Block-builder direct RPC — Ethereum REST API

Send a bundle straight to a named Ethereum block builder over JSON-RPC, bypassing the public mempool.

POSThttps://triport.io/rpc/eth-builder/beaverbuild

Network: Ethereum
Scope: mev.builder_direct feature (Scale tier)
Auth: x-token: $TRIPORT_API_KEY (or Authorization: Bearer)
Rate limit: Scale tier only; RPS-per-tier with burst (no daily cap)

Endpoint and plans: Ethereum RPC endpoint.

Request

cURLJavaScriptPython

curl https://triport.io/rpc/eth-builder/beaverbuild \
  -H "Authorization: Bearer $TRIPORT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_sendBundle",
    "params": [{
      "txs": ["0x02f8..."],
      "blockNumber": "0x1310f30"
    }]
  }'

const res = await fetch("https://triport.io/rpc/eth-builder/beaverbuild", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_sendBundle",
    "params": [
      {
        "txs": [
          "0x02f8..."
        ],
        "blockNumber": "0x1310f30"
      }
    ]
  }),
});
const data = await res.json();
console.log(data);

import os


import requests


resp = requests.post(
    "https://triport.io/rpc/eth-builder/beaverbuild",
    headers={
        "Authorization": f"Bearer {os.environ['TRIPORT_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "jsonrpc": "2.0",
        "id": 1,
        "method": "eth_sendBundle",
        "params": [
            {
                "txs": [
                    "0x02f8...",
                ],
                "blockNumber": "0x1310f30",
            },
        ],
    },
)
data = resp.json()
print(data)

Response

JSON

Example

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "bundleHash": "0x2e4b4534a1c9f0d8b6e7a3f5c0d9e8b7a6f5e4d3c2b1a09f8e7d6c5b4a3928170"
  }
}

/rpc/eth-builder/ is a direct, write-only JSON-RPC channel to the block-builder pool. Each request targets one builder by appending its short id to the path (/rpc/eth-builder/beaverbuild), and the body is forwarded verbatim to that builder's RPC endpoint. Use it when you need builder-specific bundle submission — sending or simulating a bundle against a single builder rather than fanning out through the private RPC forwarder.

The endpoint is method-whitelisted: only the bundle-dispatch methods eth_sendBundle, eth_callBundle, and mev_sendBundle are accepted. Any read method (eth_getBalance, eth_call, etc.) is rejected with method_not_allowed_on_builder — this is a write canal, not a general-purpose RPC. Both single requests and JSON-RPC batch arrays are supported; in a batch, every element must use an allowed method or the whole request is rejected.

Access is tier-gated to the Scale plan via the mev.builder_direct feature. Requests on any lower plan return 403 tier_locked. The request body is capped at 2 MiB, and the upstream call uses a configurable timeout (default 10 s) — a slow or unreachable builder surfaces as a 502.

Parameters

Path parameters

builder_idstringrequired

Short id of the target block builder (e.g. beaverbuild, titanbuilder, rsync). Must be a single path segment — a trailing slash, an empty id, or extra path segments return 404 invalid_path. Unknown ids return 404 builder_not_found.

Request bodyobject

jsonrpcstringrequired

JSON-RPC version, "2.0".

idnumber | stringrequired

Client request id, echoed in the response.

methodstringrequired

One of eth_sendBundle, eth_callBundle, mev_sendBundle.

paramsarrayrequired

Method-specific parameters (e.g. the bundle object). Forwarded unchanged to the builder.

Response

jsonrpcstring

JSON-RPC version, "2.0".

idnumber | string

Echoes the request id.

resultobject

Builder-defined result. For eth_sendBundle / mev_sendBundle this typically contains the accepted bundleHash; for eth_callBundle it is the simulation result.

errorobject

Present instead of result when the builder rejects the bundle (standard JSON-RPC error object).

Errors

Errors raised by the proxy use the shared envelope {"error": "<code>", "code": <http_status>}. See errors.md for the full envelope.

Code	Meaning	When it happens
`400`	`body_read_error`	The request body could not be read.
`401`	—	Missing or invalid `Authorization` bearer key.
`403`	`tier_locked`	The API key's plan does not include `mev.builder_direct` (anything below Scale).
`404`	`invalid_path`	No builder id segment, an empty id, or extra path segments after the id.
`404`	`builder_not_found`	The builder id is not present in the configured builder pool.
`405`	`method_not_allowed`	The HTTP method is not `POST`.
`405`	`method_not_allowed_on_builder`	A non-whitelisted JSON-RPC method was used (only `eth_sendBundle` / `eth_callBundle` / `mev_sendBundle` are allowed).
`429`	—	Per-tier RPS limit exceeded (burst-limited; there is no daily quota).
`502`	`builder_unavailable`	The upstream builder did not respond (connection failure or timeout).
`502`	`builder_read_error`	The builder responded but its body could not be read.

Examples

JavaScript (fetch)

JavaScript

const res = await fetch(
  "https://triport.io/rpc/eth-builder/beaverbuild",
  {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.TRIPORT_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      jsonrpc: "2.0",
      id: 1,
      method: "eth_sendBundle",
      params: [{ txs: ["0x02f8..."], blockNumber: "0x1310f30" }],
    }),
  },
);
const data = await res.json();
console.log(data.result?.bundleHash);

Notes

Write-only by design. Only eth_sendBundle, eth_callBundle, and mev_sendBundle reach the builder. Use eth_callBundle to simulate a bundle before submitting it with eth_sendBundle.
One builder per call. The path selects a single builder. To dispatch to multiple builders, send to each id, or use the private RPC forwarder which spreads a bundle across the configured set.
Batch atomicity is per-method only. A batch array is accepted as a whole; if any element uses a disallowed method the entire request returns method_not_allowed_on_builder. There is no partial acceptance.
Body limit: 2 MiB. Larger payloads are truncated at read and will fail validation.
Timeout: the upstream call uses a configurable timeout (default 10 s); exceeding it returns 502 builder_unavailable.
Related: Private RPC forwarder.