Documentation Index
Fetch the complete documentation index at: https://docs.blnkfinance.com/llms.txt
Use this file to discover all available pages before exploring further.
These examples combine multiple checks in one rule.
They are helpful when one field on its own is not enough, but a combination of amount, account type, or metadata creates a stronger signal.
Block if previous failed
This rule blocks a very large transaction when the previous transaction status for the same flow was already marked as failed. It assumes your upstream system writes the prior status into metadata before the transaction reaches Watch.
rule BlockIfPreviousFailed {
description "Blocks a large transaction when the previous related transaction failed."
when metadata.previous_transaction_status == "failed"
and amount > 700000
then block
score 1.0
reason "Previous related transaction failed and the current amount is high"
}
Business account personal spending
This rule reviews business-account transactions that land in merchant categories commonly associated with personal spending. It is useful for expense, card, and treasury programs that want to catch obvious policy misuse early.
BusinessAccountPersonalSpending.ws
rule BusinessAccountPersonalSpending {
description "Flags likely personal spending from a business account."
when metadata.account_type == "business"
and metadata.merchant_category in ("retail", "entertainment", "restaurant", "personal_services")
then review
score 0.4
reason "Potential personal spending from a business account"
}
Cross border transaction check
This rule reviews higher-value transactions when the source and destination countries do not match. It is a good example of comparing one metadata field against another value from the current transaction.
CrossBorderTransactionCheck.ws
rule CrossBorderTransactionCheck {
description "Reviews high-value transactions that cross borders."
when metadata.source_country != $current.metadata.destination_country
and amount > 1000
then review
score 0.5
reason "Large cross-border transaction requires review"
}
Dormant account activity
This rule reviews transactions from accounts that have been inactive for a long time and suddenly become active again. It is useful for spotting account takeover, mule activity, or stale credentials being reused.
DormantAccountActivity.ws
rule DormantAccountActivity {
description "Flags high-value activity after a long period of dormancy."
when metadata.days_since_last_transaction > 90
and amount > 1000
then review
score 0.7
reason "High-value transaction after extended account inactivity"
}
Foreign currency transaction
This rule reviews larger transactions when the transaction currency differs from the account’s base currency. It is a practical pattern for detecting unusual cross-currency behavior without blocking normal low-value activity.
rule ForeignCurrencyTx {
description "Flags large transactions in a currency different from the account base currency."
when currency != $current.metadata.account_base_currency
and amount > 1000
then review
score 0.4
reason "Large transaction in a foreign currency"
}
Low KYC daily limit
This rule reviews a transaction when a low-tier KYC customer exceeds the per-transaction or daily limit assigned to them. It relies on your application passing the limit into metadata so the threshold can differ by customer.
rule LowKycDailyLimit {
description "Flags low-tier KYC customers that exceed their configured limit."
when metadata.kyc_tier == 1
and amount > $current.metadata.daily_limit
then review
score 0.5
reason "Transaction amount exceeds the configured limit for a tier-1 user"
}
Low KYC high risk
This rule reviews lower-KYC customers when they transact in a high-risk merchant category and the amount is material. It is a common pattern for tightening controls on newer or less verified accounts.
rule LowKycHighRisk {
description "Flags high-risk category activity from a low-tier KYC customer."
when metadata.kyc_tier == 1
and metadata.merchant_category in ("gambling", "cryptocurrency", "adult", "high_value_goods")
and amount > 500
then review
score 0.8
reason "Low-KYC account is transacting in a high-risk category"
}
Merchant issuer mismatch
This rule reviews card transactions when the merchant country does not match the issuer country. It is a simple geo-mismatch control that can be combined with other travel, device, or authentication signals.
MerchantIssuerMismatch.ws
rule MerchantIssuerMismatch {
description "Flags country mismatches between the merchant and card issuer."
when metadata.merchant_country != $current.metadata.card_issuer_country
then review
score 0.4
reason "Merchant country does not match card issuer country"
}
New account first day
This rule reviews larger transactions from very new accounts. It helps catch abuse patterns where bad actors create a fresh account and immediately try to move significant value.
rule NewAccountFirstDay {
description "Flags high-value activity on the first day of a new account."
when metadata.account_age_days < 1
and amount > 1000
then review
score 0.6
reason "Large transaction from a newly created account"
}
Self transfer check
This rule reviews large self-transfers by checking whether the source and destination are the same. It is useful for spotting circular movement, layering, or attempts to manipulate downstream controls.
rule SelfTransferCheck {
description "Flags large transfers where the source and destination are the same."
when source == $current.destination
and amount > 3000
then review
score 0.45
reason "Large self-transfer detected"
}
Suspicious description check
This rule reviews high-value transactions when an upstream process has already normalized the free-form description into a suspicious keyword. It is a good fit when you want predictable rule logic without relying on complex text parsing inside the DSL.
SuspiciousDescriptionCheck.ws
rule SuspiciousDescriptionCheck {
description "Flags high-value transactions tagged with suspicious description keywords."
when metadata.description_keyword in ("btc", "bitcoin", "crypto", "gift_card", "western_union")
and amount > 1000
then review
score 0.7
reason "Suspicious description keyword found on a high-value transaction"
}
See also Setting conditions and Defining verdicts.
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