How to send orderflow

Orderflow sent to Flashbots Protect, Flashbots Bundle Relay and MEV-Share is automatically shared with BuilderNet. Advanced users can send orderflow directly to BuilderNet nodes.

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note

The instructions in this document are intended for advanced technical users. As a regular user, you can simply use Flashbots Protect to transact securely through BuilderNet and get refunds for your transactions.

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Sending orderflow to BuilderNet directly

The global endpoint rpc.buildernet.org automatically routes requests to the closest available BuilderNet node. To target a specific region (e.g. US or EU), use the corresponding regional endpoint.

Submitted orderflow is propagated to all other nodes.

For best performance, reuse a single long-lived connection instead of opening a new one per request — this avoids repeating the TCP and TLS handshakes on every submission. Prefer HTTP/2, which multiplexes many requests over one connection. On HTTP/1.1, keep the connection open with the Connection: keep-alive header and reuse it across requests.

BuilderNet endpoints

Region	Endpoint	Orderflow Port
Global	https://rpc.buildernet.org	443
United States	https://direct-us.buildernet.org	443
Europe	https://direct-eu.buildernet.org	443
Asia Pacific	https://direct-ap.buildernet.org	443

Supported API methods

1. eth_sendBundle
2. eth_sendRawTransaction
3. Priority updates — quote updates from propAMM market makers (WebSocket, API key required)
4. Quote stream — read-only WebSocket with the pending propAMM quote state (no key required)

See also the API reference for more details on the API methods.

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Rate limits

The following rate limits apply per client when sending requests to the BuilderNet RPC endpoints:

• New TCP connections per second: 10
• Concurrent TCP connections: 10
• Bandwidth in: 600 MB/min (~10 MB/s)
• HTTP request rate: 1000 per 10s (~100/s)

If you need increased limits, reach out to us in the Telegram group: t.me/buildernet_general.

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Example curl request

This request sends a signed transaction to BuilderNet:

curl https://rpc.buildernet.org \
    --header 'Content-Type: application/json' \
    --header 'X-Flashbots-Signature: <public key address>:<signature>' \
    --data '{
        "id": 1,
        "jsonrpc": "2.0",
        "method": "eth_sendBundle",
        "params": [{
            "blockNumber": "0x1361bd3",
            "txs": [
                "0x100000...",
                "0x200000..."
            ]
        }]
    }'

See this example Golang code for sending a transaction with a signed request.

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Request authentication

JSON-RPC requests (eth_sendBundle, eth_sendRawTransaction) need a X-Flashbots-Signature header. The signature is calculated by taking the EIP-191 hash of the json body encoded as UTF-8 bytes. Any valid ECDSA secp256k1 key (i.e. any Ethereum key) can be used to sign the payload. The address associated with this key will be used for Redistribution.

For more details and examples on signing the payload, see the documentation here.

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Example Golang code

See this example Golang code for sending a signed transaction to a builder node.

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Join the discussion in the Flashbots forum!