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TERM_DEF // UPGRADES_BIPS / BIP_133_FEE_FILTER_MESSAGE
BIP 133 (FEE
FILTER MESSAGE)
BIP 133 (Fee Filter Message). P2P message advertising a peer's minimum-feerate filter.

This page sits in the Upgrades & BIPs section — The proposal process and the major upgrades that shaped Bitcoin. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.
WHAT_BIP_133_FEE_FILTER_MESSAGE_IS
BIP 133 (Fee Filter Message) — at a glance
UPGRADES
BIP 133 — "Fee Filter Message" is a proposal in the Networking family, first published in 2016 with status final. P2P message advertising a peer's minimum-feerate filter. Its technical mechanism: feefilter message carrying a minimum sat/kvB; sender skips lower-fee inv. reduces unnecessary mempool relay; in every Core release since 0.13
Why it exists
DESIGN
BIP 133 (Fee Filter Message) exists to solve a specific problem: let a peer tell relay only tx whose feerate is above some threshold. Without a written, numbered spec, every wallet and node implementer would interpret the requirement differently — and Bitcoin's value depends on every implementation agreeing exactly. BIP-133 is the single source of truth for this concern, so any new client built today can match the behaviour of every client built since 2016.
HOW_IT_WORKS
Mechanism
HOW IT WORKS
Mechanically, BIP-133 feefilter message carrying a minimum sat/kvB; sender skips lower-fee inv. Adoption today: reduces unnecessary mempool relay; in every Core release since 0.13.
1. Author drafts BIP-133 against the BIP-2 template — abstract, motivation, specification, rationale. 2. The text + a reference implementation are posted on the bitcoin-dev list and as a PR to bitcoin/bips. 3. Reviewers tear it apart: ambiguities, security concerns, edge cases, interaction with prior BIPs. 4. Once stable, the BIP editor merges it; it gets a number (BIP-133) and the status "draft" or "proposed". 5. Implementations land in Bitcoin Core / wallets / other clients. For consensus changes: activation parameters chosen. 6. After deployment + adoption, BIP-133 is promoted to "final"; deprecated proposals get "replaced" or "withdrawn".
WORKED_EXAMPLE
BIP-133 — quick reference card
EXAMPLE
BIP number : 133 Title : Fee Filter Message Area : Networking First published: 2016 Status : final Fork class : no Motivation : let a peer tell relay only tx whose feerate is above some threshold. Mechanism : feefilter message carrying a minimum sat/kvB; sender skips lower-fee inv. Where it shows up : reduces unnecessary mempool relay; in every Core release since 0.13. Read the spec : https://github.com/bitcoin/bips/blob/master/bip-0133.mediawiki
KEY_PROPERTIES
OPT-IN
No authority can force a BIP on anyone. Adoption depends entirely on whether the change is genuinely useful.
NUMBERED
Stable numeric reference — BIP-133 means the same thing across every wallet, miner, and node that has read this spec.
NON-CONSENSUS
BIP-133 is not a consensus rule — clients can implement it without coordinating with the network at large.
DEPLOYED
Implementations of BIP-133 are in production. The behaviour is observable on mainnet today.
COMMON_PITFALLS
Things that catch people out
PITFALLS
  • Don't confuse "draft" / "proposed" / "final" status — read the BIP header before relying on it in production.
  • The BIP number is just an editorial counter — it doesn't imply correctness or stability. Always cross-reference with the latest bitcoin/bips repo.
RELATED_CONCEPTS
Other terms from Upgrades & BIPs — click any to read its page:
Segregated Witness (SegWit, BIP 141) Taproot (BIP 341) Tapscript (BIP 342) Schnorr (BIP 340) BIP Process Soft Fork Activation MASF (Miner-Activated Soft Fork) UASF (User-Activated Soft Fork)
TERMINOLOGY_INDEX
TERMINOLOGY
BIP 133 (Fee Filter Message)
P2P message advertising a peer's minimum-feerate filter.
Segregated Witness (SegWit, BIP 141)
The 2017 upgrade separating witness-data/">witness data, fixing tx malleability, and introducing weight units.
Taproot (BIP 341)
The 2021 upgrade introducing key-aggregable schnorr-signatures/">Schnorr signatures and Merkleized script trees.
Tapscript (BIP 342)
Script-language updates accompanying Taproot — new opcodes, removed limits.
Schnorr (BIP 340)
The Schnorr signature spec adopted by Taproot.
BIP Process
The community workflow for proposing, discussing, and tracking changes to Bitcoin.
Soft Fork Activation
The mechanism (versionbits, MASF, UASF, Speedy Trial) by which soft forks turn on.
MASF (Miner-Activated Soft Fork)
Activation triggered by miner signaling in block versions.