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ProjectJan 2024 - Present

Middleware Service

Built middleware flows for Thailand/Vietnam SMS OTP and Email OTP, supporting secure authentication and payroll authorization through reliable backend-to-backend transactions.

Problem

Authentication and payroll authorization flows needed a reliable middleware layer to coordinate external OTP providers and backend-to-backend verification across different country channels.

  • OTP delivery had to work across Thailand SMS, Vietnam SMS, and email-based verification paths
  • Authentication and payroll authorization could not depend on fragile one-off integrations
  • Middleware had to handle external service communication without breaking core business flows
Solution

Built middleware integrations that handled OTP delivery and verification for multiple channels while supporting secure backend-to-backend transaction flows.

  • Integrated Thailand and Vietnam SMS OTP providers
  • Added Email OTP support for secure verification scenarios
  • Implemented transaction handling between internal services and external providers for authentication and payroll-related approvals
Decisions

Made backend decisions that favored reliability, provider separation, and safer transaction handling across verification flows.

  • Kept provider-specific integration behavior isolated instead of mixing all OTP paths into one fragile flow
  • Structured backend-to-backend communication so verification outcomes could be handled more predictably
  • Focused the middleware layer on secure orchestration rather than pushing external-provider complexity into product modules
Trade-offs

Accepted integration complexity in exchange for broader channel support and stronger operational reliability.

  • Multiple OTP channels increased maintenance scope but improved real-world coverage
  • Middleware orchestration added an extra backend layer but reduced duplication across consuming services
  • External provider handling required more defensive backend logic to account for variable delivery behavior
Impact

The middleware layer improved verification reliability for security-sensitive flows and made OTP-based business operations easier to support across multiple channels.

  • Expanded OTP support across SMS and email verification paths
  • Improved the reliability of authentication and payroll authorization workflows
  • Reduced the need for product modules to manage provider-specific verification behavior directly