Skip to main content
POST
/
fast
sendTransaction
curl --request POST \
  --url https://sender.helius-rpc.com/fast \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "sendTransaction",
  "params": [
    "Ab/WBgJxCprwWlK2fCxSwm9KrWlJQW8TdnYqXMvg5KropeLqHaa5yJeoWUb+LsGi6zlfs1Z/jA/RgJW++tBhPAKAAQACBGuePYZrXq9Jj+DwkquiMvsrNU5rlcAbmRfuAYui/CwAQr437DqfrFoSt1BSgM/2/0Iqja1QMefnu1hTYX96AA0DBkZv5SEXMv/srbpyw5vnvIzlu8X3EmssQ5s6QAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAhWHa4WfUT12o+cyi2WGwfBvngyurXf5VQd4Ukn+5ZSIDAgAFAqCGAQACAAkDQA0DAAAAAAADAgABDAIAAABAQg8AAAAAAAA=",
    {
      "encoding": "base64",
      "skipPreflight": true,
      "maxRetries": 0
    }
  ]
}
'
{
  "jsonrpc": "2.0",
  "id": "1",
  "result": "4qTLpN1sBrp5SzZUKfrSH2897FmxA7AB4EbN4ccgSgEjG9RG2686pSKWhEbz65q4bvaRsdpKRJKZ3dkdGZA78u5s"
}

​
Request Parameters

​
swqos_only
boolean
default:"false"
When true, routes exclusively through SWQOS infrastructure, but has a lower minimal tip requirement.
​
transaction
string
required
The transaction encoded in base64.
​
encoding
string
Data encoding format used for the Solana transaction payload.
  • base58
  • base64
​
skipPreflight
boolean
required
When true, bypasses Solana’s preflight transaction validation for faster submission. Must be set to true for Sender.
​
maxRetries
number
Maximum number of automatic retry attempts. Should be set to 0.

Query Parameters

​
api-key
string

Standard users do not require an API key. Only users with custom TPS limits need to provide an API key.

​
swqos_only
boolean
default:false

When true, routes exclusively through SWQOS infrastructure, but has a lower minimal tip requirement.

Body

application/json
​
jsonrpc
enum<string>
default:2.0

The JSON-RPC protocol version.

Available options:
2.0
Example:

"2.0"

​
id
string
default:1

A unique identifier for the request.

Example:

"1"

​
method
enum<string>
default:sendTransaction

The name of the RPC method to invoke.

Available options:
sendTransaction
Example:

"sendTransaction"

​
params
(string | object)[]

Parameters for sending a transaction via Sender.

The transaction encoded in base64.

Response

Transaction submitted successfully. Since we're skipping preflight checks, a 200 response does not guarantee that the transaction is valid or that it will land onchain.

​
jsonrpc
enum<string>

The JSON-RPC protocol version.

Available options:
2.0
Example:

"2.0"

​
id
string

Identifier matching the request.

Example:

"1"

​
result
string

The transaction signature for tracking confirmation status.

Example:

"4qTLpN1sBrp5SzZUKfrSH2897FmxA7AB4EbN4ccgSgEjG9RG2686pSKWhEbz65q4bvaRsdpKRJKZ3dkdGZA78u5s"