Signet

Signet is a bitcoin test network, defined in BIP 325 and supported in Bitcoin Core since 2020, in which valid blocks must carry a signature from designated operators in addition to minimal proof-of-work. Its coins are worthless by design, and its purpose is to give developers a public testing environment that behaves predictably.

Why it matters

The older public test network, testnet, uses real but easy proof-of-work, which makes it chaotic: hobbyist miners with idle hardware cause wild difficulty swings, multi-block reorganizations, and long gaps between blocks, and its coins have periodically acquired black-market value, undermining the premise. Signet's signature requirement removes the mining lottery, so blocks arrive on a steady schedule and reorganizations happen only when deliberately staged. That reliability matters for teams testing wallets, exchanges, and Lightning software against realistic network conditions.

How it works

Each signet is defined by a challenge script specifying who may sign blocks, so anyone can launch a custom signet for private testing, and the widely used default signet is signed by two maintainers. Ordinary transactions require no signatures beyond the usual, only block production is permissioned, and faucets distribute free coins to developers. Signet also serves as a staging ground for proposed soft forks, hosting activated versions of features still under debate for mainnet, which lets engineers exercise code paths years before any real deployment decision.