OTP Verification
OTP verification confirms that a person controls a phone number or email by sending a short code that works only once and expires quickly. Businesses use it for sign-ups, logins, deliveries and payment approvals.
What it means
An OTP, or one-time password, is a short code, usually four to six digits, generated for a single use and valid for a few minutes. Your software sends it to the phone number or email the user claims, and the user types it back. If the codes match, the system knows the person has access to that phone or inbox right now.
Where businesses use it
- Signing up with a mobile number, so fake and mistyped numbers never enter your customer list.
- Logging in without remembering a password, which is common in Indian consumer apps.
- Approving a payment or a change of address.
- Confirming delivery, when the customer reads the code out to the delivery person.
Why it matters for your business
Verified numbers make everything downstream more reliable: delivery calls reach real people, WhatsApp updates go to the right customer, and cash-on-delivery fraud becomes harder when an order needs a confirmed phone. OTP is also the usual second step in two-factor authentication, though it is not the strongest one.
Delivery in India
Commercial SMS in India must go through a registered sender and approved message templates under the telecom regulator's DLT rules, so OTP texts need set-up before they work, and messages that stray from the approved wording can be blocked. Many businesses also send OTPs over WhatsApp through the WhatsApp Business API, which suits customers who are already in WhatsApp all day. A voice-call fallback helps older users.
An example
A cloud kitchen in Chennai takes cash-on-delivery orders from its website and loses money on prank orders and wrong numbers. It adds a six-digit OTP at checkout, so the customer must receive the code and enter it before the order is placed. Prank orders become harder to place, delivery calls connect on the first attempt, and order updates reach real customers.
How we build it
When VS Tech Builders adds OTP login or checkout to e-commerce stores and Android apps, we set a short expiry, limit retries and resends so that nobody can guess codes or run up your SMS bill, and avoid storing codes as plain text. Restaurants and cloud kitchens can see more in our page on software for restaurants and cloud kitchens.
Common questions
Why did my customers not receive the OTP SMS?
In India the usual causes are an unregistered sender or template, a message that does not match its approved template, a do-not-disturb setting on the customer's number, or delays at the SMS provider. Check delivery reports with your provider, add a resend button after thirty seconds, and offer WhatsApp or a voice call as alternative channels.
How long should an OTP be valid, and how many tries should it allow?
Five minutes or less is common, and shorter for payments. Allow a small number of wrong entries, such as three to five, before locking the attempt and asking for a new code. Limit resends per hour for each number. Together these rules stop guessing, protect your SMS budget and still feel quick for genuine customers.
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