SMS OTP

SMS OTP API Category

Overview

The SMS OTP (One-Time Password) category provides APIs for implementing secure user verification through mobile phone numbers. These APIs enable applications to send temporary verification codes via SMS and validate user-submitted codes, creating a robust two-factor authentication system that enhances security while maintaining a seamless user experience.

Category Details

Parent Category: Root/SMS
Child Categories: None
APIs in this category: Send OTP, Submit OTP

Key Capabilities

Main Functionality

This category offers a complete SMS-based verification workflow, allowing applications to generate, deliver, and validate one-time passwords for secure user authentication and verification processes.

OTP Generation & Delivery

Generate secure, time-limited verification codes and deliver them instantly to users' mobile devices via SMS messaging.

Code Validation

Verify user-submitted OTP codes against the system-generated codes, with built-in expiration handling and attempt limiting for enhanced security.

Customizable Security Parameters

Configure OTP length, expiration time, retry limits, and cooldown periods to balance security requirements with user experience.

Common Use Cases

Financial Services

E-commerce

Healthcare

Account registration verification for banking and payment applications

Transaction authorization for high-value transfers or purchases

Password reset verification for financial accounts

Integration Considerations

Best Practices

Implement appropriate rate limiting to prevent abuse and SMS flooding

Store OTP verification status rather than the actual OTP code after verification

Include clear instructions in the SMS message about OTP usage and expiration

Implement proper error handling for failed SMS deliveries and invalid verification attempts

Important Limitations

OTP codes have a default expiration time of 10 minutes for security reasons

Maximum 5 OTP requests per phone number within a 24-hour period to prevent abuse

SMS delivery depends on carrier reliability and may experience delays in some regions

Phone numbers must be in E.164 format (+[country code][number]) for reliable delivery

How APIs in this Category Work Together

The SMS OTP APIs work in sequence to create a complete verification workflow. The process begins with identity verification and concludes with access authorization based on successful OTP validation.

Key Integration Patterns:

Send OTP + Submit OTP: The fundamental verification flow where an OTP is sent to a user's phone and then validated when submitted by the user

Send OTP + Rate Limiting Logic: Implement custom cooldown periods between OTP requests to prevent abuse

Submit OTP + Account Activation: Trigger account activation or password reset completion upon successful OTP verification

A typical end-to-end implementation starts with your application requesting an OTP be sent to a user's phone number via the Send OTP API. The user receives the code and enters it in your application, which then calls the Submit OTP API to validate the code. Upon successful validation, your application can proceed with the protected action (account creation, password reset, etc.) with confidence in the user's identity.

The SMS OTP category complements other authentication and communication API categories, providing specialized functionality for phone number verification while integrating with broader security and messaging systems.

Related Categories include:

User Authentication: SMS OTP often serves as a second factor in multi-factor authentication systems, complementing password-based authentication

User Management: OTP verification is frequently used during user registration and account recovery workflows

SMS Messaging: The broader category that includes general-purpose SMS messaging capabilities beyond verification use cases

Security & Compliance: SMS OTP helps meet regulatory requirements for identity verification in regulated industries

SMS OTP verification is particularly valuable when combined with traditional authentication methods to create multi-factor authentication systems. While the User Authentication category provides the primary authentication framework, SMS OTP adds an additional security layer by verifying possession of a specific mobile device. This combination is increasingly required by regulations in financial services, healthcare, and other sensitive applications.

Overview#

Key Capabilities#

Common Use Cases#

Integration Considerations#

How APIs in this Category Work Together#

Related Categories#

Overview

Key Capabilities

Common Use Cases

Integration Considerations

How APIs in this Category Work Together

Related Categories