1. Overview
  2. System Overview


System Overview

Technical overview of the primev protocol.


Block Builder - Refers to a builder instance at a protocol level represented by a single address.

Provider - is the organization that owns private keys associated with block builders. A single provider can own multiple private keys, and thus control multiple block builders.

User - is the entity that currently consumes data from the Primev network and is identified by their address.

builder-boost - The name of the client software that sits as a sidecar module and allows providers to enable Primev.


A key starting point for the system is for provider nodes to relay block templates/execution payloads to builder-boost, which providers will self-host.


Detailed Actor Interactions

actor overview

Block Builder Interface Modification

Example commit for Relay modifications can be seen here.

        type IRelay interface {
	SubmitBlock(msg *boostTypes.BuilderSubmitBlockRequest, vd ValidatorData) error
	SubmitBlockCapella(msg *capellaapi.SubmitBlockRequest, vd ValidatorData) error
	**+ SubmitBlockPrimev(msg *capellaapi.SubmitBlockRequest) error**
	GetValidatorForSlot(nextSlot uint64) (ValidatorData, error)
	Start() error


We use the relay API to simplify the integration process for providers. Similar to the sending of block to a relay, we suggest adding a function named SubmitBlockPrimev to the relay interface of your Block builder Node Implementation, so that it can send payloads to builder-boost.

Processing Block Templates

primev overview

Notice in the diagram above, the flow of templates follow the following pattern:

  1. Block bids are sent to Flashbots relay
  2. Block templates are sent to builder-boost to compute execution data
  3. Execution data is sent to the Primev network

builder-boost Overview

Directory Structure Overview

β”œβ”€β”€ cmd # Contains Entrypoints
β”‚Β Β  β”œβ”€β”€ boost # Entrypoint for main boost utility
β”‚Β Β  └── searcher # Entrypoint for searcher emulator
β”œβ”€β”€ integrationtest
β”‚Β Β  β”œβ”€β”€ searcher_test.go # Tests focused on searcher connections
β”‚Β Β  └── test_payloads.go
β”œβ”€β”€ pkg
β”‚Β Β  β”œβ”€β”€ api.go # HTTP Server Endpoints
β”‚Β Β  β”œβ”€β”€ boost.go # Business Logic to compute execution data
β”‚Β Β  β”œβ”€β”€ contracts # Bindings for Contract RPC Calls
β”‚Β Β  β”œβ”€β”€ rollup # Wrapper & Business logic to consume searcher payments data
β”‚Β Β  β”œβ”€β”€ service.go
β”‚Β Β  └── worker.go


Authentication & Authorization

The Boost API Authenticates two different types of entities:

  1. The Provider running builder-boost
  2. Users

Provider running builder-boost

The Provider uses password based authentication to identify itself to its builder-boost Instance. The Password should be included in the X-Builder-Token header when making a post to /primev/v1/builder/blocks to submit templates.

Only the provider with the password set in builder-boost Environment variable will be authorized to send blocks to builder-boost.

User authentication

User authentication has additional steps due to privacy requirements. You can learn more in the user privacy section.

Authorization and Authentication are split into two parts.

The authorization state of users is stored in the registry contract, where as authentication occurs via signatures.

After authenticating, the user receives a unique token that it must store in the registry contract, along with its payment to authorize its connection to receive execution data from the provider.

The diagram below showcases the high-level flow:

searcher auth now

Optional - Dual Authentication of Block Builders (Coming Soon)

We plan to add a step in which a provider can provide a self-signed URL, to authenticate the URL as owning the Address being connected to (Note: This defers the security of the authentication to the DNS resolution of the URL or Public Key Infrastructure (PKI)). It would be up to the Searcher to verify the signature. However the current model inherits existing block builder trust assumptions.

searcher auth future

General Security Model

There’s an implied trust in providers due to their ability to store the private bundle payloads of searchers. The current version of builder-boost makes honesty assumptions that the provider provides correct and accurate execution data it sends to a user. The Primev team has planned a protocol integrity layer to remove these assumptions in the future.

Registry Contract Details

The registry contract can be thought of as the authorization destination for the Primev protocol. It allows providers to set the minimum payment requirement to authorize a connection.


  1. Endpoint: /health
    • Method: GET
    • Description: Checks the health of the service and provides information about the connected searchers and the worker's heartbeat.
    • Handler Function: handleHealthCheck
  2. Endpoint: /builder
    • Method: GET
    • Description: Retrieves the provider ID.
    • Handler Function: handleBuilderID
  3. Endpoint: /commitment
    • Method: GET
    • Description: Gets the commitment to the provider by user address.
    • Handler Function: handleSearcherCommitment
  4. Endpoint: /primev/v1/builder/blocks
    • Method: POST
    • Description: Submits a block to be processed by the service.
    • Handler Function: submitBlock
  5. Endpoint: /ws
    • Method: GET
    • Description: Establishes a WebSocket connection for a user to receive execution data.
    • Handler Function: ConnectedSearcher