Back End Developer

PT Solusi Infotech Semesta Indonesia (SIESTA); Kota Bandung; On-site; IDR 167,400,000 - 279,000,000; Full time

Job summary

PT Solusi Infotech Semesta Indonesia (SIESTA) is hiring a Backend Engineer (Golang) to build a core prepaid platform. You will design and implement real-time transaction processing, batch pipelines, and lifecycle services for cards and accounts, operating at national scale alongside a legacy system.

We expect 2+ years of backend experience in Go, strong knowledge of concurrency, RESTful APIs, and robust database transactions.

Qualifications

• 2+ years of professional backend experience with production Go
• Deep understanding of concurrency and high-concurrency transaction engines
• Experience designing and documenting RESTful APIs with versioning

Responsibilities

• Build real-time transaction engine for top-up, purchase, and reconciliation with strict idempotency
• Develop batch processing pipelines for settlement files and journaling
• Implement card and account lifecycle services with state machines
• Create REST APIs and file-based interfaces for enterprise systems
• Ensure observability with structured logging and end-to-end tracing

Skills

Go (Golang)

Concurrency patterns

RESTful APIs

Database transactions

Error handling

Testing

Tools

Docker

Kubernetes

sqlc

PostgreSQL

Job description

Backend Engineer (Golang) — Core Prepaid Platform

*Location:* Bandung, Indonesia & Malang, East Java

*Type:* Full-time

*Domain:* Digital Banking / Payment Systems

*Experience:* Minimum 2+ years

About the Role

We're modernizing a mission-critical *Core Prepaid Platform* for one of Indonesia's largest payment ecosystems — think real-time transaction processing, card lifecycle management, settlement engines, and fraud detection at national scale. This is not a maintenance job. You'll be building the backbone of a next-generation payment host from the ground up, designed to run *in parallel with a legacy system* during a carefully orchestrated coexistence phase.

If the words "atomic balance updates under high concurrency" make your eyes light up — keep reading.

---

What You'll Build

• Real-time transaction engine — top-up, purchase/deduct, reversal, and correction flows with strict idempotency guarantees
• Batch processing pipelines — settlement files, reconciliation, journal generation with checkpoint/restart capabilities
• Card & account lifecycle services — state machines for issuance, activation, block/unblock, replacement, and closure
• Integration layer — REST APIs and file-based interfaces with enterprise middleware, journaling platforms, and security services
• Observability-first services — structured logging, correlation IDs, metrics, and end-to-end traceability baked in from day one

---

Our Stack

• Language: Go (Golang)
• HTTP Framework: Chi / Fiber
• Data Access: sqlc (type-safe, code-generated SQL)
• Database: PostgreSQL (or similar RDBMS)
• Messaging/Queue: Kafka / Redis (nice to have)
• Observability: Structured logging, metrics, distributed tracing
• Infra: Docker, CI/CD, Kubernetes (nice to have)

---

What We're Looking For

Must-Haves

• 2+ years of professional backend experience, with solid hands-on Go in production
• Strong understanding of concurrency patterns in Go: goroutines, channels, mutexes, and worker pools — you'll need this for a high-concurrency transaction engine where balance consistency is non-negotiable
• Familiar with idempotency patterns — duplicate detection, retry-safe APIs, request deduplication, exactly-once semantics
• Deep understanding of database transactions, isolation levels, and locking (no partial postings on your watch)
• Experience designing and documenting RESTful APIs with versioning and backward compatibility in mind
• Comfortable writing clean, testable, well-documented code — unit and integration tests are part of the definition of done
• Solid grasp of error handling, timeouts, retries, and graceful degradation in distributed systems

Nice-to-Haves (Bonus Points)

• Previously involved in banking or financial systems — payments, core banking, e-money, card systems, or settlement engines
• Familiarity with financial transaction flows: payment, settlement, reconciliation, journaling, reversal/correction handling
• Experience with batch/file processing (control totals, duplicate file checks, staging & quarantine patterns)
• Understanding of maker-checker workflows, audit trails, and data masking requirements
• Exposure to PCI-DSS or similar financial security/compliance standards
• Experience with migration/coexistence scenarios — running new systems alongside legacy ones with routing-based rollout

---

What Success Looks Like (First 6 Months)

• You ship transaction services where no retry ever causes a double posting
• Your services survive failure scenario testing — timeouts, dependency outages, failover — with zero lost or duplicated transactions
• Your code passes concurrency and load tests under high TPS with consistent balance outcomes
• Every transaction you process is fully traceable end-to-end via correlation references

---

Why Join Us

• Real scale, real stakes — your code handles actual money movement for millions of users
• Greenfield architecture — no legacy tech-debt hell on your side of the fence; you help define the patterns
• Engineering rigor culture — proper SIT/UAT cycles, failover drills, DR testing, and code reviews that actually matter
• Vendor-neutral mindset — we value engineers who understand why, not just how to use a framework
• Growth path — this platform is built to evolve; there's plenty of room to own bigger pieces

---

We welcome applicants from all backgrounds.

#Golang #BackendEngineer #Fintech #PaymentSystems #TechHiring #BankingTechnology