Bitcoin Improvement Proposals (BIPs)

A Bitcoin Improvement Proposal (BIP) is a formal design document for introducing features, standards, or process changes to Bitcoin. BIPs provide a clear, public record of proposed changes so that developers, node operators, and other participants can review, discuss, and implement them consistently. The process is deliberately open and conservative. Anyone can write a BIP, but adoption depends on voluntary implementation by software and node operators.

BIPs are numbered sequentially and categorized by type: Standards Track (protocol or consensus changes), Informational (guidelines or general information), and Process (changes to Bitcoin processes outside the protocol itself). A BIP moves through stages including Draft, Proposed, Final, and sometimes Rejected or Deferred. There is no central authority that “approves” a BIP. Consensus emerges when a critical mass of nodes and software implement the change.

Key participants include the BIP author(s), reviewers from the broader developer community, and ultimately the operators of full nodes who choose which software to run. The Bitcoin Core repository and associated discussion forums serve as the primary coordination points, but no single group controls the outcome.

Most Important BIPs

• BIP 32 — Hierarchical Deterministic Wallets. Introduced the standard for generating a tree of keys from a single seed, now used by virtually every modern wallet.
• BIP 39 — Mnemonic code for generating deterministic keys. Defined the 12/24-word seed phrase standard that allows human-readable backup of private keys.
• BIP 44 — Multi-account hierarchy for deterministic wallets. Extended BIP 32 with a standard path structure for different coin types and accounts.
• BIP 141 / 143 / 144 — Segregated Witness (SegWit). Separated signature data from transaction data, fixed transaction malleability, and increased effective block capacity. Activated in 2017.
• BIP 340 / 341 / 342 — Schnorr signatures and Taproot. Introduced more efficient and private signature aggregation and a new script system. Activated in November 2021.
• BIP 125 — Opt-in Replace-by-Fee. Defined a signaling method for allowing a higher-fee transaction to replace an unconfirmed one.
• BIP 174 — Partially Signed Bitcoin Transactions (PSBT). Created a standardized format for multi-party transaction coordination, widely used by hardware wallets and multisig setups.

These BIPs illustrate how Bitcoin evolves: through public proposals, careful review, and voluntary adoption by the network’s participants rather than by decree.