Also called: OTP
What a One-Time Password is
An OTP is a short code that works for one authentication event, such as a sign-in or an online payment. In a common card payment flow, the customer enters a code sent to a phone number registered with their card account. The code confirms access to that channel, not a person's identity by itself.
The code expires or becomes unusable after it is used. Expiration periods differ by system, so there is no single duration that applies to every OTP. Treat an unexpected OTP request as a warning: someone could be trying to use a card or access an account.
An OTP confirms access to a channel, not a person's identity, and it adds friction as well as a security check.
How OTP fits into an online payment
An OTP adds a verification step to a card-not-present checkout. The customer enters payment details, receives a code through the configured channel, then enters that code in the payment flow. If the code is missing, incorrect, or expired, the authentication step can fail and interrupt the purchase.
OTP is one authentication method, not a synonym for Multi-Factor Authentication (MFA). MFA requires two or more different factor types, such as something you know and something you possess. An OTP sent to a phone can serve as a possession factor, but using an OTP alone does not automatically make a process MFA.
What OTP means for your costs and risk
An OTP is an authentication step, not a card-processing fee. It does not change interchange or network assessments. Any added cost would come from an authentication or fraud-prevention service your business chooses, so look for that service as a separate charge rather than treating the code as a fee.
The business tradeoff is security versus checkout friction. An extra code can block a payment when a customer cannot access the registered phone or the message arrives late. A code can also be stolen through a fake website or a scam that persuades a customer to share it. OTP lowers some risks, but it does not eliminate payment fraud or guarantee approval.
What you can actually change
You decide where an OTP step belongs in your payment flow and how you support customers who cannot complete it. Keep the instructions clear, and never ask customers to tell an employee their code.
- Use OTP for transactions or account actions where the added verification is worth the checkout friction.
- Tell customers where the code will arrive and where to enter it, without asking them to share it with staff.
- Track OTP failures, abandoned checkouts, and fraud outcomes to see whether the added step helps your business.
- Review authentication-service charges separately from interchange, network fees, and processor markup.
- Map the checkout step. Test the full customer flow, including what happens when a phone is unavailable or a code expires.
- Protect the code. Train staff to direct customers to the secure checkout screen and never request the OTP themselves.
- Measure the result. Compare OTP failures and abandoned checkouts with fraud outcomes before expanding its use.
Frequently asked questions
What is an OTP in a card payment?
It is a temporary code used to verify an authentication step during an online card payment. The customer enters the code in the payment flow, often after it is sent to a phone number registered with the card account.
Is an OTP the same as MFA?
No. An OTP is one authentication method. MFA combines at least two different factor types, such as a password and proof of access to a phone. An OTP by itself does not automatically make a login or payment process MFA.
Does using OTP add a fee to card transactions?
The OTP itself is an authentication step, not a card-processing fee. A business could have a separate charge for an authentication or fraud-prevention service, so review those charges independently from interchange, network fees, and processor markup.