Bitcoin Testnet 5 Mines Its Genesis Block Through a Public Pool

Bitcoin's next testing ground has its first block. Miners created the Testnet 5 genesis block on November 14, 2026, using SHA-256 proof of work, opening a separate environment for testing mining pools, nodes and future consensus rules. Developer Anthony Towns published the block data with a header timestamp of 05:03:13 UTC. The test coins are not bitcoin and have no monetary value.

The launch answers a longstanding irritation with Bitcoin testing. Older test networks carried block-production exceptions that allowed bursts of low-difficulty blocks and competing tips, which made them poor stand-ins for mainnet behavior. BIP 95, still a draft, proposes retiring Testnet 4 for a network closer to mainnet mining, with different genesis data and an independently maintained chain state.

The first block was deliberately not a private head start. Towns arranged a publicly accessible ckpool instance before launch, so anyone with SHA-256 mining hardware could attempt the genesis block. The pool initially advertised a zero-percent fee and waited for mainnet block 975,744 before issuing genesis work, a design Bitcoin Optech described on November 13 as an attempt to prevent a private mining head start.

The difficulty floor is the other break. Testnet 5 raises its minimum difficulty roughly one millionfold against Testnet 4, which makes dedicated ASIC hardware the practical route for initial mining and limits the sudden block floods that plagued easier test networks. Developer Steven Roose announced the live chain and reported 166 blocks in its first hour, alongside a P2Poolv2 deployment.

The genesis block also anchors itself to mainnet history. Its coinbase records the November 14 date, block height 975,744 and that block's mainnet hash, committing the new chain to information that couldn't exist before the reference block did. The commitment doesn't merge the two ledgers, transfer bitcoin, or make Testnet 5 rewards redeemable on mainnet.

The rule set starts strict. BIP 95 eliminates the old 20-minute minimum-difficulty exception and activates the proposed BIP 54 consensus-cleanup rules from block one on Testnet 5 — test-network rules that don't activate BIP 54 on mainnet. The remaining work is infrastructure: Towns lists Bitcoin Core integration, DNS seeds, faucets and explorers as outstanding, and a Libbitcoin mailing-list update on November 14 identified two connected nodes. It's a publicly checkable starting record, not a finished network.