`insufficient-feerate`


Category	Mempool policy
Surfaces as	HTTP 409 (`rejected by node policy`) when submitted to a node; not a consensus failure
problem+json `code`	`insufficient-feerate`

Where it is defined

§13 Mempool policy (not consensus): its fee rate exceeds every directly conflicting transaction's [insufficient-feerate];

See the error model for the RFC 9457 response shape.