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 the Switch.win × Vouch alliance 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 who want to bid for blockspace. Searchers submitting bundles should see Searchers (Submit Bundles).

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, submit your bundles to the Vouch Builder. See Searchers (Submit Bundles) for the endpoint, signature authentication, onboarding, and limits.

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.
• Searchers (Submit Bundles) — submit bundles to the Vouch Builder.
• BlockFerret — the Switch.win × Vouch alliance builder.

Support

• Telegram