BIP 44

BIP-44 defines the standard derivation-path structure for hierarchical deterministic wallets. It's the convention that lets you back up a seed phrase in one wallet and restore the same accounts in any other BIP-44-compliant wallet.

The path structure is:

m / purpose' / coin_type' / account' / change / address_index

Concretely, the first receive address of the first Bitcoin account would be:

m / 44' / 0' / 0' / 0 / 0

What each level means:

• 44' - purpose number, fixed at 44 for BIP-44-style derivation. (Other purposes exist: 49' for P2SH-wrapped SegWit, 84' for native SegWit, 86' for Taproot.)
• 0' - coin type, where Bitcoin is 0. Other chains have their own numbers per SLIP-44.
• 0' - account number. Lets you have separate "accounts" within one wallet (e.g., savings vs spending).
• 0 - change indicator. 0 = receive addresses, 1 = internal change addresses.
• 0 - address index. Incremented for each fresh address.

The apostrophes mean "hardened" derivation - a level that can't be derived from a parent extended public key, only from the private one. BIP-32 hardens the account level for a reason: an extended public key plus any one non-hardened private key below it gives away the parent extended private key, so with the account level hardened (and the two levels above it), a leak inside one account can't reach the master key or the other accounts.

BIP-44 is the spec that turned "back up your seed phrase" into a portable, reliable, multi-implementation standard. Most seed-phrase wallets follow it or one of its siblings for other address types (BIP-49, BIP-84, BIP-86), all of which the BIPs repository marks as deployed. See Hierarchical Deterministic Wallet for the underlying BIP-32 framework this builds on.