# Saving Failed Transactions (April 2020)
Since node version 1.2.4, after activation of feature #15 “Ride V4, VRF, Protobuf, Failed transactions” the transaction validation procedure is changed.
Invoke script transactions and exchange transactions are saved on the blockchain and a fee is charged for them even if the dApp script or the asset script failed, provided that the sender's signature or account script verification passed.
However if the callable function failed with an error or throwing an exception before the complexity of performed computations exceeded the threshold for saving failed transactions, the transaction is rejected and the fee is not charged.
A fee for the invoke script transaction cannot be funded by transfer from dApp to the transaction sender. If sender's balance is insufficient to pay the fee, dApp script is not executed.
More details about transaction validation
In the JSON representation of the transaction, the applicationStatus field is added, which contains the result of validation:
succeeded– the transaction is successful.script_execution_failed– dApp script or asset script failed. Such a transaction doesn't entail changes in balances (other than charging a fee) and account data storages.
Failed transactions are implemented in the Waves protocol and are supported both by Node Scala and Node Go, as well as by the following Waves tools.
# Node API
Added the applicationStatus field to the following endpoints:
/blocks/{id}/blocks/address/{address}/{from}/{to}/blocks/at/{height}/blocks/last/blocks/seq/{from}/{to}/transactions/address/{address}/limit/{limit}/transactions/info/{id}/transactions/status
How to access: use the pool of Waves nodes with public API:
- Mainnet: https://nodes.wavesnodes.com/
- Testnet: https://nodes-testnet.wavesnodes.com/
- Stagenet: https://nodes-stagenet.wavesnodes.com/
See also the list of Node API changes in release 1.2
# Libraries
# waves-transactions
The waitForTx and waitForTxWithNConfirmations return Promise of transaction which is resolved when the transaction is added to the blockchain. Now the applicationStatus field has been added to the transaction.
How to access: install the latest version of the library using the command
npm i @waves/[email protected]
waves-transactions documentation
# node-api JS
The fetchInfo and fetchStatus functions now support the applicationStatus field.
How to access: install the latest version of the library using the command
npm i @waves/[email protected]
# Waves Explorer
Transactions with failed dApp script or asset script results are displayed. In the list of transactions, they are marked with
icon.
For invoke script transactions the dApp script result is displayed as a table.
How to access: go to https://wavesexplorer.com/.
# Waves IDE
The applicationStatus field for transactions that is added to the blockchain is now supported in JavaScript console and in tests.
Please note: tests now need to check not only that the transaction is added to the blockchain, but also the success of the script.
How to access: go to https://waves-ide.com/.
# Surfboard
The applicationStatus field is now supported for transactions added to the blockchain.
How to access: install the latest version using the command
npm i @waves/[email protected]
# Dapp Ui
For the invoke script transaction, in addition to the transaction status on the blockchain, the status of script execution is displayed.
How to access: go to https://waves-dapp.com/.