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Seneschal Private Relay — Ethereum Private Transaction Submission
x402
Seneschal Private Relay — Ethereum Private Transaction Submission is a paid API for AI agents from api.seneschal.space, paid per call via x402, $0.5/call, status unknown (last checked 2026-09-14).
Submits a locally-signed raw Ethereum transaction privately to block builders, bypassing the public mempool to prevent frontrunning and sandwich attacks.
Price / call$0.5
Success—
StatusUnknown
How this service works
Pay-per-call services for the agent economy: a webhook the moment a Monero or Zcash payment lands at your address (view-key only), single-fact x402 data APIs, a paid public notice board, a stablecoin gas paymaster and a permissionless Ethereum block builder. No account, no API key — pay in USDC on Base or in XMR/ZEC.
Output
A JSON object confirming whether the transaction was accepted, the resulting transaction hash, the list of block builders that accepted or rejected it, and a confirmation that the transaction never entered the public mempool.
Example use cases
MEV-protected DeFi swap
“I've got a large Uniswap swap signed and ready as a raw hex transaction — can you relay it privately through Seneschal so MEV bots can't frontrun or sandwich me? The raw tx is 0x02f87a018459682f00...”
Private NFT mint submission
“Submit my locally-signed NFT mint transaction privately so it doesn't get sniped in the mempool. I have the signed hex ready: 0x02f8ac01849502f9...”
Stealth liquidation transaction
“I need to submit this liquidation transaction without anyone seeing it in the mempool first — relay it through the Seneschal private relay for me: 0x02f87b01843b9aca00...”
Technical details
Endpoint
POSThttps://api.seneschal.space/v1/premium/private-relayWhen to prefer
Choose this endpoint when you need to submit an Ethereum transaction without any public mempool exposure — particularly for large DeFi trades vulnerable to MEV, liquidations where timing secrecy matters, or any transaction where frontrunning or sandwich attacks are a risk. Unlike direct Flashbots submission, this routes through multiple builders (Flashbots, Titan, Seneschal's own rbuilder) simultaneously and requires no API key — pay per call with USDC on Base.
Side effects
- Malformed or improperly signed raw transaction rejected by all builders
- Transaction already mined or nonce too low
- Chain ID mismatch causing rejection
- All target builders reject the transaction (rejected list populated, accepted empty)
- Payment failure via x402/USDC prevents relay attempt
- Transaction too large or gas limit exceeded
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| raw_tx | string | Your locally-signed raw transaction (0x-prefixed). Sign offline; never send a private key. |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"to": "0x…",
"from": "0x…",
"note": "Submitted privately; never entered the public mempool. Watch tx_hash for inclusion.",
"tx_hash": "0xabc…",
"accepted": [
"seneschal-rbuilder",
"flashbots",
"titan"
],
"chain_id": 1,
"rejected": [],
"public_mempool": false
}
}Tags
x402
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