Congestion Control Tree

A congestion control tree is a proposed transaction structure, enabled by a template-commitment opcode such as OP_CHECKTEMPLATEVERIFY, that lets a payer commit to many future payouts using a single small on-chain transaction during periods of high fees. Recipients are assured by the commitment that they will be paid, while the actual payout transactions are broadcast later when block space is cheaper. This is a proposed use of an experimental opcode and is not available on Bitcoin's base layer today.

How it works

Instead of broadcasting one large transaction with many outputs at a high fee rate, the payer publishes a compact transaction whose single output commits, via a hash, to a follow-up transaction. That follow-up can in turn commit to further transactions, forming a tree whose leaves are the individual recipients. Every hash in the tree chains back to the original commitment, so the entire structure is fixed in advance and cannot be altered.

Why a tree

A flat batch forces everyone to confirm at the same time and fee. A tree lets each branch carry its own fee rate, so an urgent recipient can expand their branch quickly (paying more, optionally with child-pays-for-parent), while a patient recipient waits for the mempool to clear and redeems cheaply. Each participant chooses their own urgency. The same mechanism underpins related ideas such as payment pools, where several parties share a UTXO with pre-planned split paths.

This pattern depends on OP_CHECKTEMPLATEVERIFY and is part of the broader covenant design space. D-Central describes it as a proposed application, not a shipped feature.