3. Build Flash Loan

Flash loan transaction manifest

A flash loan transaction typically interacts at least 3 times with components - to get, use and repay the loan. However, depending on the use case, the number of interactions might increase.

Therefore, on a high level, a flash loan transaction manifest can be broken down into:

1. Getting a loan

2. Using a loan

3. Repaying a loan

Below a transaction manifest for a flash loan on Gable is illustrated:

# Gable flash loan transaction

# (1) get loan

# call get flashloan method
#    provide: loan amount
#    return: loan + transient token
CALL_METHOD 
Address("component_rdx1cpmh7lyg0hx6efv5q79lv6rqxdqpuh27y99nzm0jpwu2u44ne243ws") 
"get_flashloan" 
Decimal("<loan_amountt>");

# (2) use loan

# take XRD loan from worktop
TAKE_FROM_WORKTOP 
Address("resource_rdx1tknxxxxxxxxxradxrdxxxxxxxxx009923554798xxxxxxxxxradxrd") 
Bucket("xrd_bucket1");

# for instance call a method that takes some XRD ...
# ... and returns GAB
CALL_METHOD 
"swap"
Address("<some_component_address>") 
Bucket("xrd_bucket1");

# take GAB loan from worktop
TAKE_FROM_WORKTOP 
Address("resource_rdx1tknu3dqlkysz9lt08s7spuvllz3kk2k2yccslfpdk73t4lnznl9jck") 
Bucket("gab_bucket");

# for instance call a method that takes some GAB ...
# ... and returns some XRD
CALL_METHOD 
"swap"
Address("<some_component_address>") 
Bucket("gab_bucket");

# (3) return loan

# take XRD from worktop
TAKE_FROM_WORKTOP 
Address("<resource_tdx_c_1qyqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq40v2wv>") 
Bucket("xrd_bucket2");

# take transient token from worktop
TAKE_FROM_WORKTOP 
Address("resource_tdx_c_1q2xltzyu94nesddh0yyq9h9vuzz5l904n2yt93ltfsssg3ygd5") 
Bucket("transient_bucket");

# call repay flashloan method
#    provide: XRD plus transient token
#    return: residual XRD
CALL_METHOD 
Address("component_tdx_c_1qwxltzyu94nesddh0yyq9h9vuzz5l904n2yt93ltfsssa7pd6s") 
"repay_flashloan" 
Bucket("xrd_bucket2") 
Bucket("transient_bucket");

# the residual XRD (your profit) will be returned to your wallet
CALL_METHOD 
Address("<your_account_address>") 
"deposit_batch" 
Expression("ENTIRE_WORKTOP");

Tailoring this transaction to your use case will require you to (1) fill in open fields:

• <loan_amount>: the loan amount in XRD that you would like to receive.

• <your_account_address>: the account address to which you would like to return the residual XRD of the transaction (you profit).

And (2) overwrite the 'use loan' section with your specific use case.

Note: no method call to “lock_fee” is required – the wallet will add this automatically.