> ## Documentation Index
> Fetch the complete documentation index at: https://www.helius.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# getLatestBlockhash
> Returns the latest Solana blockhash required for constructing fresh transactions. Blockhashes expire after ~150 slots — fetch one just before signing to maximize the inclusion window.
## Request Parameters
The commitment level for the request.
* `confirmed`
* `finalized`
* `processed`
The minimum slot that the request can be evaluated at.
## OpenAPI
````yaml openapi/rpc-http/getLatestBlockhash.yaml POST /
openapi: 3.1.0
info:
title: Solana RPC API
version: 1.0.0
description: >-
Essential Solana transaction preparation API for retrieving the latest valid
blockhash required for creating and signing blockchain transactions.
license:
name: Apache 2.0
url: https://www.apache.org/licenses/LICENSE-2.0.html
servers:
- url: https://mainnet.helius-rpc.com
description: Mainnet RPC endpoint
- url: https://devnet.helius-rpc.com
description: Devnet RPC endpoint
security: []
paths:
/:
post:
tags:
- RPC
summary: getLatestBlockhash
description: >
Retrieve the latest valid blockhash from the Solana blockchain,
essential for transaction creation.
This fundamental API provides the current blockhash and its validity
period, which are required
components when constructing any Solana transaction. The blockhash
serves as both a recent state
reference and a replay protection mechanism. Every transaction must
include a recent blockhash
to be considered valid by the network. Critical for wallet providers,
DApps, and any service
that submits transactions to the Solana blockchain.
operationId: getLatestBlockhash
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- jsonrpc
- id
- method
properties:
jsonrpc:
type: string
description: The JSON-RPC protocol version.
enum:
- '2.0'
example: '2.0'
default: '2.0'
id:
type: string
description: A unique identifier for the request.
example: '1'
default: '1'
method:
type: string
description: The name of the RPC method to invoke.
enum:
- getLatestBlockhash
example: getLatestBlockhash
default: getLatestBlockhash
params:
type: array
description: Optional configuration object for the request.
items:
type: object
properties:
commitment:
type: string
description: The commitment level for the request.
enum:
- confirmed
- finalized
- processed
example: processed
minContextSlot:
type: integer
description: The minimum slot that the request can be evaluated at.
example: 1000
responses:
'200':
description: Successfully retrieved the latest blockhash information.
content:
application/json:
schema:
type: object
properties:
jsonrpc:
type: string
description: The JSON-RPC protocol version.
enum:
- '2.0'
example: '2.0'
id:
type: string
description: Identifier matching the request.
example: '1'
result:
type: object
description: RpcResponse containing blockhash information.
properties:
context:
type: object
description: Context of the response.
properties:
slot:
type: integer
description: The slot at which the data was fetched.
example: 2792
value:
type: object
description: Blockhash and its validity details.
properties:
blockhash:
type: string
description: >-
The latest Solana blockhash encoded as a base-58
string, required for transaction creation.
example: EkSnNWid2cvwEVnVx9aBqawnmiCNiDgp3gUdkDPTKN1N
lastValidBlockHeight:
type: integer
description: >-
The last Solana block height at which this
blockhash will be accepted in transactions.
example: 3090
'400':
description: Bad Request - Invalid request parameters or malformed request.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32602
message: Invalid params
id: '1'
'401':
description: Unauthorized - Invalid or missing API key.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32001
message: Unauthorized
id: '1'
'429':
description: Too Many Requests - Rate limit exceeded.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32005
message: Too many requests
id: '1'
'500':
description: Internal Server Error - An error occurred on the server.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32603
message: Internal error
id: '1'
'503':
description: Service Unavailable - The service is temporarily unavailable.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32002
message: Service unavailable
id: '1'
'504':
description: Gateway Timeout - The request timed out.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
example:
jsonrpc: '2.0'
error:
code: -32003
message: Gateway timeout
id: '1'
security:
- ApiKeyQuery: []
components:
schemas:
ErrorResponse:
type: object
properties:
jsonrpc:
type: string
description: The JSON-RPC protocol version.
enum:
- '2.0'
example: '2.0'
error:
type: object
properties:
code:
type: integer
description: The error code.
example: -32602
message:
type: string
description: The error message.
data:
type: object
description: Additional data about the error.
id:
type: string
description: Identifier matching the request.
example: '1'
securitySchemes:
ApiKeyQuery:
type: apiKey
in: query
name: api-key
description: >-
Your Helius API key. You can get one for free in the
[dashboard](https://dashboard.helius.dev/api-keys).
````