3. Create a simple transaction¶

Creating a transaction requires various steps:

Get the protocol parameters
Calculate the fee
Define the time-to-live (TTL) for the transaction
Build the transaction
Sign the transaction
Submit the transaction

3.1. Get protocol parameters¶

Get the protocol parameters and save them to protocol.json with:

cardano-cli query protocol-parameters \
  --mainnet \
  --out-file protocol.json

3.2. Get the transaction hash and index of the UTXO to spend:¶

cardano-cli query utxo \
  --address $(cat payment.addr) \
  --mainnet

                            TxHash                                 TxIx        Amount
----------------------------------------------------------------------------------------
4e3a6e7fdcb0d0efa17bf79c13aed2b4cb9baf37fb1aa2e39553d5bd720c5c99     4         20000000 lovelace

3.3. Draft the transaction¶

Create a draft for the transaction and save it in tx.draft

Note that for --tx-in we use the following syntax: TxHash#TxIx where TxHash is the transaction hash and TxIx is the index; for --tx-out we use: TxOut+Lovelace where TxOut is the hex encoded address followed by the amount in Lovelace. For the transaction draft –tx-out, –invalid-hereafter and –fee can be set to zero.

cardano-cli transaction build-raw \
--tx-in 4e3a6e7fdcb0d0efa17bf79c13aed2b4cb9baf37fb1aa2e39553d5bd720c5c99#4 \
--tx-out $(cat payment2.addr)+0 \
--tx-out $(cat payment.addr)+0 \
--invalid-hereafter 0 \
--fee 0 \
--out-file tx.draft

3.4. Calculate the fee¶

A simple transaction needs one input, a valid UTXO from payment.addr, and two outputs:

Output1: The address that receives the transaction.
Output2: The address that receives the change of the transaction.

Note that to calculate the fee you need to include the draft transaction

cardano-cli transaction calculate-min-fee \
--tx-body-file tx.draft \
--tx-in-count 1 \
--tx-out-count 2 \
--witness-count 1 \
--byron-witness-count 0 \
--mainnet \
--protocol-params-file protocol.json

> 167965

3.5. Calculate the change to send back to payment.addr,¶

all amounts must be in Lovelace:

expr <UTXO BALANCE> - <AMOUNT TO SEND> - <TRANSACTION FEE>

For example, if we send 10 ADA from a UTxO containing 20 ADA, the change to send back to payment.addr after paying the fee is: 9.832035 ADA

expr 20000000 - 10000000 - 167965

> 9832035

3.6. Determine the TTL (time to Live) for the transaction¶

To build the transaction we need to specify the TTL (Time to live), this is the slot height limit for our transaction to be included in a block, if it is not in a block by that slot the transaction will be cancelled. So TTL = slot + N slots. Where N is the amount of slots you want to add to give the transaction a window to be included in a block.

Query the tip of the blockchain:

cardano-cli query tip --mainnet

Look for the value of slotNo

{
    "blockNo": 16829,
    "headerHash": "3e6f59b10d605e7f59ba8383cb0ddcd42480ddcc0a85d41bad1e4648eb5465ad",
    "slotNo": 369200
}

Calculate your TTL, for example: 369200 + 200 slots = 369400

3.7. Build the transaction¶

We write the transaction in a file, we will name it tx.raw.

cardano-cli transaction build-raw \
--tx-in 4e3a6e7fdcb0d0efa17bf79c13aed2b4cb9baf37fb1aa2e39553d5bd720c5c99#4 \
--tx-out $(cat payment2.addr)+10000000 \
--tx-out $(cat payment.addr)+9832035 \
--invalid-hereafter 369400 \
--fee 167965 \
--out-file tx.raw

3.8. Sign the transaction¶

Sign the transaction with the signing key payment.skey and save the signed transaction in tx.signed

cardano-cli transaction sign \
--tx-body-file tx.raw \
--signing-key-file payment.skey \
--mainnet \
--out-file tx.signed

3.9. Submit the transaction¶

cardano-cli transaction submit \
--tx-file tx.signed \
--mainnet

3.10. Check the balances¶

We must give it some time to get incorporated into the blockchain, but eventually, we will see the effect:

cardano-cli query utxo \
    --address $(cat payment.addr) \
    --mainnet

>                            TxHash                                 TxIx         Amount
> ----------------------------------------------------------------------------------------
> b64ae44e1195b04663ab863b62337e626c65b0c9855a9fbb9ef4458f81a6f5ee     1         9832035 lovelace

cardano-cli query utxo \
    --address $(cat payment2.addr) \
    --mainnet

>                            TxHash                                 TxIx         Amount
> ----------------------------------------------------------------------------------------
> b64ae44e1195b04663ab863b62337e626c65b0c9855a9fbb9ef4458f81a6f5ee     0         10000000 lovelace

Note--mainnet identifies the Cardano mainnet, for testnets use --testnet-magic 1097911063 instead.