AVS response codes explained | Helcim fraud prevention

When you're processing online orders, the Address Verification Service (AVS) is a tool that checks if a customer's billing address information matches what their card-issuing bank has on file. Understanding the AVS response codes is especially important when you're fine-tuning your Helcim Fraud Defender settings.

This guide will help you decode these responses so you can make informed decisions about which codes to accept, tailoring your fraud protection to your business needs.

In this article

The lowdown on AVS codes: why they matter

AVS provides valuable feedback on the address entered during an online transaction. As a Helcim merchant, the main place you'll interact with these AVS codes is within your Helcim Fraud Defender settings.

When you choose to use the AVS Auto-Void feature, you'll select which AVS response codes your business will accept. This article will help you understand what each code means so you can configure those settings confidently.

AVS Quick Facts
AVS provides risk insights, not guarantees. It doesn't approve or decline a transaction on its own. Postal/ZIP code matches are generally more reliable indicators than street address matches (which can vary due to formatting). AVS is widely supported by banks in Canada and the U.S. You can configure AVS settings in Helcim Fraud Defender to automatically manage transactions based on AVS responses.

General AVS response codes

When configuring the AVS Auto-Void feature in Helcim Fraud Defender, you'll be working with a list of common AVS response codes. Here’s what they generally mean.

These are used by Mastercard, Discover, and American Express, and often by Visa as well.

AVS Code	Description	What it means for you
A	Address (street) matches, ZIP does not	Partial match. Customer's street number is right, but their postal/ZIP isn't. Consider if this is acceptable for your risk level.
E	AVS error	An error occurred during the AVS check. You might treat this as a non-match when setting your rules.
N	No match on address (street) or ZIP	High risk. Neither the street address nor the postal/ZIP code matched. Many merchants choose not to accept this.
R	Retry, system unavailable or timed out	The AVS system was temporarily down. For auto-void rules, you might treat this as a non-match.
S	Service not supported by issuer	The cardholder's bank doesn't support AVS. You can't get a match, so this code often needs to be accepted if you take many such cards, relying on other factors.
U	Address information is unavailable (domestic issuer)	Information couldn't be verified. Similar to 'S', you'll need to decide if you accept this based on your risk.
W	9 digit ZIP matches, address (street) does not	Common in the US (ZIP+4). The full ZIP is good, but the street doesn't match. Assess your comfort with this.
X	Exact AVS match (street and 9 digit ZIP)	Strong match (primarily US). Highest level of AVS confidence. Typically accepted.
Y	Address (street) and 5 digit ZIP match	Strong match. Both street and standard postal/ZIP match. Typically accepted.
Z	5 digit ZIP matches, address (street) does not	Partial match. Postal/ZIP is good, but street isn't. Assess your comfort.

How AVS codes work with Helcim Fraud Defender

As mentioned, the primary way you'll use this AVS code knowledge is when setting up Helcim Fraud Defender.

Go to All Tools > Settings > Helcim Defender.
Enable Helcim Fraud Defender if it's not already.
Toggle AVS Auto-Void to ON.
In the Accepted AVS multi-select box, you will choose which AVS response codes you want to accept. If a transaction receives an AVS code that is not in your "Accepted AVS" list, and AVS Auto-Void is on, the transaction will be automatically voided.

For more details on setting this up, see our article: Using Helcim Fraud Defender.

Next steps

Review your Helcim Fraud Defender settings (specifically the AVS Auto-Void and Accepted AVS options) using the information in this guide.
Decide which AVS codes represent an acceptable level of risk for your business. There's no single "right" answer — it depends on what you sell, your profit margins, and your general tolerance for risk.
Keep this guide handy as a reference for when you're reviewing or adjusting those settings in the future.

FAQs

Where exactly will I see these AVS codes in my Helcim account?

You'll primarily interact with the list of AVS codes when you are in Settings under Helcim Defender, specifically when configuring the Accepted AVS list for the AVS Auto-Void feature.

Which AVS codes should I accept in my Helcim Fraud Defender settings?

This is up to you and your business's risk comfort level. Many merchants choose to accept codes indicating a strong match (like X, Y) and may also accept partial matches or "service not supported" (S, U) if they sell to customers whose banks may not fully support AVS. Declining codes like 'N' (No Match) is a common practice.

If I choose to accept an AVS code like 'S' (Service Not Supported), does that mean the transaction is risky?

Not necessarily. It just means AVS couldn't provide a confirmation. In these cases, other factors like the CVV result, the Helcim Fraud Defender overall score (if you're using score-based auto-void), and your own review become even more important.

Can these AVS codes change?