Ratthatummanoon Kosasang

About

Software Engineer with expertise in backend development, distributed systems, and cloud infrastructure. Proficient in designing event-driven systems utilizing modern programming languages and cloud technologies.

Experience

1. Backend & Cloud Engineer
   Optimile - Project
   2025-06 — 2025-12

   - Designed a polyglot microservices architecture using Go (Gin) for the API Gateway and Node.js (Express) for business logic, separating request routing from service responsibilities. - Built an event-driven data pipeline using Apache Kafka for asynchronous messaging, MongoDB for persistent storage, and Redis for caching to reduce direct service dependencies. - Containerized Go, Node.js, and Python ML services with Docker Compose, and automated environment setup and service lifecycle management using Shell scripts. - Provisioned AWS infrastructure using CloudFormation (IaC) and integrated Prometheus and Grafana to monitor service health and system performance.

2. Backend Engineer
   MissionProgress-Service - Project
   2026-01 — 2026-05

   - Built an event-driven service to orchestrate emergency response workflows, handling concurrent state transitions across distributed services. - Chose DynamoDB over relational storage to support concurrent event workloads, selecting a provisioned capacity mode suited to write-heavy access patterns. - Implemented a Transactional Outbox pattern (DynamoDB + EventBridge) instead of distributed locks, to keep state transitions atomic without cross-service coordination overhead. - Used Conditional Expressions and Idempotency Keys with SQS-buffered SNS to handle race conditions and duplicate processing under concurrent workloads.

3. DevOps Engineer
   KPS-Enterprise - Project
   2026-01 — 2026-05

   - Set up a self-hosted IaC pipeline using Terraform to reduce manual provisioning and configuration drift across AWS environments (VPC, EC2, IAM). - Built a CI/CD pipeline (Woodpecker CI, Jenkins, Docker Buildx caching) to standardize artifact builds and reduce unnecessary build steps. - Integrated shift-left security scanning (SonarQube, OWASP Dependency-Check, Trivy) into the pipeline so vulnerabilities get caught before code reaches the registry. - Deployed containerized services on Kubernetes, configured for container orchestration, scaling, and service discovery.

4. Software Engineer
   dezo - Project
   2026-03 — 2026-05

   - Built a policy execution engine in Rust to check actions against security rules before they're allowed to run. - Used an AST-based evaluator with strict evaluation boundaries instead of runtime interpretation, to restrict side effects from sandboxed execution. - Added structured audit logging for state transition so issues can be traced after the fact. - Built a monitoring layer that detects failed executions and supports automated recovery without impacting the surrounding execution environment.

5. Software Engineer
   Zeno - Project
   2026-05 — 2026-06

   - Built a code repair engine in Rust that uses Monte Carlo Tree Search instead of rule-based heuristics, since MCTS provides a search strategy for exploring non-deterministic code mutation paths. - Designed a symbol resolution pipeline with a multi-stage clarification step to address incorrect fixes caused by inconsistent code context during large-scale refactoring. - Added a "Testplan Gate" that runs regression suites against every proposed patch before it's accepted, to catch fixes that pass locally but break other tests. - Validated fix correctness against a regression test suite, iterating on the search strategy based on recurring failure patterns.

Education

1. Thammasat University
   Bachelor of Science · Computer Science
   2023-08 — 2027-05

Skills

Role preferences

Open to roles

Software Engineer, DevOps Engineer, DevOps