MEV-Relay for Builders

The Vouch MEV-Relay is the neutral auction house of the stack. Builders assemble blocks and bid for the right to have a validator propose them; the highest valid bid wins. More builders bidding means better prices for validators.

• Permissionless and credibly neutral — any builder can register and compete. No allowlist, no favourites.
• Open to every builder — including Vouch's own builder, BlockFerret, which competes on the same terms.
• Verifiable in public — every delivered payload is listed on the delivered-blocks explorer.

Validators connect through the MEV-Boost sidecar. This page is for builders and searchers who want to bid for blockspace.

Connect your builder

Everything below is available publicly. The two values you need — the relay endpoint and the relay BLS public key — are shown at the top of the /mevblocks page.

Item	Value
Relay endpoint	https://boost-relay.vouch.run
Relay BLS pubkey	0xa6b974cbc17ce9c37b5f9796e167455d22882f2ca662c19379b0b9c476b1fbe745c19006444b653f9fb8409ffda9a450
Relay URL	https://0xa6b974cbc17ce9c37b5f9796e167455d22882f2ca662c19379b0b9c476b1fbe745c19006444b653f9fb8409ffda9a450@boost-relay.vouch.run
Submit blocks	POST /relay/v1/builder/blocks
Validator registrations	GET /relay/v1/builder/validators

What you need to supply

• Your own BLS bid-signing key. The builder generates and holds this key; it signs every bid trace so the relay can attribute and validate your submissions.

• A beacon endpoint your builder can subscribe to for head and payload_attributes events.

• PulseChain chain values for your builder configuration:

  Setting	Value
  genesis_fork_version	0x00000369
  bellatrix_fork_version	0x0000036b
  genesis_validators_root	0x3357ba0018a2582aeabe4ae847aa17d50a3a99aaeb66293c01f80a83aecd0c90
  seconds_in_slot	10
  slots_in_epoch	32

Builder flags

On a Flashbots-style builder these map to (for example):

--builder \
--builder.secret_key=<YOUR_BUILDER_BLS_KEY> \
--builder.remote_relay_endpoint=https://boost-relay.vouch.run \
--builder.beacon_endpoints=http://<YOUR_BEACON_NODE>:5052 \
--builder.genesis_fork_version=0x00000369 \
--builder.bellatrix_fork_version=0x0000036b \
--builder.genesis_validators_root=0x3357ba0018a2582aeabe4ae847aa17d50a3a99aaeb66293c01f80a83aecd0c90 \
--builder.seconds_in_slot=10 \
--builder.slots_in_epoch=32

Registration and priority

• Registration is permissionless. The first time your builder submits an accepted block, the relay registers it automatically at default (low) priority. There is no signup step.
• Higher priority / optimistic submission / collateral are arranged with Vouch during onboarding. Optimistic mode skips per-block simulation for bids up to your posted collateral; above it, blocks are simulated synchronously. Reach out via the support channels below.

Check you're connected

• Watch the Builder column on /mevblocks — your short pubkey appears when your blocks deliver.

• Or query the data API for your builder:

  curl -s "https://boost-relay.vouch.run/relay/v1/data/bidtraces/builder_blocks_received?builder_pubkey=<YOUR_BUILDER_PUBKEY>"

Searchers: submit bundles

If you run a searcher, you can submit MEV bundles directly to the builder over a single, narrow edge. (Searchers and builders are the same audience here — a bundle is just a pre-packaged slice of a block.)

• Endpoint: POST https://builder.vouch.run — JSON-RPC eth_sendBundle only.
• Auth: header X-Flashbots-Signature: <0x-address>:<0x-signature> (the standard Flashbots signing scheme: keccak256 of the raw request body, EIP-191 personal_sign). The recovered address must be on the allowlist.
• Onboarding: send your signing address to the Vouch team to be added to the allowlist (see support below).
• Notes: blockNumber is required and must be an absolute block; replacementUuid replaces an earlier bundle for the same target. PulseChain's base fee is high, so dust bundles whose payment is below the base-fee burn are rejected.

Public transparency

The /mevblocks explorer shows every delivered payload — builder, block, value delivered, block fees, and MEV uplift — with filtering, sorting, and pagination. You can also pull the same data programmatically:

Endpoint	Purpose
GET /relay/v1/data/validator_registration?pubkey=<pubkey>	A validator's registration.
GET /relay/v1/data/bidtraces/proposer_payload_delivered?proposer_pubkey=<pubkey>	Blocks delivered to a proposer.
GET /relay/v1/data/bidtraces/builder_blocks_received?builder_pubkey=<pubkey>	Blocks received from a builder.
GET /relay/v1/builder/validators	Current validator registrations (for builders).

Resources

• Vouchrun/mev-boost-relay — the relay (pulse branch).
• Vouchrun/go-pulse-builder — a reference builder implementation.
• Delivered-blocks explorer — live relay activity.
• MEV-Boost (Validators) — how validators connect.
• BlockFerret — Vouch's own builder.

Support

• Telegram