Backend Developer

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 | Layer | Tech | | *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 --- 📬 How to Apply Send your CV/resume (and optionally your GitHub/portfolio) to developer@siesta.id with the subject: > Backend Engineer (Go) — [Your Name] *Shortlisted candidates will go through:* 1. 📋 CV screening 2. 💻 Technical assessment (Go concurrency + system design — yes, we'll ask about idempotency 😉) 3. 🗣️ Technical interview 4. 🤝 Culture fit & final interview --- We welcome applicants from all backgrounds. If you don't tick every box but believe you can handle high-concurrency financial systems — apply anyway. --- #Golang #BackendEngineer #Fintech #PaymentSystems #TechHiring #BankingTechnology