# Harmonic GG

**Canonical:** https://apis.io/providers/harmonic-gg/  
**Website:** https://harmonic.gg  
**APIs profiled:** 2

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.

## Kin Score — 30.4 / 100 (thin)

Scored 2026-08-19 under rubric 0.12.0. Trend: flat (+4.9 from 25.5).

| Facet | Score |
|---|---|
| Discoverability | 75.9 |
| Contract Quality | 28.2 |
| Governance | 4.5 |
| Contract Governance | 4.5 |
| Operational Transparency | 2.6 |
| Developer Ergonomics | 63.7 |
| Commercial Clarity | 10.5 |
| Access Clarity | 10.5 |

## Agent readiness — 28.4 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | documented |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | derived |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## APIs (2)

- **Harmonic Searcher API (gRPC)** — gRPC bundle-submission interface for searchers. Authenticate with a Solana keypair (challenge-response to Bearer tokens), then submit atomic transaction bundles with revert prot...
- **Harmonic Validator API (gRPC)** — 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 en...

## MCP servers (1)

- **harmonic-gg-mcp.yml**

## Security (2)

- **Harmonic Gg Authentication** — challenge-response/bearer · 2 schemes
- **Harmonic Gg Domain Security** — TLSv1.3 · HSTS

## Tags

Company, Blockchain, Solana, Block Building, MEV, Validator, Searcher, Infrastructure, gRPC, DeFi

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/harmonic-gg/). Scores are computed from the provider's own public artifacts under a published rubric.