Wala-ICT
S-Space
Pilates & fitness studio SaaS
Backend Engineer · Team of 5 · live at s-space.co.kr
The problem
A live microservices platform needed dependable releases and day-to-day production support.
Architecture
Simplified view, no client internals.
What I delivered
- Maintained and debugged the production AWS environment: VPC with private subnets, ECS Fargate, Multi-AZ RDS, ALB, CloudFront, S3, and Secrets Manager.
- Handled production releases through GitLab CI → ECR → ECS Fargate as main backend maintainer of the auth, user, and center services.
- Built a reconciliation job that recovers payments with lost success callbacks and expires stale pending ones.
- Extended Toss Payments with a head-office merchant flow for B2B orders: idempotent confirmation, cancel and refund, fee and settlement tracking.
- Implemented configurable payroll settlement periods and migrated legacy member data with re-runnable scripts, verified on staging first.
Key decisions
Treat a payment callback as something that can get lost
A success callback is not guaranteed to arrive, so a reconciliation job recovers those payments and expires stale pending ones.
Make data migration re-runnable
Legacy member data moved with scripts that can run again safely, and each run was verified on staging before production.
Stack
Java 17 · ECS Fargate · RDS MySQL · CloudFront