Glossary.
Short definitions for the Bitcoin, x402, Web3, and Core v31 terms used across FastPath docs and API responses.
- x402
- An HTTP 402 payment protocol. FastPath uses it so bots can pay per API call with USDC and no API key.
- EVM
- Ethereum Virtual Machine. FastPath lets EVM-style clients ask Bitcoin questions through familiar JSON-RPC patterns.
- sat/vB
- Satoshis per virtual byte, the common Bitcoin fee-rate unit.
- UTXO
- Unspent transaction output. Bitcoin wallets spend UTXOs rather than account balances.
- Mempool
- The set of valid unconfirmed Bitcoin transactions known to a node.
- RBF
- Replace-By-Fee, a policy that lets a wallet replace an unconfirmed transaction with a higher-fee version.
- CPFP
- Child-Pays-For-Parent, a fee bump strategy where a child transaction helps confirm its parent.
- Core v31
- Bitcoin Core v31-style node data used by FastPath for mempool package and template intelligence.
- Template check
- A comparison against FastPath's live cached optimizer and baseline template signals.
- Non-custodial
- FastPath can analyze, plan, and relay signed transactions, but it never holds private keys or signs transactions for users.