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vũ hoàng

@vuhoang

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Senior software engineer focused on authorization/authentication and highly-scalable distributed systems performance.

Vietnam

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What I'm looking for

I want to build high-scale backend systems where I can optimize performance and reliability, design secure authorization flows, and strengthen observability. I’m excited by teams that value measurable SLAs, pragmatic architecture, and continuous improvement.

I’m a senior software engineer with 5 years of experience building authorization/authentication systems and highly-scalable distributed architectures. I’m specialized in Ruby-based services with a strong performance-optimization and observability mindset, from design through rollout.

At Ascenda Loyalty, I led end-to-end performance optimization for high-volume transaction processing, cutting time to process 10M transactions from 40 hours to 4 hours. I designed webhook authorization using OAuth2 client credentials with client assertion, standardized Ruby performance/resource tuning for Puma concurrency and pod sizing, and implemented reliability improvements like self-recovery for transient failures and safe automated retries.

I’ve also driven availability and user-impact work—building a 99.99% availability roadmap for a Tier-1 API and improving file processing flow performance by 14x. Earlier, I delivered major SSO integration work (including a backward-compatible rollout) and built foundational platform capabilities such as centralized idempotency, Kafka adoption, and security features like encryption-at-rest for PII.

Experience

Work history, roles, and key accomplishments

Current

Senior Software Engineer (Core Arch)

Current

Ascenda Loyalty

Jul 2025 - Present (11 months)

Led end-to-end performance optimization for high-volume transaction processing, reducing processing time for 10M transactions from 40 hours to 4 hours. Designed authorization and reliability improvements, including OAuth2 client-credentials webhook authorization flow and self-recovery mechanisms that enabled safe automated retries.

Ruby PostgreSQL Redis Kafka OAUTH2 Puma Concurrency Tuning Distributed Systems Performance Optimization Observability

Software Engineer - Auth & Orchestration

Ascenda Loyalty

Jul 2023 - Jun 2025 (1 year 11 months)

Drove end-to-end SSO integration delivery for Australia’s second-largest bank, leading authorization flow design and a backward-compatible rollout that contributed to a 70% increase in redemptions. Built core backend SSO capabilities and implemented a centralized idempotency library to prevent duplicate resource creation from retried requests.

SSO Distributed Locking Rollout Ruby on Rails Observability

Software Engineer - Auth & Integrations

Ascenda Loyalty

Feb 2022 - Jun 2023 (1 year 4 months)

Led company-wide adoption and rollout of Kafka for event streaming, enabling order guarantee and strong eventual consistency while reducing operational/architectural complexity. Built authentication and security features including magic-link passwordless login, a fraud rules engine with MFA triggers, and an application-layer encryption-at-rest approach for PII.

Kafka Application Layer Encryption Ruby Distributed Systems