B3Chain Testnet

Live status #

Poll of /testnet-status.json, refreshed every 60 seconds. The exporter source is contrib/testnet/status-monitor/. Cards show “n/a” when the corresponding upstream is unreachable; the whole panel turns warning-yellow when the JSON is more than 5 minutes stale.

Last 5 blocks

1. Connect a node #

Build (or download) b3chaind from github.com/b3chain/b3chain on the b3chain-main branch (or any released v0.1.x-testnet tag), then run:

b3chaind -chain=test

That's it. The DNS seed at testnet-seed.b3chain.org returns the operator-run seed nodes (seed1 = 166.88.4.250, seed2 = 151.158.1.22, seed3 = 151.158.1.60); your node will connect and start syncing the chain. See the runbook §2 for the recommended b3chain.conf with explicit addnode= lines.

Connection parameters

2. Get test coins #

Generate a new bech32 address with your wallet:

b3chain-cli -chain=test getnewaddress "" bech32
# returns tb3...

Paste it into the faucet at faucet.b3chain.org. The faucet hands out 0.5 tB3C per request, with a 24-hour cooldown per IP and per destination address. A JSON status endpoint is at /status.

The faucet is a small Flask service in the public source tree: contrib/testnet/faucet/app.py.

3. Explore the chain #

A live block explorer is at explorer.b3chain.org. It is a deployment of btc-rpc-explorer pointed at one of the operator-run testnet nodes — nothing custom, so any compatible explorer can do the same.

Programmatic status feeds:

• /testnet-status.json — structured live status (the panel above), updated every 60 s
• /testnet-status.txt — human-readable seed snapshot
• Explorer API: https://explorer.b3chain.org/api/blocks et al. (see runbook §9)

4. Mine blocks #

Three options, in increasing order of hashrate. All three target the same algorithm: B3PoW-Scratch v1.1.1 (post-F-1, live since genesis). The retired BLAKE3(BLAKE3(header)) algorithm is not accepted on any b3chain network — the pool and every full node reject those shares.

Solo mining with the reference CPU miner

b3chain-cpuminer.py defaults to B3PoW-Scratch v1.1.1. The --legacy-blake3d flag exists only for cross-checking historical headers against the retired double-BLAKE3 algorithm and will not produce valid B3Chain shares — the miner emits a stderr warning when that flag is passed.

Anyone can mine on testnet. The reference CPU miner talks to your local node via JSON-RPC and submits valid blocks via submitblock.

pip install blake3                              # required by the B3PoW-Scratch Python reference
b3chain-cli -chain=test getnewaddress "" bech32
# tb3...your-address...

python3 contrib/miner/b3chain-cpuminer.py \
    --rpcconnect=127.0.0.1 \
    --rpcport=18534 \
    --rpcuser=USER \
    --rpcpassword=PASS \
    --coinbaseaddr=tb3...your-address...

Testnet uses an early-difficulty-guard regime for the first 10 000 blocks (nEarlyDifficultyGuardHeight in src/kernel/chainparams.cpp), so a single CPU thread can produce blocks at roughly the 10-minute target.

Pool mining via Stratum

The public pool at stratum+tcp://pool.b3chain.org:3333 validates every share against the canonical B3PoW-Scratch v1.1.1 algorithm exactly the way b3chaind does. Reward scheme is PPLNS over the last 4032 weighted shares; pool fee is 1%. Usernames are <email>.<workerName> for verified accounts at pool.b3chain.org, or <tb3address>.<workerName> for anonymous miners.

python3 contrib/miner/b3chain-cpuminer.py \
    --stratum stratum+tcp://pool.b3chain.org:3333 \
    --user alice@example.com.cpu1 --pass x \
    --threads 2 --json-log shares.jsonl

Worker name / share format / vardiff / payout policy are documented in runbook §7. The wire-protocol implementer contract is in contrib/testnet/pool/docs/STRATUM-PROTOCOL.md.

B3Miner-1 FPGA

The B3Miner-1 reference FPGA mining card (XCKU5P + ESP32-S3 + Ethernet) is the intended high-end miner for B3PoW-Scratch. Build and flash instructions are in contrib/miner/b3miner-firmware/README.md. Point the card at the same Stratum endpoint above; the onboard dashboard handles the credentials.

After bitstream configuration the firmware reads REG_ID over SPI; it must return 0xB3110002 (v1.1.1 build 0002 — the F-1 fix bumped this from the original 0xB3110001 build 0001). Older bitstreams mine the pre-F-1 v1.1.0 algorithm and are rejected by the v1.1.1 firmware.

What about a GPU miner?

There isn't one, and there isn't going to be one on this tree. B3PoW-Scratch is GPU-hostile by design: its 1 MiB sequential, data-dependent scratchpad destroys GPU throughput. The historical CUDA tree at contrib/miner/b3chain-gpuminer/ is deprecated: it still compiles, but it only computes the retired double-BLAKE3 algorithm and is kept only as a worked example of the Stratum V1 + JSONL pipeline. It will not produce valid mainnet or testnet shares.

5. Operator notes #

The seed network is intentionally small at bootstrap: one operator-run host (seed1) carries the pool, faucet, explorer, and status monitor in addition to b3chaind; seed2 and seed3 are seed-only nodes in different geographic regions for redundancy. Anyone can join at any time — just run b3chaind -chain=test.

Repository layout

Chain-recovery tools (M-14)

Every seed runs the v1.1.3 M-14 operator-pinned chain-recovery RPCs (finalizeblock, unfinalizeblock, parkblock, unparkblock, getfinalizedblockhash) and, in production, the 51attack-watch.py monitoring daemon described in doc/security/51-MONITORING-OPS.md. The end-to-end response procedure for a deep reorg, hashrate drop, or pow-budget storm is in RESPONSE-RUNBOOK-51ATTACK.md; a one-page summary of both lives at testing/operator-tools.html.

6. Found a bug? #

Testnet bugs are exactly what we want before mainnet. Report any consensus oddity, reorg longer than 2 blocks, sync stall, RPC inconsistency, or wallet weirdness via the channels described in /testing/reporting.html, or file an issue directly at github.com/b3chain/b3chain/issues. Include the testnet block height, your node version (getnetworkinfo), and the journal log (journalctl -u b3chaind-testnet --since '1 hour ago'). Security disclosures go to security@b3chain.org.