I have the categorizer send such transactions to a temporary "limbo account". So I have two transactions:
# This TX is imported from checking acct statement:
2020-05-15 * "ACH Payment BankA credit card"
Assets:BankA:Checking -500
Equity:Limbo:CreditCardPayments
# This TX is imported from credit card statement:
2020-05-16 * "Payment applied THANK YOU"
Liabilities:BankB:CreditCard 500
Equity:Limbo:CreditCardPayments
After doing a bout of imports, I look at the Limbo account, which should always sum to zero. Sometimes the two TXs don't appear on the same day, so occasionally there's a temporary balance there but that's fine.
I use the same to match up my direct deposits (one end from paystubs import, other from checking account), wire transfers between banks/brokerage, etc. I tend to put them in different subaccounts of "Equity:Limbo" so that I can more easily spot any discrepancies.
Edit: Should've first read the previous reply that says the same thing!
https://github.com/redstreet/beancount_reds_plugins/tree/mas...
Often (in the US) the dates are different- debit from the bank on day X, post to credit card on day X + 1 or X + 2. For my stuff I want the dates in beancount to reflect the dates on the respective statements, so that the balances, which are date-specific, match.
So I capture these as two transactions. I do it as- debit the bank, credit the "ether", then debit the "ether" credit the credit card.
Beancount just wants the postings within a literal transaction to sum to zero. If this conceptual transaction is split into two literal transactions, with some fictional bridge account in between, they can live in different beancount files.
My understanding is that the whole transaction has to live in one file with Beancount. This doesn't seem amenable to having each bank statement generate a single Beancount output file.
But I could be wrong. I don't know how Beancount's importer works.