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Testnet proof

Three shielded transactions the browser wallet built, proved and broadcast on Zcash testnet, and a script to check them yourself.

The browser wallet built, proved and broadcast these Ironwood spends on Zcash testnet (NU7 is active there). Each one was read back from the same light server the wallet syncs from.

Zcash testnet · GetTransactionThree sends from the browser wallet
ceb45a85df00f55d8a7b6c4318c65aa22c33c702a4bff476c2feef0dee7d4e5d
block 4,529,708
c1569f9f34a75c6896b272f7804ed501285acbfb472ce1dcf53fc869fa6938e2
block 4,529,789
8a14a08bc1af88c6b8f644fdc22d11731e431a8b2257fccac4a3768430981b86
block 4,529,846
Read back on 2026-10-23 from zcash-testnet.chainsafe.dev: each transaction is 9,166 bytes. The first proved the browser wallet end to end; the other two were sent from the app, one directly and one over Oblivious HTTP.

Public testnet explorers follow an older testnet chain, so they don't show these. The light server does.

Check them yourself

GetTransaction takes the transaction id with its bytes reversed. This asks the light server for each one and prints the block height and the size; it needs only Python.

check_txids.py
import struct, urllib.request

URL = "https://zcash-testnet.chainsafe.dev/cash.z.wallet.sdk.rpc.CompactTxStreamer/GetTransaction"
TXIDS = [
    "ceb45a85df00f55d8a7b6c4318c65aa22c33c702a4bff476c2feef0dee7d4e5d",
    "c1569f9f34a75c6896b272f7804ed501285acbfb472ce1dcf53fc869fa6938e2",
    "8a14a08bc1af88c6b8f644fdc22d11731e431a8b2257fccac4a3768430981b86",
]

def varint(buf, i):
    value = shift = 0
    while True:
        byte = buf[i]; i += 1
        value |= (byte & 0x7F) << shift; shift += 7
        if byte < 0x80:
            return value, i

for txid in TXIDS:
    filt = bytes([0x1A, 32]) + bytes.fromhex(txid)[::-1]  # TxFilter.hash, reversed
    frame = b"\x00" + struct.pack(">I", len(filt)) + filt  # one gRPC-web frame
    req = urllib.request.Request(URL, data=frame, method="POST", headers={
        "content-type": "application/grpc-web+proto", "x-grpc-web": "1"})
    body = urllib.request.urlopen(req, timeout=30).read()
    msg = body[5:5 + struct.unpack(">I", body[1:5])[0]]  # RawTransaction
    i = size = height = 0
    while i < len(msg):
        tag = msg[i]; i += 1
        if tag >> 3 == 1:  # data
            size, i = varint(msg, i); i += size
        else:              # height
            height, i = varint(msg, i)
    print(txid[:16], "block", height, size, "bytes")

Timings measured on testnet

StepTimeSource
Orchard proving key warm-up11.8 sREADME evidence table, 2026-10-23
One proof, single-threadedabout 17.5 sREADME evidence table
Testnet block spacingabout 22–25 spackages/engine/src/constants.ts

ZIPs in use

The Zcash Improvement Proposals Umbra Trade follows, and the exact place in the code where each one applies.

On this page

Check them yourselfTimings measured on testnet