Online payments often depend on getting a bank account number right. Even small errors can turn into major costs, especially for businesses that process thousands of transactions. Verifying account numbers prevents these failures by confirming that an account is valid, active, and owned by the right person or business. This process also ensures that funds reach their intended destination and helps businesses meet Anti-Money Laundering (AML) and Know Your Customer (KYC) requirements.

Below, we’ll explain what account number verification means, how to verify account numbers, and how businesses are using open banking and real-time application programming interfaces (APIs) to make their transactions more secure and efficient.

What’s in this article?

• What is account number verification?
  
• Why is verifying account numbers important?
  
• How do you verify a bank account number?
  
• What are the best methods for account number verification?
  
• How can businesses verify account numbers securely and reliably?
  
• How Stripe Financial Connections can help
  

What is account number verification?

Account number verification is how businesses confirm that a bank account number is real, active, and belongs to the person or company that’s trying to use it.

There are two main layers to account number verification:

• Validation: This checks that the number has the right length, format, and structure for the country or bank in question.

• Verification: This confirms that the account exists and is owned by the right person.

Some systems only validate, catching typos or impossible combinations. Others fully verify by confirming ownership through the bank. Together, these steps create a foundation of accuracy and security in any transaction.

Why is verifying account numbers important?

The costs of inadequate verification are high so banking systems invest in improved verification to combat fraud and misdirected payments. Banks in Belgium, for example, began rolling out a name check service in 2025 that notifies senders when the beneficiary’s name and International Bank Account Number (IBAN) don’t match.

Here’s how account verification services protect both sides of a payment:

• Error prevention: A single mistyped digit can send money to the wrong account or cause a payment to fail altogether. Verification catches these mistakes before funds move, which saves time and avoids costly reversals.

• Fraud prevention: Verifying account ownership helps prevent unauthorized transfers, fake accounts, and payment redirection scams.

• Compliance support: Payment compliance guidelines, from US Automated Clearing House (ACH) rules to European AML standards, often require account verification as part of KYC procedures.

• Efficiency: Failed payments lead to manual work, reconciliation issues, and reputational damage.

How do you verify a bank account number?

To verify a bank account number, businesses can use a mix of manual checks, automated systems, and bank integrations.

The following measures can confirm that an account is valid and owned by the right person:

• Cross-checking with bank records: Some banks and payment systems offer tools that confirm whether a given account number and name match what’s on file, such as the Confirmation of Payee service in the UK.

• Microdeposits: Businesses send 1 or 2 small test deposits, such as $0.06 and $0.12, and ask the account holder to report the amounts. If the account holder can see and confirm the payments, that proves they are the rightful owner of the account.

• Instant verification through secure login: Customers log in to their online banking through a secure interface, which instantly confirms that the account is valid and active. This method uses encrypted connections and user authorization, not shared credentials potentially stored by a third party, to pull verified data in seconds.

• Open banking and API integrations: In markets with open banking, businesses can verify accounts directly through a bank’s API after the customer gives permission.

• Document-based verification: In some cases, a business might ask for a voided check or a bank statement that shows the account number and name.

Many organizations layer these methods. They use instant verification where possible and fall back on microdeposits or document checks when needed.

What are the best methods for account number verification?

The right method of verification depends on your region, risk level, and how quickly you need confirmation.

Here’s what to consider:

• Speed and user experience: Instant verification through secure login or open banking APIs is the fastest route. Customers authenticate directly with their banks, and the business gets verified account data in seconds. This is ideal for high-volume onboarding or platforms where a delayed setup can cost conversions.

• Coverage and reliability: Microdeposits work across nearly every bank and country, don’t rely on APIs, and are highly resistant to fraud. They’re slower, but as a fallback method, they enable verification even when other systems fail.

• Assurance and compliance: Direct bank API integrations offer the highest accuracy. They typically confirm both ownership and account validity straight from the source, and they’re especially strong in regions where regulation backs the security and transparency of these connections.

• Risk management: Manual verification, such as reviewing a voided check or signed bank letter, is often secure for high-value or high-risk transactions. It adds time and effort but can be a worthwhile option.

In practice, the best strategy is hybrid: use instant verification for users, fall back to microdeposits when necessary, and reserve manual checks for exceptional cases.

How can businesses verify account numbers securely and reliably?

Common bank account data errors fall into three categories: mistyped account numbers or sort codes, incorrect reference numbers, and invalid bank codes due to mergers or changes. As a result, a large portion of verification failures are due to avoidable data entry mistakes or outdated infrastructure.

Businesses can verify account numbers by doing the following:

• Validate for accuracy: The simplest failures are the most common ones. Transfers might fail due to typos, transposed digits, or outdated bank codes. A quick format check for IBANs, routing numbers, or country-specific structures isolates these errors before a transaction even begins.

• Verify ownership directly: The next layer is confirming that the account exists and belongs to the intended owner. Secure microdeposits, API-based checks, or open banking flows accomplish this without ever exposing sensitive information.

• Protect every data exchange: Account numbers and routing details qualify as regulated financial data. They should be encrypted in transit and at rest, tokenized wherever possible, and stored only when necessary. For example, under the General Data Protection Regulation (GDPR) in the EU and California Consumer Privacy Act (CCPA), protecting account information is both a legal and reputational obligation.

• Be transparent with users: Issues in verification often come from confusion, not technology. Clearly explain to customers why the process matters and how data is secured.

How Stripe Financial Connections can help

Stripe Financial Connections is a set of APIs that allows you to securely connect to your customers’ bank accounts and retrieve their financial data, enabling you to build innovative financial products and services.

Financial Connections can help you:

• Simplify onboarding: Offer a seamless, instant bank account verification process that doesn’t require manual identity and account verification.

• Access rich financial data: Retrieve comprehensive information about your customers’ bank accounts, including balances, transactions, and account details.

• Automate recurring payments: Enable your customers to securely link their bank accounts for recurring payments, improving payment success rates.

• Enhance risk management: Analyze customers’ financial data to make more informed decisions about credit, lending, and other financial products.

• Comply with regulations: Financial Connections helps you meet KYC and AML requirements.

• Innovate with confidence: Build new financial products and services on top of the secure, reliable Financial Connections infrastructure.

Learn more about Financial Connections, or get started today.