)))

tx = me.sign_tx(TxBuilder.transfer(
    sender=me.address, to="0x598b1301acef3baba6ce25e38dd17b723f7b98b1",
    amount="1.25", data="hello", nonce=client.nonce(me.address),
))
client.submit(tx)                                          # HTTP 201, or a typed error
final = wait_for_finality(rpc, tx.hash)                    # one or two 15-second slots
print("final in block", final["blockHeight"])

That is the whole integration: derive → nonce → build → sign → submit → wait. A committed block is final (2f+1 BFT commit), so there is no confirmation count.

The same with asyncio: AsyncJanzeerClient, AsyncJanzeerRpc, JanzeerRpcWs and await_finality have the same methods and return awaitables.

What is in the box

Money is never a float

Amounts are decimal strings ("1.25"), int (whole coins) or decimal.Decimal. A float is refused with a TypeError everywhere — in the builders, in the amount helpers and in request bodies — because 0.1 is not representable in binary and a payment must not depend on how a float prints. Responses are parsed losslessly: numbers with a fraction arrive as Decimal, client.balance() returns a decimal string.

Results are plain JSON

Network calls return the node's JSON as dict / list values with the field names the node uses (blockHeight, senderAddress, …), documented in the API reference. Keys, transactions and errors are typed classes; the package ships py.typed.

Requirements

• Python 3.10 – 3.13 on Linux, macOS or Windows.
• coincurve (libsecp256k1), pycryptodome (keccak-256, AES-GCM), httpx; websockets for subscriptions. Wheels exist for all three systems: no compiler is needed.

Compatibility

SPEC_VERSION exports these values; the e2e test checks them against the node on the first call.

Examples

Runnable scripts in examples/: a transfer to finality, an address-activity subscription, the token life cycle, a validator registration, and a vault round trip. They read the JANZEER_* environment variables described in CONTRIBUTING.

Conformance

This SDK reproduces, byte for byte, the public test vectors every Janzeer SDK is tested against (key derivation, addresses, every transaction preimage, hash and signature, the vault fixture) and passes the shared 14-step end-to-end flow: https://github.com/janzeerorg/janzeer-sdk-conformance. See docs/conformance.md.

Other SDKs

TypeScript · Dart / Flutter · Kotlin / JVM / Android · Go

Licence

Apache License 2.0 — see LICENSE. Security reports: see SECURITY.