Overview

POST /v1/tx is a dedicated async transaction submission endpoint. Transactions are accepted and return HTTP 202 Accepted immediately, then forwarded to Robinhood Chain in the background with built-in retry logic.

This endpoint is designed for scenarios requiring minimal submission latency, with client-perceived latency < 5 ms.

Comparison with /v1/rpc

Feature	/v1/rpc	/v1/tx
Mode	Synchronous (waits for on-chain response)	Asynchronous (queued, returns 202)
Methods	All JSON-RPC methods	Transaction methods only
Response	On-chain response	Submission confirmation
Content-Type	application/json	application/json or text/plain
Quota	Query quota	Transaction quota (independent)

Request Format

POST /v1/tx
Content-Type: application/json or text/plain
X-User-ID: <your-api-key>

Examples

JSON-RPC Format

curl -X POST https://robinhood-ohio.flashblock.trade/v1/tx \
  -H "Content-Type: application/json" \
  -H "X-User-ID: <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_sendRawTransaction",
    "params": ["0xf86c0a8502540be400825208943535..."],
    "id": 1
  }'

Response (202 Accepted):

{
  "code": "accepted",
  "message": "transaction queued for submission",
  "request_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890"
}

Raw Hex Format

Submit a signed raw transaction hex string directly, without wrapping it in JSON-RPC:

curl -X POST https://robinhood-ohio.flashblock.trade/v1/tx \
  -H "Content-Type: text/plain" \
  -H "X-User-ID: <your-api-key>" \
  -d '0xf86c0a8502540be400825208943535...'

Response (202 Accepted):

{
  "code": "accepted",
  "message": "transaction queued for submission",
  "request_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890"
}

Supported Content Types

Content-Type	Behavior
application/json	Parsed as a standard JSON-RPC request
text/plain	Treated as raw transaction hex, auto-wrapped as eth_sendRawTransaction
application/octet-stream	Same as text/plain

Supported Methods

This endpoint only accepts transaction methods:

• eth_sendRawTransaction
• eth_sendTransaction

Sending query methods (e.g., eth_chainId, eth_getBalance) will return a 400 tx_method_required error. Use /v1/rpc for queries.

Independent Quota

The transaction endpoint /v1/tx and the query endpoint /v1/rpc use completely independent quotas:

• When query quota is exhausted, transaction submission remains available
• When transaction quota is exhausted, query requests remain available
• Both quotas are determined by your plan tier

See Pricing and Plans for details.