blaketest

A client-side taproot wallet for the Bitcoin BLAKE2b chain on testnet4. Keys never leave the browser. Spends sign with the unified opt-in sighash, so they cannot be replayed onto the SHA256d chain.

Live: https://bitcoin-blake.github.io/blaketest/

Testnet4 only. Coins have no value. Never paste a mainnet key into this wallet. If you want a mainnet wallet for the chain, use the Sparrow BLAKE2b build or Shrike.

What it does

• Generates or imports a key (hex, Nostr nsec, or WIF). The x-only public key is used directly as the taproot witness program, so the tb1p address and the Nostr npub are the same key.
• Shows balance and history, sends to tb1q, tb1p and P2WSH addresses, with RBF on.
• Signs every input with SIGHASH_ALL | SIGHASH_UNIFIED (0x21), the replay-protection sighash shipped in Bitcoin Knots v29.4.1.knots20260508 (PR #357). Testnet4 activated it at block 150,308.
• Talks to an Esplora-style API. Default is https://mempool.guide/testnet4/api.

Getting test coins

Your address is the same on both testnet4 chains. Request coins from a SHA256d testnet4 faucet such as faucet.activetk.jp, then use Check SHA256d testnet4 for coins to carry across on the wallet's home tab. Faucet payouts are signed with plain SIGHASH_ALL, so the same bytes are valid on the BLAKE2b chain; the wallet fetches the raw transaction from mempool.space and relays it to the BLAKE2b backend. It signs nothing. This only works while the faucet's coin lineage exists on both chains.

Pointing it at your own node

Append ?api=<base> once and it is remembered in localStorage:

https://bitcoin-blake.github.io/blaketest/?api=http://localhost:3006/api
https://bitcoin-blake.github.io/blaketest/?api=reset

The base must serve the Esplora endpoints the wallet uses: address/:a, address/:a/txs, address/:a/utxo, v1/fees/recommended, and POST tx. A mempool or electrs instance behind a Knots 29.4.1 testnet4 node does. Explorer links are the base with /api stripped.

Running your own backend

mempool.guide's testnet4 follows a dead release-candidate chain, so a real backend means your own Knots 29.4.1 testnet4 node. shim/server.mjs is a small Esplora-shaped HTTP server over a jasonsopko/electrs (blake2b branch) instance plus Knots RPC:

# electrs: clone -b blake2b, then (RocksDB needs cstdint on new toolchains)
CC=clang CXX=clang++ CXXFLAGS="-include cstdint" cargo build --locked --release
./target/release/electrs --conf config.toml     # network = "testnet4", daemon_rpc_addr = 127.0.0.1:48342

# shim
npm install
node shim/server.mjs --port 3006 --electrum 127.0.0.1:50001 --rpc 127.0.0.1:48342 --cookie ~/.bitcoin/testnet4/.cookie

Then open the wallet with ?api=http://127.0.0.1:3006/api. Browsers allow an https page to call http://127.0.0.1, so the hosted wallet works against a local shim. The shim serves address/:a, address/:a/utxo, address/:a/txs, tx/:id, v1/fees/recommended, blocks/tip/height and POST tx, with open CORS and no auth. Testnet only, keep it on localhost or behind a proxy.

Files

• index.html — the wallet. Preact plus htm, no build step, dependencies from esm.sh via an import map.
• bitcoin.js — keys, bech32m, taproot addresses, transaction building and signing.
• unified.js — the unified sighash message for all four script types, plus a raw transaction parser.
• unified-sighash.md, unified_sighash.json — the spec and the 166 test vectors, copied verbatim from the Knots tag.
• test.mjs — runs every vector and a build, sign, verify round trip.
• shim/server.mjs — Esplora-lite over electrs and Knots RPC, see above.

Test

npm install
npm test

Origin

Derived from testcoin.org, the Bitcoin testnet4 wallet, with the signing path changed to the unified sighash and the backend pointed at the BLAKE2b chain.

Part of awesome-bitcoin-blake.