aid: harmonic-gg
name: Harmonic GG
description: >-
  Harmonic is a highly-configurable, open block-building system for Solana. Validators
  keep full autonomy over how their blocks are built, choosing their own block builder
  and scheduling strategy (FBA, FIFO, MREV, or custom) while the block engine streams
  the constructed block for broadcast. A Remote TPU aggregation layer collects proposals
  from independent builders in real time, HFT-router style, to raise validator revenue
  and strengthen network decentralization. Searchers submit atomic transaction bundles
  over a gRPC interface that is backwards-compatible with Jito's searcher protos, with
  revert protection, bundle privacy, and tips paid as ordinary priority fees (no protocol
  cut). Harmonic raised a $6M seed round led by Paradigm.
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://harmonic.gg/api/og?v=home
url: https://raw.githubusercontent.com/api-evangelist/harmonic-gg/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- paradigm
x-tier: enriched
x-tier-reason: portfolio-lead-enriched
x-sector: blockchain-infrastructure
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-19'
tags:
- Company
- Blockchain
- Solana
- Block Building
- MEV
- Validator
- Searcher
- Infrastructure
- gRPC
- DeFi
apis:
- name: Harmonic Searcher API (gRPC)
  description: >-
    gRPC bundle-submission interface for searchers. Authenticate with a Solana keypair
    (challenge-response to Bearer tokens), then submit atomic transaction bundles with
    revert protection. Backwards-compatible with Jito's searcher protos; tips are
    priority fees with no protocol cut. Requires a whitelisted searcher pubkey.
  humanURL: https://docs.harmonic.gg/searchers/harmonic-bundles
  baseURL: https://fra.be.harmonic.gg
  tags:
  - Solana
  - MEV
  - Bundles
  - gRPC
  properties:
  - type: Protobuf
    url: grpc/harmonic-gg-searcher-searcher.proto
  - type: Protobuf
    url: grpc/harmonic-gg-searcher-auth.proto
  - type: Protobuf
    url: grpc/harmonic-gg-searcher-bundle.proto
  - type: Authentication
    url: authentication/harmonic-gg-authentication.yml
  - type: ErrorCatalog
    url: errors/harmonic-gg-error-codes.yml
- name: Harmonic Validator API (gRPC)
  description: >-
    gRPC services the Harmonic validator clients (Salsa/Samba) use to bind to a block
    builder: subscribe to packet and bundle streams, set the scheduling strategy,
    discover block engine endpoints, report leader windows, and proxy TPU traffic via
    the relayer.
  humanURL: https://docs.harmonic.gg/run-a-validator/endpoints
  baseURL: https://fra.auction.harmonic.gg
  tags:
  - Solana
  - Validator
  - Block Building
  - gRPC
  properties:
  - type: Protobuf
    url: grpc/harmonic-gg-validator-block_engine.proto
  - type: Protobuf
    url: grpc/harmonic-gg-validator-relayer.proto
  - type: Protobuf
    url: grpc/harmonic-gg-validator-auth.proto
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://harmonic.gg
- type: DeveloperPortal
  url: https://docs.harmonic.gg
- type: Documentation
  url: https://docs.harmonic.gg
- type: APIReference
  url: https://docs.harmonic.gg/searchers/harmonic-bundles
- type: GettingStarted
  url: https://docs.harmonic.gg/run-a-validator/setup
- type: Support
  url: https://discord.com/invite/23GfZkkyAG
- type: GitHubOrganization
  url: https://github.com/harmonic
- type: SourceCode
  url: https://github.com/harmonic/searcher-protos
- type: SignUp
  url: https://form.typeform.com/to/UlJMfbPH
- type: TermsOfService
  url: https://harmonic.gg/terms-and-conditions
- type: Protobuf
  name: Searcher gRPC protos
  url: grpc/harmonic-gg-searcher-searcher.proto
- type: Protobuf
  name: Validator gRPC protos
  url: grpc/harmonic-gg-validator-block_engine.proto
- type: LLMsTxt
  url: llms/harmonic-gg-llms.txt
- type: Authentication
  url: authentication/harmonic-gg-authentication.yml
- type: Sandbox
  url: sandbox/harmonic-gg-sandbox.yml
- type: Conventions
  url: conventions/harmonic-gg-conventions.yml
- type: Conformance
  url: conformance/harmonic-gg-conformance.yml
- type: ErrorCatalog
  url: errors/harmonic-gg-error-codes.yml
- type: Lifecycle
  url: lifecycle/harmonic-gg-lifecycle.yml
- type: DataModel
  url: data-model/harmonic-gg-data-model.yml
- type: MCPServer
  url: mcp/harmonic-gg-mcp.yml
- type: AgentSkill
  url: skills/_index.yml
- type: Packages
  url: packages/harmonic-gg-packages.yml
- type: DomainSecurity
  url: security/harmonic-gg-domain-security.yml
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence