Customer Authentication Best Practices for Shopify Stores (2026)

Customer account breaches are now a common entry point for online fraud. In fact, Verizon reports that about 88% of basic web application breaches involve stolen customer login credentials.

Once attackers gain access to an account, they don’t even need to steal credit card numbers to cause damage: They can redeem loyalty balances, place fraudulent orders, or change account details.

The financial impact of these breaches can be devastating. The FBI’s 2024 Internet Crime Report recorded losses exceeding $16 billion from these breaches, a 33% increase from the previous year. And when you consider the lost revenue from potential customers who can’t trust the security of your site, the damage is even worse.

As more commerce moves online and perpetrators of fraud continue to expand and evolve their practices, it’s increasingly important for online businesses to securely verify customer identity. This guide explains how customer authentication works and outlines practical steps Shopify users can take to reduce account takeover risk while keeping login and checkout fast for real customers.

What is customer authentication?

Customer authentication is the process of confirming that a person interacting with your online store is who they claim to be, and that they aren’t interacting with any areas where they should not have access. Authentication takes place at points throughout the customer journey, including when someone logs in, creates an account, contacts support, or completes a verification step before taking a sensitive action.

Customer authentication is part of a broader digital identity framework that connects users, devices, and services. Many merchants rely on identity providers and standards like OpenID Connect to manage identity across systems and ensure seamless integration between login, checkout, and support channels.

Common authentication methods include:

• Entering a password to sign in
• Receiving and entering a one-time code 
• Approving a login on a separate, trusted device
• Using biometric login through a device (like Face ID or fingerprint)
• Using a passkey tied to a device or account
• Completing a step-up check before changing account details

In addition to these methods, many organizations now use multi-factor authentication (MFA), often a combination of password entry plus one of the other methods like a one-time code or approval from another device.

People often confuse customer authentication and payment authentication, but they serve different purposes. Payment authentication verifies that someone is authorized to use a specific payment method for a transaction.

Payment authentication usually happens during checkout and is often handled by the card network, issuing bank, or payment provider. Regional regulations often play a part, as with strong customer authentication (SCA) regulations in the EU and other regions, which require 3D Secure (3DS) verification flows in which a shopper may need to enter a code, approve a prompt from their bank, or complete another verification step before the payment is approved.

Why customer authentication matters more in 2026

Customer authentication is a security control, but it’s also a revenue protection system. When identity verification is weak, attackers can log in to your systems as customers and carry out fraudulent actions that steal your revenue and do further harm to your company. Fraudsters perpetrating account takeovers, loyalty theft, fraudulent orders, support-channel impersonation, and chargebacks will eat into your margins, and cause you to lose customer trust.

Research helps illustrate just how widespread credential-based attacks have become. According to Verizon’s 2024 Data Breach Investigations Report, “Use of stolen credentials as a percentage of initial actions in breaches… is still our top action at 24%.” In web application data breach patterns, the problem is even more concentrated, according to Verizon’s more recent 2025 Data Breach Investigation Report (DBIR), which found “about 88% of the breaches involve the use of stolen credentials.”

In ecommerce, data breaches put customers at risk as well as businesses. Attackers can use passwords from breaches to access sensitive information like stored payment methods, loyalty balances, saved addresses, and order history, some of which they can use to commit further acts of fraud outside of your business.

Multi-factor authentication (MFA) adds protection against password breaches, but it isn’t foolproof — especially when implemented poorly. Attackers increasingly exploit user behavior by repeatedly sending push notifications or verification prompts. This tactic, known as multi-factor authentication fatigue or prompt bombing, is also appearing in incident data. According to Verizon’s 2025 DBIR, “Prompt bombing… [shows] up in 14% of incidents.”

Ultimately, strong authentication protocols are essential for securing your business, preserving revenue, and safeguarding customers.

The core principles of high-converting authentication

While security may be the driving force behind authentication, it’s not the only consideration. The key is to make shopping at your online store safe while adding as little friction as possible to the customer experience (CX). Authentication that keeps your customers safe without chasing them away with too many difficult steps is known as high-converting authentication. 

High-converting authentication follows a few core principles, including:

• Risk-based friction: Add verification only when risk increases. Examples include a login from a new device or unfamiliar location, a large or unusual order value, changes to shipping address or payment details, or multiple failed login attempts.
• Progressive trust: Verification should adjust as confidence in the customer grows over time. First purchases may be guest or accelerated, while returning customers with consistent behavior face fewer repeat checks. New or unusual activity increases scrutiny.
• Make secure paths the easiest paths: The safest login or checkout method should also be the fastest and simplest. Passwordless login, one-time codes, or passkeys require fewer steps than passwords, so many customers will naturally choose the more secure option.
• Recovery is part of authentication: Recovery of an account and support access are identity verification moments, not only service tasks. Password resets, contact detail changes, and support-assisted access require verification because attackers often target these paths to bypass login protections.
• Measure everything: Evaluate authentication using real customer and business outcomes. Track login and checkout completion, verification abandonment, false positives, recovery requests, and fraud or chargeback trends to adjust friction where needed.

Customer authentication best practices

The golden rule of customer authentication is to reduce account takeover risk without adding unnecessary friction to login or checkout. That means choosing authentication methods that customers will use, and applying stronger verification only where it improves security outcomes. 

The practices below focus on what merchants can implement today:

1. Implement passwordless or passkey-first where possible

Passwords are the most common entry point for account takeover because they can be guessed or stolen in other security breaches. Using stolen usernames and passwords from one breach to get into websites is known as “credential stuffing.” The tactic works because even today, many customers still use one password for their email, banking, shopping, and social media—meaning criminals who guess or steal a password from one place can use it just about everywhere.

Passwordless authentication methods remove that risk by eliminating shared secrets that attackers can capture or reuse. Additionally, 61% of consumers see passkeys as a more secure authentication method and 58% see it as more convenient, according to FIDO Alliance.

Passkeys are a passwordless login authentication method tied to a customer’s device. Instead of typing a password, the customer confirms their identity using their phone, computer, or a biometric authentication process like facial identification or a fingerprint. Importantly, the credential never leaves the device, which makes passkeys resistant to phishing and credential stuffing.

Other passwordless options (e.g,, one-time codes sent by email or SMS) also reduce reliance on stored passwords, though they have different trade-offs.

To understand how these authentication methods compare, here’s a practical breakdown:

Modern authentication systems protect stored credentials using secure hashing algorithms, which make passwords unreadable even if systems are compromised. Passwordless authentication also reduces reliance on complexity rules like special characters or memorization requirements that don’t always prevent compromise.

When should merchants prioritize passwordless login or passkeys?

If most customers shop on mobile and repeat purchases are important, prioritize passkeys or passwordless login to authenticate user identity. Device-based authentication works best when customers return from the same device, making repeat sign-in faster and reducing password-related risk.

2. Use step-up authentication for high-risk actions 

Step-up authentication adds an extra identity check only when risk increases, such as when there’s indication someone is trying to gain improper access. Stores may also apply a higher bar for authentication when an action could expose sensitive data, financials, or account control, but would never impose those requirements on standard customer interactions. 

When step-up authentication is triggered, the store temporarily pauses the action and asks the customer to confirm their identity. For example, a customer could confirm their identity by entering a one-time code, approving a biometric prompt, or re-authenticating. Once verified, the customer continues where they left off.

This keeps routine activity fast while protecting the customer and your business in the moments attackers target most.

When should step-up authentication be required?

Require step-up authentication when a customer action directly affects money, identity, or account ownership. The following actions should trigger additional verification:

• Changing shipping address
• Updating or adding a payment method
• Placing unusually large or high-value orders
• Redeeming gift cards, store credit, or loyalty balances
• Logging in after suspicious or abnormal activity

What signals should trigger step-up verification?

Trigger step-up verification when account behavior or context deviates from normal activity. Common signals include:

• Login from a new or unrecognized device
• IP or location anomaly compared to typical behavior
• “Impossible travel” (logins from multiple locations at a significant distance from each other within a short time window)
• Multiple failed login attempts
• Signals associated with automated or bot activity

3. Reduce credential stuffing and bot logins before they hit the login box

Credential stuffing and bot-driven login attacks work by trying huge numbers of stolen usernames and passwords automatically, hoping some will match real accounts.

Stopping these automated attempts before they reach customer accounts helps prevent takeovers and keeps login fast and easy for legitimate users.

Here are some core defenses that stop automated login abuse:

• Rate limiting: Restrict the number of login attempts from a single IP address or session within a set time window. This slows automated attacks and prevents rapid credential testing.
• Device fingerprinting: Identify patterns in devices, browsers, and environments attempting to log in. Repeated activity from suspicious or inconsistent device profiles can be blocked or challenged.
• Web application firewall (WAF) and bot management: Filter traffic before it reaches the login system. These tools detect known bot signatures, abnormal traffic patterns, and automated behavior. Then, they block or challenge those requests.
• Login-throttling: Gradually slow or temporarily block login attempts after repeated failures. This makes large-scale credential testing impractical.

4. Make account recovery harder to abuse than login

Account recovery is a common way attackers take over accounts. If login protections are strong but recovery is weak, attackers may try to reset access rather than use credentials.

For that reason, recovery should require the same level of identity verification as login, or more. Here are some secure reset mechanisms to use for your ecommerce store:

• Time-limited reset links: Password or access reset links should expire quickly to reduce the window of misuse.
• One-time use links: Reset links should work only once to prevent reuse if intercepted or shared.
• Verification before contact changes: Require step-up authentication before changing email addresses or phone numbers, since faked emails and numbers are often used for fraudulent recovery.

It’s also critical to note that customer support introduces a human pathway into account access. Attackers can exploit this by impersonating customers, claiming to be locked out, or requesting urgent changes to contact details.

Support teams should follow structured identity verification procedures before granting access or modifying account information. This means:

• Using defined verification scripts for recovery requests
• Requiring multiple verification factors before making account changes
• Logging and reviewing recovery-related support activity

5. Avoid MFA patterns customers hate (and attackers exploit)

Multi-factor authentication strengthens identity verification, but how it’s implemented matters. Poorly designed MFA can frustrate customers and create new attack opportunities at the same time.

As mentioned earlier, attackers increasingly exploit MFA fatigue. This is when a perpetrator sends repeated authentication requests—often push notifications—until a user approves one. 

Push-only MFA is especially vulnerable because approval requires little effort or context. If customers receive frequent or unexpected prompts, they may automatically approve them without even looking.

Here are some more secure alternatives:

• Number matching: The customer enters a number shown on the login screen into their authentication device. This confirms they are responding to a real request.
• Passkeys or biometric confirmation: Authentication is tied to the customer’s device and requires biometric or device unlock. This makes phishing attacks and remote approval much harder.

These methods reduce accidental approvals and make it significantly more difficult for attackers to trick customers.

How to implement these best practices and authentication systems on Shopify

Shopify has a technological infrastructure built for reliable authentication systems. The Shopify platform includes built-in checkout and identity features that help merchants quickly authenticate returning customers while reducing checkout friction.

The examples below show how real Shopify merchants are using accelerated authentication as an authentication solution to shorten checkout time and improve measurable business outcomes. Let’s take a closer look.

Use accelerated checkout authentication solutions to reduce friction for returning customers

Accelerated checkout is an authentication solution that identifies returning customers and verifies their identity before they even reach the checkout flow. Because their stored information is securely recognized, they don’t need to reenter details, which reduces steps and speeds up purchase completion. Customers appreciate the convenience as well as the acknowledgment of their high-value status.

Shop Pay’s authenticated checkout illustrates how this works in practice. In a four-week test, apparel retailer Princess Polly evaluated the impact of automatically recognizing returning customers with an active Shop Pay session and pre-filling their information during checkout.

The test produced measurable performance gains:

• 4.1% higher conversion among buyers with an existing Shop Pay session
• 1.6% increase in total store orders in the United States and 1% in Australia
• 7.6% reduction in the time it took customers to complete checkout

FragranceNet.com also implemented Shop Pay to improve checkout efficiency and reduce manual data entry. Shop Pay quickly recognizes users and authenticates them with a one-time code, allowing stored payment, shipping, and billing information to populate automatically.

After integrating Shop Pay, FragranceNet.com reported:

• 3.4% increase in conversion rates
• 7.5% growth in new customer acquisition
• Integration completed in 8 weeks with uninterrupted uptime

By combining identity recognition with one-time code authentication, customers could complete purchases in fewer steps, reducing checkout friction while improving both conversion and new customer acquisition.

Improve trust and conversion with Checkout Extensibility and compatible checkout customization

Checkout is a high-stakes part of the customer journey. Many merchants customize checkout to support branding, upsells, or operational needs, but fragile custom code can create additional ongoing risk. It can break when platforms update, require repeated testing, and introduce gaps that affect performance or reliability.

App-based, platform-supported customization reduces these issues. Instead of maintaining custom code, merchants can make checkout changes using tools that are easier to update, test, and manage over time.

Monos is an example of a Shopify merchant that upgraded from checkout.liquid to Checkout Extensibility to simplify how they customized and managed checkout across four global storefronts. Previously, even small changes required locating and modifying code, testing configurations, and repeating the process across multiple stores.

After upgrading, Monos was able to manage checkout customization using app-based tools and platform-supported features instead of maintaining complex custom code.

The results included:

• Over 10 hours per month saved in development time through faster, app-based checkout customization
• Checkout customizations that integrate seamlessly with Shop Pay, resulting in a checkout experience that converts up to 50% better than guest checkout
• A consistently faster checkout experience

The upgrade also reduced the need to repeatedly maintain or troubleshoot fragile checkout code. This allowed the team to manage changes more efficiently across all stores.

Platform-supported customization improves checkout reliability as well. When checkout behavior stays consistent across updates and storefronts, customers experience fewer disruptions, reinforcing trust at the most critical point of purchase.

Extensible checkout customization helps merchants improve conversion while reducing operational complexity and risk. By building on supported platform features rather than maintaining fragile custom code, merchants create checkout experiences that are easier to manage and more reliable over time.

Use customer recognition and unified profiles to support secure recovery and better service

Customer recognition also supports identity continuity across touchpoints, which makes account recovery and checkout more reliable.

When customer data is unified across online and in-store systems, merchants can identify returning customers and verify identity consistently. This reduces the need to reestablish identity in each channel and allows support teams to rely on a single view of the customer. Customers are more susceptible to MFA fatigue if they are forced to log in separately to different parts of your store. 

Orlebar Brown implemented Shopify’s unified commerce platform to connect customer data across online and physical stores. Previously, fragmented systems created multiple versions of customer data, making it difficult to understand behavior or deliver consistent experiences across channels.

After moving to a unified platform, the brand could recognize customers globally and access their purchase history across touchpoints. Store teams could identify customers and provide more personalized service, while checkout became faster for returning shoppers.

The results included:

• 66% increase in basket-to-checkout rate with Shopify Payments
• 42% of customers identified as existing Shop Pay users, enabling frictionless checkout
• Customers recognized across channels with full purchase history visible

Unified customer recognition also improved service interactions. Store staff could see a customer’s history, recommend products based on past purchases, and provide more custom support.