Bolt

• Name: Bolt
• URL: https://docs.boltprotocol.xyz/
• Category: out-of-protocol proposer-commitment infrastructure / Ethereum preconfirmation protocol / PBS constraints-and-proof extension
• Tags: ethereum-ecosystem
• Summary: Bolt is proposer-commitment plumbing for Ethereum’s PBS supply chain. Users ask proposers for commitments, proposers turn those promises into constraints, builders return proof-carrying bids, and enforcement stays optimistic rather than protocol-native. Useful mechanism note, not a category anchor for based rollups.
• What it does:
  • Lets users request commitments such as preconfirmations from Ethereum block proposers
  • Adds a commitments API for user-to-proposer interaction and a constraints API that extends builder / relay communication in the PBS pipeline
  • Allows proposers or delegated entities to submit signed transaction constraints for specific slots, including top-of-block or atomic-bundle style requirements
  • Requires builders to produce bids with inclusion proofs so proposers can verify that committed transactions are present before signing the block header
  • Provides a sidecar / mev-boost style integration path plus contracts for proposer registration and permissionless dispute resolution around attributable faults
  • Includes fallback logic where proposers can self-build if relay responses do not satisfy the committed constraints
• Key claims:
  • Bolt’s introduction page says the protocol enables Ethereum block proposers to provide credible commitments about block contents and explicitly frames preconfirmations and inclusion lists as the motivating primitives
  • The docs say Bolt v1 enables sub-second preconfirmations on Ethereum through proposer commitments, which makes it a useful comparison class for any system trying to sell faster confirmation without waiting for protocol-native changes
  • Bolt’s docs say the system is out-of-protocol and leverages restaking for economic assurances, operating in an optimistic failure mode where proposers can breach commitments but are penalized when they do
  • The repository README says Bolt is fully compatible with PBS and is implemented as a forked / extended MEV-Boost stack, which is analytically important because Bolt is trying to change the execution supply chain without replacing it wholesale
  • The technical flow says proposers forward committed transactions to relays as constraints, builders subscribe to those constraints and return bids with inclusion proofs, and proposers locally verify proofs before signing; this turns “preconfirmation” into a pipeline redesign rather than a simple promise message
  • The builder API docs show Bolt also standardizes delegation and revocation of constraint-submission rights, which means authority over commitments can be reassigned instead of remaining hardwired to one validator key path
  • The fallback-to-self-build path matters because it reveals where ultimate execution authority still sits: proposers can reject invalid relay proofs and build directly, preserving proposer accountability at the edge of the PBS market
  • The strongest comparison frame is not generic fast-confirmation UX; it is “an out-of-protocol constraints market layered on top of PBS, with proposer accountability backed by economic penalties and proof-carrying bids”
• Whitepaper: No canonical standalone Bolt whitepaper or litepaper surfaced in this pass. The clearest current sources of truth were the official docs, the repository README, and the builder-API specification pages; see ../whitepapers/bolt-primary-sources-2026-05-10.md.
• Sources:
  • https://docs.boltprotocol.xyz/
  • https://docs.boltprotocol.xyz/overview/introduction
  • https://docs.boltprotocol.xyz/technical-docs/api/builder
  • https://github.com/chainbound/bolt
  • https://raw.githubusercontent.com/chainbound/bolt/main/README.md

Internal linkages

• Strongest upward comparison points: puffer-preconf and spire.

Control surface

• Authority sits in who can sell commitments, who can submit or delegate constraints, which relays and builders support proof-carrying bids, and what penalty path actually matters when a promise breaks.

• Read Bolt as Ethereum supply-chain middleware, not as a based-rollup center.

• Last reviewed: 2026-06-16 UTC