Developer docs

Flashbots & BlockRazor-style relay — Robinhood Chain

HashDude is an open Flashbots-compatible private bundle relay and BlockRazor-style block builder for Robinhood Chain (chain ID 4663). No API key — copy a URL, sign locally, submit bundles via eth_sendBundle or REST.

Copy & use these URLs

Flashbots relay For eth_sendBundle — bots & searchers

…

REST API base For /tx/build and /tx/submit

…

Config Chain ID, min tip, limits (GET)

…

Chain4663

Min tip…

Tip address…

AccessNo API key

How to use (REST)

Copy the REST API base URL above
POST {api}/tx/build with your transaction — tip is added automatically
Sign the returned unsigned.txs in your wallet or bot (tip tx first)
POST {api}/tx/submit with rawTransactions: ["0x...", ...]

Loading…

How to use (Flashbots bot)

Copy the Flashbots relay URL above
Set your bundle provider relay to that URL (instead of relay.flashbots.net)
Sign your bundle txs locally (include a tip tx to the builder address)
Call eth_sendBundle on the HashDude relay URL

Loading…

Rules

Open access — no API key required
Tip required — min 0.00001 ETH per bundle (auto-added on /v1/tx/build)
Max 10 txs per bundle (1 tip + 9 user transactions)
Same block — block-synced parallel burst; split bundles rejected

REST API

Method	Path	Description
GET	`/v1/health`	Health check
GET	`/v1/config`	Chain info, tip rules, limits
POST	`/v1/tx/build`	Build tx + auto tip
POST	`/v1/tx/simulate`	Simulate before sign
POST	`/v1/tx/submit`	Submit signed bundle
POST	`/v1/bundle/build`	Multi-tx bundles (swaps)
POST	`/v1/bundle/submit`	Submit advanced bundle

Flashbots relay (curl)

Drop-in for searchers — point @flashbots/ethers-provider-bundle at HashDude /relay.

Loading…

Methods: eth_sendBundle, eth_callBundle, eth_cancelBundle, mev_sendBundle, mev_simBundle

Swap / launch bundle

Loading…

Multi-signer (9 wallets + tip)

Each wallet signs its own tx. Submit all signed hex strings in one /v1/tx/submit or eth_sendBundle call.

Loading…

Errors

HTTP / code	Meaning
`402 TIP_REQUIRED`	Tip missing or below minimum
`409 BUNDLE_INCLUSION_FAILED`	Bundle split across blocks
`400`	Invalid params or simulation failed