The finalize_and_extract function performs final validation and produces the raw transaction bytes ready to broadcast to the Zcash network.
Prerequisites Before finalization, ensure:
✅ All transparent inputs are signed
✅ All Orchard proofs are generated
const info = t2z . inspect_pczt ( pczt . to_hex ()); if ( ! info . all_inputs_signed ) { throw new Error ( 'Not all inputs signed' ); } if ( ! info . has_orchard_proofs ) { throw new Error ( 'Orchard proofs not generated' ); }
Function Signature // Get raw bytes function finalize_and_extract ( pczt : WasmPczt ) : Uint8Array // Get hex string (convenient for broadcasting) function finalize_and_extract_hex ( pczt : WasmPczt ) : string
func FinalizeAndExtract ( pczt * Pczt ) ([] byte , error ) func FinalizeAndExtractHex ( pczt * Pczt ) ( string , error )
fun finalizeAndExtract (pczt: Pczt ): ByteArray fun finalizeAndExtractHex (pczt: Pczt ): String
Basic Usage // Get transaction as hex (most common) const txHex = t2z . finalize_and_extract_hex ( pczt ); console . log ( 'Transaction ready:' , txHex . length / 2 , 'bytes' ); // Or get raw bytes const txBytes = t2z . finalize_and_extract ( pczt );
txHex , err := t2z . FinalizeAndExtractHex ( pczt ) if err != nil { log . Fatal ( err ) } fmt . Printf ( "Transaction ready: %d bytes \n " , len ( txHex ) / 2 )
val txHex = finalizeAndExtractHex (pczt) println ( "Transaction ready: ${ txHex.length / 2 } bytes" )
What Happens During Finalization
Spend Finalizer
Assembles final script signatures from partial signatures.
Validation
Verifies all required data is present and valid.
Transaction Extractor
Converts the PCZT into a raw Zcash transaction.
Serialization
Produces the final byte representation.
Broadcasting the Transaction After extraction, broadcast the transaction to the Zcash network:
Using zcash-cli zcash-cli sendrawtransaction "0500000..."
Using lightwalletd // gRPC to lightwalletd const response = await lightwalletClient . sendTransaction ({ data: hexToBytes ( txHex ) }); console . log ( 'Txid:' , response . txid );
Using a Block Explorer Many block explorers provide a “Broadcast” or “Push TX” feature where you can paste the raw transaction hex.
Using JSON-RPC const response = await fetch ( 'https://zcash-rpc.example.com' , { method: 'POST' , headers: { 'Content-Type' : 'application/json' }, body: JSON . stringify ({ jsonrpc: '2.0' , method: 'sendrawtransaction' , params: [ txHex ], id: 1 }) });
Complete Example import * as t2z from '@d4mr/t2z-wasm' ; async function buildAndBroadcast () { // 1. Create PCZT let pczt = t2z . propose_transaction ( inputs , payments , changeAddr , network , expiry ); // 2. Sign all inputs for ( let i = 0 ; i < inputs . length ; i ++ ) { const sighash = t2z . get_sighash ( pczt , i ); const sig = await sign ( sighash , keys [ i ]); pczt = t2z . append_signature ( pczt , i , pubkeys [ i ], sig ); } // 3. Generate proofs pczt = t2z . prove_transaction ( pczt ); // 4. Finalize const txHex = t2z . finalize_and_extract_hex ( pczt ); // 5. Broadcast const txid = await broadcast ( txHex ); console . log ( 'Transaction broadcast:' , txid ); return txid ; }
Transaction Structure The extracted transaction follows the v5 transaction format:
Field Description Header Version, version group ID Transparent Inputs with signatures, outputs Sapling (empty in t2z transactions) Orchard Actions with proofs, binding signature Expiry Block height expiry
Typical sizes:
1 input → 1 Orchard output: ~2.5 KB
1 input → 2 Orchard outputs: ~5 KB
Common Errors
Not all transparent inputs have been signed. Use inspect_pczt to check which inputs need signing. const info = t2z . inspect_pczt ( pczt . to_hex ()); info . transparent_inputs . forEach (( input , i ) => { if ( ! input . is_signed ) { console . log ( `Input ${ i } needs signature` ); } });
Orchard proofs haven’t been generated. Call prove_transaction first.
The PCZT couldn’t be finalized. This usually means something is inconsistent — try rebuilding from scratch.
After Broadcasting After a successful broadcast:
Get the txid — Most broadcast methods return the transaction IDWait for confirmation — Monitor for inclusion in a blockVerify in explorer — Check the transaction on a block explorer
The recipient can view incoming shielded funds using their full viewing key (not spending key). For Orchard, viewing keys are encoded as uview1... (mainnet) or uviewtest1... (testnet).
🎉 Congratulations! You’ve completed the full t2z transaction flow:
✅ Proposed the transaction
✅ Verified (optional)
✅ Signed all inputs
✅ Generated proofs
✅ Finalized and broadcast
Try the Demo See this entire flow in action with the interactive demo.
