Encode submission

This endpoint accepts an EncodeSubmissionRequest, which internally is a UserTransactionRequestInner (and optionally secondary signers) encoded as JSON, validates the request format, and then returns that request encoded in BCS. The client can then use this to create a transaction signature to be used in a SubmitTransactionRequest, which it then passes to the /transactions POST endpoint.

To be clear, this endpoint makes it possible to submit transaction requests to the API from languages that do not have library support for BCS. If you are using an SDK that has BCS support, such as the official Rust, TypeScript, or Python SDKs, you do not need to use this endpoint.

To sign a message using the response from this endpoint:

  • Decode the hex-encoded string in the response to bytes.

  • Sign the bytes to create the signature.

  • Use that as the signature field in something like Ed25519Signature, which you then use to build a TransactionSignature.



curl --request POST \
  --url https://aptos-mainnet.blastapi.io/<project-id>/v1/transactions/encode_submission \
  --header 'Content-Type: application/json' \
  --data '{
  "sender": "0x88fbd33f54e1126269769780feb24480428179f552e2313fbe571b72e62a1ca1 ",
  "sequence_number": "32425224034",
  "max_gas_amount": "32425224034",
  "gas_unit_price": "32425224034",
  "expiration_timestamp_secs": "32425224034",
  "payload": {
    "type": "entry_function_payload",
    "function": "0x1::aptos_coin::transfer",
    "type_arguments": [
    "arguments": [

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