SMS OTP Verification
Send one-time passwords for sign-up, login, password resets and payments through your own Twilio account. MonoChat workflows handle timeouts, retries and fallback, and keep a record of every code you send.
Or start with $150 of credit, enough for a first month of Growth
Nova Bank: 482913 is your login code. It expires in 5 minutes. Never share it with anyone, including our staff.
08:41
Nova Bank: you signed in on a new device (Chrome on Windows). Not you? Reply NO.
08:42
NO
08:45
Security check started
New device · Chrome on Windows
Security team notified
Thank you. We have flagged this sign-in and our security team will contact you shortly.
08:45
How it works
Your app stays in charge of creating and checking the code. MonoChat sends it through your Twilio account and manages everything around the message.
Nova Shop: 739204 is your password reset code. Valid for 10 minutes.
14:02
Nova Shop: here is a new code, 615830. Your previous code no longer works.
14:04
Password changed
Nova Shop account
Today at 14:05
Nova Shop: your password was changed. Not you? Reply NO and our team will help.
14:05
Features
Twilio delivers the SMS. MonoChat decides when to send, what to do when it fails and who sees the result.
Send one-time codes for phone verification, sign-up and two-factor login from your Twilio number.
Let customers recover access with a code sent to the phone number on file.
Workflows decide what happens when a code is not delivered or not used in time.
Trigger an OTP workflow from your app or backend, or generate the code in a MonoChat custom function.
Send sign-in, payment and account-change alerts, and route a NO reply straight to your team.
See what was sent, when and what happened next, with access limited by role.
Example messages
Three common verification moments, and what the customer sees on their phone.
Confirm the number belongs to the new customer before the account goes live.
Nova Fit: 204617 is your verification code. Enter it in the app to finish signing up. Valid for 5 minutes.
19:20
Welcome to Nova Fit! Your number is verified. Reply STOP to opt out of SMS updates.
19:21
Give the courier a code so the parcel reaches the right person.
Nova Store: your parcel arrives today between 14:00 and 16:00. Give the courier the code 5821 at delivery.
09:10
Can my neighbour at number 12 take it?
09:32
Yes, just share the code with your neighbour. We have added a note for the courier.
09:32
Ask for a code before a payment goes through, and catch fraud with a single reply.
Nova Pay: 551204 confirms your payment of $250.00 to Nova Electronics. If you did not start this payment, reply NO.
13:15
NO
13:16
The payment has been stopped. Our fraud team will contact you shortly.
13:16
Best practices
Short, clear verification messages are delivered, read and used faster, and they cost less.
Four steps from your Twilio account to a working verification flow.
Add your Twilio credentials and the number you use for verification messages.
Start it from your app by API, and write the message with the code, your brand name and the expiry time.
Choose resend limits, timeouts and whether to fall back to WhatsApp or email when SMS fails.
Track sends, failures and fallbacks in MonoChat and refine the flow as you learn.
Verification steps that fit the way each sector protects its customers.
Related Twilio pages and guides to plan your verification channel.
FAQ
How OTP codes are sent, what happens when they fail, and how to keep them secure and affordable.
An SMS OTP (one-time password) is a short code sent by text message to confirm that a person controls a phone number. It is used for sign-up, two-factor login, password resets and payment confirmation. Each code works once and only for a short time.
Connect your Twilio account to MonoChat and create an OTP workflow. Your app (or a MonoChat custom function) generates the code and starts the workflow by API, MonoChat sends the SMS from your Twilio number, and your app checks the code the customer enters.
The workflow can resend the code within the limits you set, wait for a timeout and then fall back to another channel such as WhatsApp or email, or hand the case to an agent. Every attempt is recorded, so your support team can see what happened.
SMS codes are widely used and much stronger than a password alone, but they can be intercepted through SIM swap or phishing. Keep codes short-lived, limit attempts, tell customers never to share them and add a stronger factor for high-risk actions.
Keep the validity short, typically a few minutes, and accept each code only once. Your app sets the expiry, and the message states it so customers know how long they have.
Twilio bills each SMS to your Twilio account at its per-segment price for the destination country. Keeping the message within one segment (160 GSM-7 or 70 Unicode characters) and limiting resends keeps costs predictable. Your MonoChat plan is billed separately.
First month of Growth on us
Connect Twilio, build your verification workflow with retries and fallback, and track every code from one dashboard.
One code per business • 30 days to redeem • No card needed
Start with $150 of MonoChat credit.
$150 to get started.
One code per business, 30 days to redeem, no card needed.