> ## 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.
# simulateBundle
> Simulate a JITO bundle without executing it on the blockchain.
## Request Parameters
First configuration object. Contains the encoded transactions for the simulation.
Array of encoded, serialized transactions for simulation. The encoding is determined by the `transactionEncoding` field (base-64 by default).
Second configuration object. Optional.
Specifies which accounts to capture during simulation.
This captures the account states *before* the transaction is executed.
An array element at an index configures the transaction that is at the same index in the bundle.
For each transaction in the bundle:
* Pass `null` if you do not want any account state to be returned.
* Or, provide an object describing which accounts to return.
The array length must be equal to the number of transactions in the bundle.
Specifies which accounts to capture during simulation.
This captures the account states *after* the transaction is executed.
An array element at an index configures the transaction that is at the same index in the bundle.
For each transaction in the bundle:
* Pass `null` if you do not want any account state to be returned.
* Or, provide an object describing which accounts to return.
The array length must be equal to the number of transactions in the bundle.
The transaction encoding used in `encodedTransactions`.
* `base64`
* `base58`
Specified which bank to run the simulation against. Can be the tip, a slot, or a commitment level.
Whether to skip signature verification before simulation.
Whether to replace the simulated transaction's recent blockhash with the latest blockhash.
## OpenAPI
````yaml openapi/rpc-http/simulateBundle.yaml POST /
openapi: 3.1.0
info:
title: Solana RPC API
version: 1.0.0
description: >-
JITO Bundle Simulation API for testing and validating bundle execution
before submission to the Solana network via JITO validators.
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: simulateBundle
description: >
Simulate a JITO bundle without executing it on the blockchain. This
method allows developers
to test bundle execution, verify transaction behavior within bundles,
estimate compute unit
consumption, detect errors, and preview account state changes before and
after bundle execution.
Exclusively available for JITO-Solana validators and essential for MEV
strategy development
and bundle optimization.
operationId: simulateBundle
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
jsonrpc:
type: string
enum:
- '2.0'
description: The JSON-RPC protocol version.
example: '2.0'
default: '2.0'
id:
type: string
description: A unique identifier for the request.
example: '1'
default: '1'
method:
type: string
enum:
- simulateBundle
description: The name of the RPC method to invoke.
example: simulateBundle
default: simulateBundle
params:
type: array
description: Parameters for simulating a JITO bundle.
items:
type: object
description: Bundle simulation configuration object.
required:
- params[0]
properties:
params[0]:
type: object
description: >-
First configuration object. Contains the encoded
transactions for the simulation.
properties:
encodedTransactions:
type: array
description: >-
Array of encoded, serialized transactions for
simulation. The encoding is determined by the
`transactionEncoding` field (base-64 by default).
items:
type: string
description: Encoded serialized transaction.
example: >-
5rqF8aHfs9JyEtKTvND6z8RgBtYxQwZLndS1kzHxV7D3kWm9VoYRzFtsP3qra5bM8rGhCv82LYo8fZpQoyQmtN1D9vxG2uEsMhV7jB4KdADRgxMXn5kRJzLZPt2LrPSmcUhfEmeQa7XrKeR9FHdKcXxZ1Hdq68oBr2AaPpTMuL85KDCt
params[1]:
type: object
description: Second configuration object. Optional.
required:
- preExecutionAccountsConfigs
- postExecutionAccountsConfigs
properties:
preExecutionAccountsConfigs:
type: array
description: >
Specifies which accounts to capture during
simulation.
This captures the account states *before* the
transaction is executed.
An array element at an index configures the
transaction that is at the same index in the
bundle.
For each transaction in the bundle:
- Pass `null` if you do not want any account state to be returned.
- Or, provide an object describing which accounts to return.
The array length must be equal to the number of
transactions in the bundle.
items:
type:
- object
- 'null'
required:
- addresses
properties:
addresses:
type: array
description: >-
List of base-58 encoded account addresses
whose state will be captured.
items:
type: string
description: base-58 encoded account address.
example: >-
TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA
encoding:
type: string
description: >
The encoding in which the captured account
data will be returned.
default: base64
enum:
- binary
- base58
- base64
- jsonParsed
- base64+zstd
example: base64
postExecutionAccountsConfigs:
type: array
description: >
Specifies which accounts to capture during
simulation.
This captures the account states *after* the
transaction is executed.
An array element at an index configures the
transaction that is at the same index in the
bundle.
For each transaction in the bundle:
- Pass `null` if you do not want any account state to be returned.
- Or, provide an object describing which accounts to return.
The array length must be equal to the number of
transactions in the bundle.
items:
type:
- object
- 'null'
required:
- addresses
properties:
addresses:
type: array
description: >-
List of base-58 encoded account addresses
whose state will be captured.
items:
type: string
description: base-58 encoded account address.
example: >-
TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA
encoding:
type: string
description: >
The encoding in which the captured account
data will be returned.
default: base64
enum:
- binary
- base58
- base64
- jsonParsed
- base64+zstd
example: base64
transactionEncoding:
type: string
description: >-
The transaction encoding used in
`encodedTransactions`.
enum:
- base64
- base58
default: base64
simulationBank:
description: >
Specified which bank to run the simulation
against. Can be the tip, a slot, or a commitment
level.
oneOf:
- type: string
description: >-
Use the RPC's highest slot's bank, i.e. the
working bank.
example: tip
- type: object
description: >-
Simulate on the provided slot's bank (may not
be available).
properties:
slot:
type: integer
example: 373976835
required:
- slot
- type: object
description: Define a commitment level to simulate against.
properties:
commitment:
type: object
properties:
commitment:
type: string
enum:
- processed
- confirmed
- finalized
description: Commitment level to simulate against.
example: processed
required:
- commitment
required:
- commitment
skipSigVerify:
type: boolean
description: >-
Whether to skip signature verification before
simulation.
default: false
replaceRecentBlockhash:
type: boolean
description: >-
Whether to replace the simulated transaction's
recent blockhash with the latest blockhash.
default: false
example:
jsonrpc: '2.0'
id: '1'
method: simulateBundle
params:
- encodedTransactions:
- >-
5rqF8aHfs9JyEtKTvND6z8RgBtYxQwZLndS1kzHxV7D3kWm9VoYRzFtsP3qra5bM8rGhC
v82LYo8fZpQoyQmtN1D9vxG2uEsMhV7jB4KdADRgxMXn5kRJzLZPt2LrPSmcUhfEmeQa7X
rKeR9FHdKcXxZ1Hdq68oBr2AaPpTMuL85KDCt
- >-
5rqF8aHfs9JyEtKTvND6z8RgBtYxQwZLndS1kzHxV7D3kWm9VoYRzFtsP3qra5bM8rGhC
v82LYo8fZpQoyQmtN1D9vxG2uEsMhV7jB4KdADRgxMXn5kRJzLZPt2LrPSmcUhfEmeQa7X
rKeR9FHdKcXxZ1Hdq68oBr2AaPpTMuL85KDCt
- preExecutionAccountsConfigs:
- addresses:
- TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA
encoding: base64
- null
postExecutionAccountsConfigs:
- addresses:
- TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA
encoding: base64
- null
skipSigVerify: true
simulationBank:
commitment:
commitment: processed
transactionEncoding: base64
replaceRecentBlockhash: false
responses:
'200':
description: Successfully simulated the bundle.
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: Result of the simulated bundle.
properties:
context:
type: object
description: Context of the simulation response.
properties:
apiVersion:
type: string
description: The API version.
example: 2.30.10
slot:
type: integer
description: Slot in which the data was processed.
example: 373999891
value:
type: object
description: Details of the simulated bundle result.
properties:
summary:
description: >
Summary of the bundle simulation result.
If the simulation succeeded, this is set to
`"succeeded"`.
If the simulation failed, this is set to an object
with a single field `failed` that contains details
on that failure.
oneOf:
- type: string
example: succeeded
- type: object
required:
- failed
properties:
failed:
type: object
required:
- error
properties:
error:
description: >-
Value containing details on the error.
Structure may vary.
tx_signature:
type: string
description: >-
Signature of the failed transaction in
base58. May be `null` if not applicable.
transactionResults:
type: array
description: >-
Array of results for each transaction in the
bundle. Can be empty if there was an error.
items:
type: object
properties:
err:
type:
- object
- 'null'
description: >-
Error if the transaction failed, `null` if
successful.
logs:
type:
- array
- 'null'
description: >-
Array of log messages from transaction
execution.
items:
type: string
example: >-
Program
4Nd1mFvxhG1DQMLUKhMzrZ7yG1UrjC9xXH6kvvZtcg9R
invoke [1]
preExecutionAccounts:
type:
- array
- 'null'
description: >-
Account states before the transaction's
execution.
items:
type: object
properties:
data:
type: string
description: Data associated with the account.
executable:
type: boolean
description: Whether the account contains a program.
example: false
lamports:
type: integer
description: >-
Number of lamports assigned to this
account.
example: 1500000000
owner:
type: string
description: >-
Address of the program that owns this
account.
example: >-
4Nd1mFvxhG1DQMLUKhMzrZ7yG1UrjC9xXH6kvvZtcg9R
rentEpoch:
type: integer
description: >-
Epoch at which this account will next
owe rent.
example: 324
space:
type: integer
description: The data size of the account.
example: 1024
postExecutionAccounts:
type:
- array
- 'null'
description: >-
Account states after the transaction's
execution.
items:
type: object
properties:
data:
type: string
description: Data associated with the account.
executable:
type: boolean
description: Whether the account contains a program.
example: false
lamports:
type: integer
description: >-
Number of lamports assigned to this
account.
example: 1500000000
owner:
type: string
description: >-
Address of the program that owns this
account.
example: >-
4Nd1mFvxhG1DQMLUKhMzrZ7yG1UrjC9xXH6kvvZtcg9R
rentEpoch:
type: integer
description: >-
Epoch at which this account will next
owe rent.
example: 324
space:
type: integer
description: The data size of the account.
example: 1024
unitsConsumed:
type: integer
description: >-
Number of compute budget units consumed
during processing.
example: 200000
returnData:
type:
- object
- 'null'
description: >-
Most recent return data generated by an
instruction.
properties:
programId:
type: string
description: Program that generated the return data.
example: >-
Fx9Hp1gLzYj6Ryc4GaVoq2v6t4NxWg3GT1kP7quzZbVQ
data:
type: string
description: >-
Return data as base-64 encoded binary
data.
example: >-
AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAASjD8=
example:
jsonrpc: '2.0'
id: '1'
result:
context:
apiVersion: 2.30.10
slot: 373999891
value:
summary: succeeded
transactionResults:
- err: null
logs:
- >-
Program ComputeBudget111111111111111111111111111111
invoke [1]
- >-
Program ComputeBudget111111111111111111111111111111
success
- >-
Program ComputeBudget111111111111111111111111111111
invoke [1]
- >-
Program ComputeBudget111111111111111111111111111111
success
- Program 11111111111111111111111111111111 invoke [1]
- Program 11111111111111111111111111111111 success
preExecutionAccounts:
- data:
- ''
- base64
executable: true
lamports: 5299606121
owner: BPFLoader2111111111111111111111111111111111
rentEpoch: 324
space: 134080
postExecutionAccounts:
- data:
- ''
- base64
executable: true
lamports: 5299606121
owner: BPFLoader2111111111111111111111111111111111
rentEpoch: 324
space: 134080
returnData:
programId: Fx9Hp1gLzYj6Ryc4GaVoq2v6t4NxWg3GT1kP7quzZbVQ
data: AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAASjD8=
unitsConsumed: 450
- err: null
logs:
- >-
Program ComputeBudget111111111111111111111111111111
invoke [1]
- >-
Program ComputeBudget111111111111111111111111111111
success
- >-
Program ComputeBudget111111111111111111111111111111
invoke [1]
- >-
Program ComputeBudget111111111111111111111111111111
success
- Program 11111111111111111111111111111111 invoke [1]
- Program 11111111111111111111111111111111 success
postExecutionAccounts: null
preExecutionAccounts: null
returnData: null
unitsConsumed: 450
'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).
````