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API Reference

Relayer/TPU is a push service: Blockspace's relayer connects to a gRPC endpoint you operate and streams pending TPU transactions into it. The architecture mirrors Jito Relayer ↔ Block Engine.

Direction of flow​

Everstake validator TPU
        │
        ▼
Blockspace relayer  ──gRPC──►  Your Block Engine endpoint

You define the gRPC schema (recommended: mirror jito-labs/block_engine_simple). Blockspace connects as a client.

What you provide​

In the dashboard → Relayer/TPU → Subscribe:

  • Block Engine gRPC URL — the endpoint Blockspace's relayer connects to.
  • Auth URL — optional, only if your auth service is split out from the Block Engine itself.

Examples:

https://be.example.com/                                     # combined: BE + auth
https://be.example.com/   https://auth.be.example.com/      # split
https://be.example.net/
https://203.0.113.3:10000
http://203.0.113.4:10001

Both HTTPS and HTTP (with explicit port) are accepted.

Allowlist key​

If your endpoint operates with an allowlist, allow the Blockspace relayer key:

EsSaJ9ZZd59QAQYF38nnXGEDFpJSdRVhzpoN1rdNvJRG

This is the Solana identity our relayer uses to authenticate against Block Engines. Configure your auth service to recognize it as authorized.

Reference implementation​

There's no public turn-key Block Engine that runs out of the box. The minimum viable example to study and adapt is:

jito-labs/block_engine_simple — bare gRPC server that accepts a stream of pending transactions.

You typically:

  1. Fork or clone that repo as a starting point.
  2. Implement your business logic on top (filter, fanout, OFA auction, JIT detection — whatever your strategy needs).
  3. Deploy and harden the auth layer.
  4. Provide the URL(s) to Blockspace and allowlist our relayer key.

Coverage​

Blockspace can only forward what its validators receive on TPU. The signal is:

  • Richer than any single validator — you see traffic addressed to multiple validators in our network.
  • Incomplete, by nature — txs sent only to non-Blockspace-network validators don't appear.
  • Coverage scales with how many validators opt in via Searcher Connection.

Operational notes​

  • Connection lifecycle — Blockspace's relayer connects on demand and reconnects automatically, so your endpoint should stay available 24/7.
  • Backpressure — your endpoint must keep up with TPU rate. Fall behind on processing and you'll drop messages.
  • Scaling — horizontal scaling is on you. Blockspace doesn't fan out across multiple of your endpoints — provide one URL.

Status​

Connection status is surfaced in the dashboard. If our relayer can't reach your endpoint or auth fails, you'll see it there with the reason.