# simulateTransaction

## simulateTransaction — Simulate a transaction

> Simulates sending a transaction to get the effects that would occur if the transaction was committed. The simulation runs against the current state of the blockchain and provides detailed information including logs, account changes, compute units consumed, and any errors that would occur during execution.\
> \*\*Parameters\*\*\
> \
> 0\. \`transaction\` (required) — Encoded transaction (signed or unsigned, depending on \`sigVerify\`).\
> 1\. \`config\` (optional) — Optional configuration object. Every field is optional; omit the entire object to use defaults.<br>

```json
{"openapi":"3.0.3","info":{"title":"Solana RPC: simulateTransaction","version":"1.0.0"},"tags":[{"name":"Transactions","description":"Solana RPC transactions method."}],"servers":[{"url":"https://public.rpc.solanavibestation.com","description":"Public endpoint (rate-limited, no auth)"},{"url":"https://lite.rpc.solanavibestation.com","description":"Lite tier"},{"url":"https://basic.rpc.solanavibestation.com","description":"Basic tier"},{"url":"https://ultra.rpc.solanavibestation.com","description":"Ultra tier"},{"url":"https://elite.rpc.solanavibestation.com","description":"Elite tier"},{"url":"https://epic.rpc.solanavibestation.com","description":"Epic tier"},{"url":"https://basic.swqos.solanavibestation.com","description":"Basic tier with Stake-Weighted QoS"},{"url":"https://ultra.swqos.solanavibestation.com","description":"Ultra tier with Stake-Weighted QoS"},{"url":"https://elite.swqos.solanavibestation.com","description":"Elite tier with Stake-Weighted QoS"}],"security":[{},{"AuthHeader":[]},{"URLParameter":[]}],"components":{"securitySchemes":{"AuthHeader":{"type":"apiKey","in":"header","name":"Authorization","description":"Pass `Authorization: <api-key>` on each request."},"URLParameter":{"type":"apiKey","in":"query","name":"api_key","description":"Pass `?api_key=<api-key>` on the URL."}},"schemas":{"Commitment":{"type":"string","enum":["processed","confirmed","finalized"],"default":"finalized","description":"How finalized a block is at query time:\n- `processed`: most recent block, may be skipped\n- `confirmed`: block confirmed by supermajority of cluster\n- `finalized`: block finalized by the cluster (>2/3 stake)"},"Encoding":{"type":"string","enum":["json","jsonParsed","base58","base64","base64+zstd"],"description":"Encoding for transaction or account data."},"JsonRpcEnvelope":{"type":"object","required":["jsonrpc","id"],"description":"Base envelope of every JSON-RPC 2.0 response.","properties":{"jsonrpc":{"type":"string","enum":["2.0"]},"id":{"oneOf":[{"type":"string"},{"type":"integer"}],"description":"Echoed request id."}}},"Context":{"type":"object","description":"RPC context block returned alongside most account-level results.","required":["slot"],"properties":{"slot":{"type":"integer","format":"int64"},"apiVersion":{"type":"string"}}},"AccountInfo":{"type":"object","description":"On-chain account state.","nullable":true,"required":["lamports","owner","executable","rentEpoch","data"],"properties":{"lamports":{"type":"integer","format":"int64","description":"Balance in lamports."},"owner":{"type":"string","description":"Base-58 program id that owns the account."},"executable":{"type":"boolean"},"rentEpoch":{"type":"integer","format":"int64"},"space":{"type":"integer","description":"Data length in bytes."},"data":{"description":"Account data; encoding depends on request encoding.","oneOf":[{"type":"string"},{"type":"array","items":{"type":"string"}},{"type":"object","additionalProperties":true}]}}},"JsonRpcErrorResponse":{"type":"object","required":["jsonrpc","id","error"],"description":"JSON-RPC 2.0 error response.","properties":{"jsonrpc":{"type":"string","enum":["2.0"]},"id":{"oneOf":[{"type":"string"},{"type":"integer"}]},"error":{"$ref":"#/components/schemas/JsonRpcError"}}},"JsonRpcError":{"type":"object","required":["code","message"],"description":"Structured JSON-RPC error.","properties":{"code":{"type":"integer","description":"Numeric error code per JSON-RPC 2.0 spec. Common values:\n- `-32700` Parse error\n- `-32600` Invalid Request\n- `-32601` Method not found\n- `-32602` Invalid params\n- `-32603` Internal error\n- `-32003` Unauthorized\n- `-32005` Too Many Requests\n- `-32015` Transaction version not supported\n"},"message":{"type":"string"},"data":{"type":"object","additionalProperties":true}}}},"responses":{"UnauthorizedError":{"description":"Authentication required or invalid.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/JsonRpcErrorResponse"}}}},"ForbiddenError":{"description":"Insufficient permissions for the request.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/JsonRpcErrorResponse"}}}},"TooManyRequestsError":{"description":"Rate limit exceeded for this tier.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/JsonRpcErrorResponse"}}}},"InternalServerError":{"description":"Unexpected server error.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/JsonRpcErrorResponse"}}}}}},"paths":{"/":{"post":{"operationId":"simulateTransaction","summary":"simulateTransaction — Simulate a transaction","tags":["Transactions"],"description":"Simulates sending a transaction to get the effects that would occur if the transaction was committed. The simulation runs against the current state of the blockchain and provides detailed information including logs, account changes, compute units consumed, and any errors that would occur during execution.\n**Parameters**\n\n0. `transaction` (required) — Encoded transaction (signed or unsigned, depending on `sigVerify`).\n1. `config` (optional) — Optional configuration object. Every field is optional; omit the entire object to use defaults.\n","requestBody":{"required":true,"content":{"application/json":{"schema":{"type":"object","required":["jsonrpc","id","method","params"],"properties":{"jsonrpc":{"type":"string","enum":["2.0"],"description":"JSON-RPC protocol version."},"id":{"oneOf":[{"type":"string"},{"type":"integer"}],"description":"Request identifier echoed back in the response."},"method":{"type":"string","enum":["simulateTransaction"],"description":"Must be `simulateTransaction`."},"params":{"type":"array","description":"Positional parameters. Each item below corresponds to one position in the array, in order.","minItems":1,"maxItems":2,"items":{"anyOf":[{"title":"transaction","type":"string","description":"Encoded transaction string."},{"title":"config (optional)","type":"object","description":"Optional configuration object. Every field is optional; omit the entire object to use defaults.","properties":{"commitment":{"$ref":"#/components/schemas/Commitment"},"minContextSlot":{"type":"integer","format":"int64","description":"Minimum slot at which the request can be evaluated. The RPC node will reject the request with a `MinContextSlotNotReached` error if its current root is below this value. Use this for read-after-write consistency in multi-step workflows."},"sigVerify":{"type":"boolean","description":"If true, verify the transaction signatures during simulation. Cannot be combined with `replaceRecentBlockhash`. Default false.","default":false},"replaceRecentBlockhash":{"type":"boolean","description":"If true, replace the transaction's recent blockhash with the latest known blockhash before simulating. Cannot be combined with `sigVerify`. Default false.","default":false},"encoding":{"$ref":"#/components/schemas/Encoding"},"accounts":{"type":"object","description":"Specifies which accounts to return after simulation. Use to inspect account state changes the transaction would produce.","properties":{"addresses":{"type":"array","items":{"type":"string","description":"Account pubkey, base-58."},"description":"Pubkeys of accounts whose post-simulation state to return."},"encoding":{"$ref":"#/components/schemas/Encoding"}}}}}]}}}}}}},"responses":{"200":{"description":"Successful `simulateTransaction` response.","content":{"application/json":{"schema":{"allOf":[{"$ref":"#/components/schemas/JsonRpcEnvelope"},{"type":"object","required":["result"],"properties":{"result":{"type":"object","required":["context","value"],"properties":{"context":{"$ref":"#/components/schemas/Context"},"value":{"type":"object","properties":{"err":{"type":"object","nullable":true,"additionalProperties":true},"logs":{"type":"array","items":{"type":"string"}},"accounts":{"type":"array","items":{"$ref":"#/components/schemas/AccountInfo"},"nullable":true},"unitsConsumed":{"type":"integer","format":"int64"},"returnData":{"type":"object","properties":{"programId":{"type":"string"},"data":{"type":"array","items":{"type":"string"}}},"nullable":true}}}}}}}]}}}},"401":{"$ref":"#/components/responses/UnauthorizedError"},"403":{"$ref":"#/components/responses/ForbiddenError"},"429":{"$ref":"#/components/responses/TooManyRequestsError"},"500":{"$ref":"#/components/responses/InternalServerError"}}}}}}
```


---

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