Definition
Signet is a Bitcoin test network defined in BIP 325 that adds an extra signature requirement to block validation. Rather than relying purely on competitive proof-of-work, each valid block must satisfy a predefined block script, typically a k-of-n multisig held by the network's operators. The result is a test chain that behaves far more like mainnet than testnet does.
Why Signet exists
Public testnet suffers from wild swings: long stretches with no blocks, then bursts of hundreds of blocks, plus deep chain reorganisations driven by sporadic hash power. Signet replaces that chaos with a predictable amount of unreliability. Operators can produce blocks on a steady cadence (for example a 10-minute average) and can deliberately trigger rare-but-expected events such as a 6-block reorg, which makes it ideal for teaching, wallet testing, and protocol development.
Default and custom signets
A default global Signet ships with Bitcoin Core and is reached with the -signet flag on ports 38333 (P2P) and 38332 (RPC). Anyone can also spin up a custom signet by supplying their own challenge script via -signetchallenge and seed nodes via -signetseednode. SegWit is always active, and the network message header is derived from the challenge so distinct signets stay isolated.
Signet sits between the open chaos of Testnet and the fully private control of Regtest.
In Simple Terms
Signet is a Bitcoin test network defined in BIP 325 that adds an extra signature requirement to block validation. Rather than relying purely on competitive…