alchemy_requestFeePayer

POST

/{apiKey}

Requests fee sponsorship for a Solana transaction and returns the updated serializedTransaction with the paymaster fee payer set and signed.

On every sponsored request, any top-level SystemProgram.createAccount and Associated Token Program Create/CreateIdempotent instructions are rewritten so the paymaster funds them directly — no opt-in required. For CPI-driven account creation, opt into rent prefunding with prefundRent: true; policies using prefundRent must set maxSpendPerTxnUsd.

CPI rent prefunding is allowlisted. Contact support@alchemy.com for access.

Path Parameters

stringrequireddefaults to docs-demo

For higher throughput, create your own API key

Request

objectrequired

Object containing the policy ID, serialized transaction, and optional rent-prefunding settings.

Responses

200

Object containing the sponsored transaction plus fee and rent estimates.

POST/v2/{apiKey}

curl --request POST \  --url https://solana-mainnet.g.alchemy.com/v2/docs-demo \  --header 'Content-Type: application/json' \  --data '{  "jsonrpc": "2.0",  "id": 1,  "method": "alchemy_requestFeePayer",  "params": [    {      "policyId": "69d524a7-e932-4214-8673-dcdcba31bb42",      "serializedTransaction": "AgICAQMEBQYHCAkKCwwNDg8BCg=="    }  ]}'

200Success

{  "jsonrpc": "2.0",  "id": 1,  "result": {    "serializedTransaction": "AQIDBAUGBwgJCgsMDQ4PEA==",    "estimatedFeeLamports": 5000,    "estimatedRentLamports": 890880,    "usesDurableNonce": false,    "lastValidBlockHeight": 567890  }}

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alchemy_requestFeePayer

Path Parameters

apiKey

Request

params[0]

Responses

200