Definition
A transaction accelerator is a tool that helps a stuck Bitcoin transaction confirm sooner than its fee rate would otherwise allow. When a transaction underpays for current mempool conditions, miners pass it over and it can languish for hours or days. An accelerator nudges it toward the front of the queue.
How accelerators work
Some mining pools historically offered to submit a low-fee transaction directly to their own block templates, effectively prioritizing it without changing its on-chain fee. A more robust, self-sovereign approach is to bump the fee yourself. Replace-by-Fee lets a sender rebroadcast the same transaction with a higher fee if it was flagged as replaceable. Child-Pays-for-Parent lets a recipient spend an unconfirmed output in a new, high-fee child transaction, incentivizing miners to mine both together to collect the combined fees.
What to weigh
Third-party accelerators vary in reliability, may charge fees, and require trusting an external operator. Fee-bumping techniques are trustless because they rely only on standard Bitcoin transaction rules, which is why self-custodial wallets increasingly expose them directly. Crucially, a transaction must be replaceable or have a spendable change output for these methods to apply; otherwise the only option is to wait.
See unconfirmed transaction and confirmation time for context.
In Simple Terms
A transaction accelerator is a tool that helps a stuck Bitcoin transaction confirm sooner than its fee rate would otherwise allow. When a transaction underpays…