Automatically send and verify one-time passwords your customers receive from your system via SMS. Integrate BulkGate OTP API into your system and allow it to validate and protect your customers.


What is SMS OTP?

OTP stands for a one-time password. It is an automatically generated numeric or alphanumeric code sent via SMS that is valid for a short time and only for single login or transaction.

Mobile number verification is highly recommended, especially if your business enables online payments or handles sensitive and important user data.

You can now send One-time passwords via the Viber channel as well.

OTPs are, for example, really beneficial for:

  • E-shops
  • Banks and other financial services
  • Services and systems that have to verify users identity
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How BulkGate SMS OTP works

SMS OTP reception

A user automatically receives, for example, a short 4 digit code sent via SMS OTP API.

Code verification

After the user enters the code into your system, it is automatically verified.

Gaining access

If the code is entered correctly, the user gains access to your system or their account. If entered incorrectly, the OTP API may resend the code.

Why implement BulkGate SMS OTP API

SMS OTP helps protect your business and your customers. One-time passwords are more secure than traditional static passwords your customers generate. OTPs may even replace them for authentication purposes.

SMS OTP API security

Protect your customers

Protect your customers’ identity and data. Unlike weak static passwords that your customers generate themselves and reuse on multiple accounts, which makes them vulnerable to hackers, OTP is invalid within a minute and cannot be used again.

SMS OTP security

Protect your business

SMS OTPs help you protect your business from scammers. OTP API can verify phone numbers to ensure that you will do business or communicate with real customers.

BulkGate SMS OTP API documentation

You can now enable your system or application to automatically send and verify SMS OTP. We provide you with simple API documentation where you can find how to set your system to:

  • Send SMS OTP to your customers
  • Verify the OTP they entered
  • Resend SMS OTP if they need it
SMS OTP API documentation

BulkGate SMS OTP features and benefits


Top priority

Deliver one-time passwords within few seconds with the highest SMS priority.


Simple implementation

Our SMS OTP API is easy to implement into your system or application.


An extra layer of security

One-time passwords are often used as an additional layer of security for your customers. This is so-called two-factor authentication.


Relevant phone numbers

Verify customer phone numbers using OTP. Communicate with real customers through real phone numbers.


Customer satisfaction & credibility

Using SMS OTP increases customer satisfaction, as you take their protection seriously, and in turn, increases the credibility of your business.



Pay only for SMS OTP messages you send. No monthly fees, no contracts. See our price list.

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Pay less for outstanding service

Enjoy sending OTPs worldwide at affordable prices via BulkGate SMS OTP API. You only pay for the messages you send. BulkGate is here for small and big businesses alike.