SignAndSendTransaction
Once connected to Backpack, an application can ask the user for permission to send transactions on their behalf.
In order to send a transaction, an application must:
1. Create an unsigned transaction.
2. Have the transaction be signed and submitted to the network by the user's Backpack wallet.
3. Optionally await network confirmation using a Solana JSON RPC connection.
Base URL
https://backpack.app/ul/v1/signAndSendTransaction  Query String Parameters
- dapp_encryption_public_key(required): The original encryption public key used from the app for an existing Connect session.
- nonce(required): A nonce used for encrypting the request, encoded in base58.
- redirect_link(required): The URI where Backpack should redirect the user upon completion. Please review Specifying Redirects for more details. URL-encoded.
- payload(required): An encrypted JSON string with the following fields:
{
  "transaction": "...", // serialized transaction, base58-encoded
  "sendOptions": "..." // an optional Solana web3.js sendOptions object
  "session": "...", // token received from the connect method
}- transaction(required): The transaction Backpack will sign and submit is serialized and encoded in base58.
- sendOptions(optional): An optional object that specifies options for how Backpack should submit the transaction. This object is defined in Solana web3.js.
- session(required): The session token received from the Connect method. Please see Handling Sessions for more details.
Returns
Approve
- nonce: A nonce used for encrypting the response, encoded in base58.
- data: An encrypted JSON string. Refer to Encryption to learn how apps can decrypt- datausing a shared secret. Encrypted bytes are encoded in base58.
// content of decrypted `data`-parameter
{  
    "signature": "..." // transaction-signature
}- signature: The first signature in the transaction can be used as its transaction id.
Reject
An errorCode and errorMessage as query parameters. Please refer to Errors for a full list of possible error codes.
{          
    "errorCode": "...",          
    "errorMessage": "..."          
}  