Middle / Senior Backend Engineer

Top 3 reasons to join us

• Go build a great FinTech product
• Go build it on top of the state-of-the-art tech
• Go together with top-of-mind people and team.

Job description

Job Overview
We are an emerging securities firm in Vietnam, growing rapidly with a strong focus on technology, professional trading, and innovation. Our mission is to deliver data-driven and intelligent investment solutions that empower retail, professional, and institutional clients.

We are seeking a Backend Engineer with deep expertise in distributed systems, microservices, and high-throughput transaction processing to join our Business Technology Solution (BTS) team.

Software development at KAFI is moving to an AI-augmented model. We have adopted KAFI AI-DLC — an AI-augmented Development Life Cycle where AI agents draft plans and code, and engineers review, decide, and approve at every gate. All artifacts live in git, every decision is logged. The ideal candidate is comfortable working this way as their primary mode — pairing with AI agents on production code, owning the build lifecycle for the units they ship, and contributing to the workflow itself.

This role reports to the Project Manager / Head of Business Technology Solution and is well-suited for engineers with a strong logical mindset, sharp critical judgment on AI-generated code, and a builder's interest in shaping how a financial-services firm adopts AI in delivery.

Key Responsibilities

• Design and build scalable, event-driven backend systems using microservices architecture, leveraging Kafka, NATS Jetstream, Redis Stream, or similar streaming platforms.
• Pair with AI agents on per-unit code generation — review the agent's file plan before execution, edit when necessary, approve to proceed. Verify generated code line-by-line for architecture boundary violations, missing audit hooks, and hardcoded configuration.
• Apply the AI Review Checklist before every commit: grounded · no secrets · scope respected · reversible · human-decidable.
• Own build instructions and the build lifecycle per unit— verify that declared NFRs and compliance extensions fire correctly in the code you ship.
• Develop and enhance backend services that integrate with core trading systems (equities, derivatives), enabling flexible capabilities such as order management, margin products, and fee logic.
• Build and operate systems capable of handling high transaction volumes (hundreds of thousands per day), ensuring strong scalability, availability, and observability.
• Open Architecture Decision Records (ADRs) when generated code would create a new trade-off the Solution Architect has not accounted for. Surface contradictions with the project knowledge base early.
• Collaborate with Solution Architects, Business Analysts, Project Manager, Product Designers, and DevOps engineers across the AI-DLC workflow — every stage ends in a two-option gate (Request Changes / Continue).
• Contribute to engineering best practices — coding standards, code reviews, role skill files (.claude/skills/kafi/roles/dev.md), starter prompts, and cross-cutting skills (code-review, security-audit, performance-regression).
• Participate in roadmap planning, system reviews, and continuous improvement initiatives to enhance both the trading platform infrastructure and the AI-DLC workflow itself.

Your skills and experience

Must-Have:

• 3+ years of experience in backend software development, with strong proficiency in at least one of: Go, Python, Java or Rust.
• Solid experience building distributed systems, including microservices architectures, event-driven systems, and streaming platforms (Apache Kafka / NATS Jetstream / Redis Stream or equivalent).
• Experience designing and building systems for high-throughput or transaction-intensive environments, with strong understanding of scalability, fault tolerance, performance optimization, and observability.
• Strong knowledge of API design and integration — RESTful services, gRPC, WebSocket, OpenAPI, .proto definitions.
• Experience with relational and NoSQL databases (PostgreSQL primary, plus MongoDB or similar), including data modeling and performance tuning.
• Hands-on experience using AI coding assistants (Claude Code, Cursor, GitHub Copilot, or similar) for meaningful work — with opinions about what works and what does not.
• Critical thinking about AI-generated code — ability to distinguish “looks right” from “is right,” and to catch what the agent missed.
• Effective written communication — much of AI-DLC work happens in markdown plans. Precise writing matters.
• Demonstrated experience in technical leadership, mentoring engineers, conducting code reviews, and contributing to system design decisions.
• Strong analytical and problem-solving skills, with a proactive, ownership-driven mindset.

Nice-to-Have:

• Experience in trading systems, quantitative platforms, fintech, or capital markets.
• Familiarity with low-latency or real-time systems, especially in trading or execution contexts.
• Exposure to securities trading infrastructure such as OMS, market data systems, or trading APIs.
• Experience integrating with core systems in financial services (e.g., core securities, banking systems).
• Hands-on with containerization and orchestration (Docker, Kubernetes), CI/CD pipelines, and observability tooling (Prometheus, Grafana, OpenTelemetry).
• Experience with MCP (Model Context Protocol) servers, Claude Code skills, or other AI agent integration patterns.
• Interest in authoring developer-experience tooling — skills, starter prompts, role guides.
• Prior contribution to an AI-augmented workflow at another company.

Why you'll love working here

• Attractive salary
• Government Social Insurance is based on full of gross salary
• Full salary during probation
• Working Monday – Friday, 8am:5pm
• For every 5 work-years, +2 day to annual leave​​
• Diverse company culture activities: Annual Year End Party, Quarterly party, Company outings, Team building, Coffee and Snack, etc