Backend Engineer at Majoo Indonesia (2021 - 2022)
Mid-level Backend Engineer at a SaaS business management platform for MSMEs, focused on cost calculation systems and performance profiling. [Golang, Kafka].
Majoo Indonesia is a SaaS-based business management platform offering POS (Point of Sale), accounting, inventory, CRM, and employee management solutions for MSMEs.
COGS calculation system
- Designed and developed an automated cost calculation system for COGS (Cost of Goods Sold) using a Golang API and Kafka Pub/Sub.
Cost of goods sold has to be recalculated on every transaction, purchase, or stock adjustment. Running that synchronously in the request path would be expensive, so the work was moved onto Kafka Pub/Sub to let the calculation run asynchronously without blocking user transactions.
The merchant’s sale is recorded and answered straight away. The same API publishes an event, and the COGS worker picks it up on its own pace, so the cost figures catch up without the cashier ever waiting on them.
Performance and profiling
- Implemented Golang Profiling and Prometheus metrics to keep performance optimal and speed up issue resolution, eliminating memory leak issues.
Profiling with pprof is what made the memory leak findable in the first place: reading heap allocations with top and list, watching GC cycles through GODEBUG=gctrace=1, and confirming the fix with load testing before and after. I wrote up the full technique afterwards:
- Profiling Techniques in Golang: memory and CPU profiling, GC analysis, and verifying the result with load tests.
Team contributions
- Acted as a dedicated code reviewer, maintaining code quality standards across the team.
Tech stack
- Golang
- Kafka
- Prometheus, pprof