Email OTP service for signups, logins, and SMS fallback
Send time-limited email OTP codes for signup, login, and secure actions, with delivery in seconds anywhere in the world.
When email OTP is the right channel
The identifier you actually hold
Not every user gives you a phone number, and not every number reaches. In B2B, SaaS, and edtech the email address is often the only verified identifier you actually hold.
Where SMS does not reach
Email also works where SMS does not: DND registrations, international numbers, and carrier failures. It costs less per verification and it does not depend on any telecom operator. For a code-based flow instead, see user verification without an OTP.
Why use email OTP
Four situations where an email code verifies a user that an SMS would not have reached at all.
Ideal for account creation
Not every user shares a phone number. Email OTP verifies identity during signup, which suits tech startups, B2B, SaaS, and edtech products especially well.
Fallback for SMS and 2FA
When SMS fails on DND, delivery issues, or international numbers, email steps in and completes the verification loop.
Better for secure workflows
Email suits login verification in compliance-heavy industries where mobile handset use is restricted on site.
Consistent and cost-effective
Email works globally, does not depend on carrier infrastructure, and costs less per verification than SMS.
Connect with us
Learn how to leverage Celitix's email OTP solution.
Built for developers
An email OTP API, prebuilt integrations, and libraries for whatever your team already writes in.
API-first design
Full control over authentication, independent of your tech stack. The SMS API shares the same credentials.
Prebuilt integrations
Connect to WordPress, Webflow, and more without custom work.
Flexible libraries
Choose from client and server libraries including React, PHP, and NodeJS.
Why choose Celitix for email OTP
Instant email delivery
Users receive codes in seconds, across regions and across ISPs.
Built-in security and privacy
Fully encrypted, with protection at every layer.
White label and multi-channel
Customise the look, and combine with WhatsApp, SMS, voice, or missed call for multi-step verification.
Seamless integrations
Connect the verification flow to your CRM, website, or customer journey, all from one place.
Email OTP as part of multi factor authentication
Email rarely runs alone. These are the combinations businesses actually deploy once one channel proves insufficient.
Email plus SMS
The most common pairing. Email verifies the account, an OTP SMS service confirms high-value actions, and either can cover for the other when delivery fails.
Email plus WhatsApp
Useful where customers read WhatsApp faster than email. It is the multi factor authentication API India teams build on, since the WhatsApp Business API handles both channels from a single call.
Email plus voice
For users who cannot receive text at all, a voice call reads the code. It is the last fallback and it almost always lands.
Email verification API at signup
Check the address is deliverable before you send anything to it, which keeps bounce rates down and your sender reputation intact.
Use every channel from one account
Run email OTP alongside every other channel on the full CPaaS platform, from the same Celitix account.
Improve your customer experience
Turn broadcasts into conversation. Connect with customers and drive conversions.
Email OTP FAQs
Each code is valid for a configurable window, typically five to ten minutes. Shorter windows are more secure but create more resend requests, so the default is set where most products land after testing both.
Yes. Personalise the HTML template to match your brand, including sender name, logo, colours, and copy. White-label delivery means the customer never sees a Celitix address in the from field.
They request a resend, and the system tracks delivery failures so you can see whether it bounced, was filtered, or was simply never opened. Automatic fallback to SMS or WhatsApp can be enabled on the same flow.
On its own, no channel is. Combined with a second factor it provides solid protection for high-value transactions, which is why the multi-channel fallback matters more than the channel you start with.
Yes. The email OTP API is developer-friendly and integrates in minutes with ready-made templates. The same credentials cover SMS, WhatsApp, and voice verification, so adding a second factor needs no second integration.
Integration usually completes within an hour using the API and the prebuilt templates. Connecting a CRM or adding a second channel as fallback adds a little more, and neither requires a separate account.
Yes. The email verification API India teams use checks that an address is valid and deliverable before a code is sent, which cuts bounces, protects your sender reputation, and blocks a common signup abuse pattern.