How to make a transaction using the web IDE
The Simplicity Web IDE is a browser-based development environment for writing, compiling, and deploying Simplicity contracts to Liquid testnet.
Repository: https://github.com/BlockstreamResearch/simplicity-webide Live Demo: (Deploy locally or https://ide.simplicity-lang.org)
Features: - Write SimplicityHL contracts in browser - Compile to Simplicity bytecode - Generate P2TR addresses - Build transactions - Deploy to Liquid testnet
The SimplicityHL web IDE can only make a restricted form of transaction: There is 1 transaction input, 1 transaction output and 1 fee output (Liquid has explicit fee outputs). Confidential transactions or assets other than Bitcoin are not supported.
Write the main function
Open the SimplicityHL web IDE and write the main function of your program.
You can leave the default main function as it is. Customize it if you want.
Generate an address
Click the "Address" button to copy the address of your program to the clipboard.
Leave the web IDE tab open. You will need it later.
Fund the address
Paste the address into the Liquid testnet faucet and press the "Send assets" button.
Copy the ID of the funding transaction to your clipboard.
Look up the funding transaction
Paste the ID of the funding transaction into the Blockstream Explorer for Liquid testnet.
Scroll down and find the SimplicityHL UTXO. The Liquid testnet faucet always sends 100000 tL-BTC. In our example, the SimplicityHL UTXO is vout = 1.
Enter UTXO data into the web IDE
Enter the ID of the funding transaction and the vout into the web IDE.
You can leave the remaining fields as they are. Feel free to customize.
Sign the spending transaction
Click the "Sig 0" button to generate a signature for a transaction that spends the SimplicityHL UTXO.
Paste the signature into the mod witness {...} section.
Generate the spending transaction
Click the "Transaction" button to copy the spending transaction to your clipboard.
Broadcast the spending transaction
Paste the spending transaction into the Blockstream Liquid testnet explorer and click the "Broadcast transaction" button.
If everything worked, the explorer will open the broadcast transaction. In this case, congratulations, you made a SimplicityHL transaction on Liquid testnet!!! You can also look up your transaction on mempool.space.
If you see an error message, take a look at the following "Troubleshooting" section.
Cryptic error message
Cause.
Action to take.
"Transaction not found" (Blockstream Explorer)
Fake error. The transaction actually worked :)
Wait for 1 minute and reload the page.
bad-txns-inputs-missingorspent
The UTXO doesn't exist.
Double check the txid. You might have to wait for one minute for the UTXO to be included in the blockchain.
bad-txns-in-ne-out, value in != value out
The input value does not equal the output value.
Double-check the UTXO info (vout and value). Check that the fee is lower than the input value.
bad-txns-fee-outofrange
The fee does not cover the transaction weight.
Increase the fee.
non-final
The lock time is higher than the current block height.
Decrease the locktime or wait until the block height is high enough.
non-BIP68-final
The sequence is higher than the current block height plus the UTXO height.
Decrease the sequence or wait until the block height is high enough.
dust
You are creating a dust transaction output.
The fee consumes the entire input value. Decrease the fee.
non-mandatory-script-verify-flag (Assertion failed inside jet)
A Simplicity jet fails.
Double-check the conditions that your SimplicityHL program enforces. Update the witness data or transaction parameters.
Every time you change the transaction parameters, the signature hash of the transaction changes. In this case, you need to regenerate signatures using the "Key Store" tab.
non-mandatory-script-verify-flag (Witness program hash mismatch)
The CMR of the Simplicity program inside the UTXO is different from the CMR of the program inside the transaction input.
Use a backup to restore the original program that you used to create the UTXO. Alternatively, try to fix your current program to match the UTXO program.
Web IDE Internals
What Happens When You Compile
Code reference: simplicity-webide/src/compile.rs
- Parse SimplicityHL source
- Compile to Simplicity
- Compute CMR
- Generate P2TR address with internal key:
- Display results
Transaction Building
What the IDE does:
- Create transaction structure
- Build sighash from transaction data + genesis hash
- Satisfy Simplicity program with witness
- Encode program and witness to bytes
- Build complete witness stack
- Serialize transaction to hex
Next Steps
- Learn SimplicityHL: Language Reference
- CLI Development: Simply CLI Guide
- Use Cases: Example Contracts