Principal Software Engineer (Ruby on Rails, AI)

ACG_3784_JOB

Our client, a top-notch FinTech company, is looking for a qualified candidate to join their firm. 

• The role is primarily focused on a Ruby on Rails codebase, where you will deliver product capabilities from concept through production. The broader technology environment also includes selected services developed in Go, and you may contribute to these services when necessary.
  
• A strong security mindset is essential, with particular attention to data privacy, credential management, device security, and the responsible use of corporate systems, tools, and accounts.
  

• Design, develop, maintain, and operate backend capabilities within Ruby on Rails and other core services, applying strong engineering fundamentals while maintaining a pragmatic approach to delivery.
  
• Design and continuously improve RESTful APIs and service boundaries, carefully balancing technical trade-offs, scalability, maintainability, and business requirements.
  
• Develop effective data models, optimize SQL queries, and proactively identify and resolve performance bottlenecks and system inefficiencies.
  
• Architect, deploy, and operate cloud-native applications on AWS, making appropriate use of technologies such as Docker and Kubernetes based on system and business needs.
  
• Strengthen operational excellence by improving logging, monitoring, metrics, tracing, incident response processes, and post-incident learning to continuously improve system reliability.
  

• Own the complete delivery lifecycle, from understanding and defining the problem through solution development, testing, production deployment, and operational readiness.
  
• Work closely with Product, Design, Quality Assurance, DevOps, and other stakeholders to clarify requirements, reduce ambiguity, resolve dependencies, and deliver solutions aligned with business objectives.
  
• Plan and manage production releases, coordinate relevant stakeholders, and continuously improve deployment reliability, efficiency, and speed through effective CI/CD practices.
  

• Establish and demonstrate strong engineering standards for clean, scalable, and maintainable software while promoting a high-quality code review culture across the team.
  
• Improve development confidence and reduce reliance on manual testing by implementing effective automated testing strategies and robust engineering review processes.
  
• Maintain and enhance CI/CD pipelines using modern automation platforms to enable frequent, reliable, and secure software releases.
  
• Ensure that improvements in delivery speed, including the use of AI-assisted development, never compromise security, data privacy, scalability, reliability, or compliance requirements.
  

• Apply AI tools to accelerate software development activities such as requirements exploration, prototyping, code scaffolding, automated test creation, and refactoring.
  
• Critically evaluate AI-generated outputs, identify potential weaknesses or errors, and apply strong human verification practices through testing, peer review, security assessment, and threat modelling.
  
• Improve technical documentation, operational runbooks, logs, and system information so that they can be easily understood and used by both engineering teams and AI-enabled development tools.
  

• At least 5 years of professional software engineering experience, including substantial hands-on experience building, deploying, and operating production-grade web applications.
  
• Strong proficiency in Ruby on Rails is preferred. Candidates with strong software engineering fundamentals and demonstrated ability to quickly become productive within a Rails environment may also be considered.
  
• Solid experience designing, developing, and operating distributed systems, web services, and microservices in production environments.
  
• Strong hands-on experience with AWS and modern cloud-native software development practices.
  
• Deep understanding of relational databases, including data modelling, database design, query optimisation, and SQL performance tuning.
  
• Proven ability to lead technical projects from initial definition through production delivery and coordinate releases across multiple stakeholders.
  
• Strong communication and collaboration skills, with the ability to work effectively across Product, Design, QA, DevOps, and other technical and non-technical functions.
  
• Professional English proficiency suitable for daily collaboration with international teams and stakeholders.
  

• Hands-on experience operating Kubernetes or managed Kubernetes environments in production is highly desirable.
  
• Experience with modern monitoring, observability, and logging platforms is considered an advantage.
  
• Knowledge of message brokers, asynchronous systems, and event-driven architectures is preferred.
  
• Experience integrating Large Language Model APIs into customer-facing products or internal tools, including prompt design, asynchronous workflows, and management of non-deterministic AI outputs, is highly advantageous.
  

• Hybrid working arrangement with 2 days in the office and 3 days working remotely each week.
  
• Flexible working hours, with employees able to start between 8:00 AM and 9:00 AM from Monday to Friday.
  
• Full salary during the probation period.
  
• Statutory Social Insurance, Health Insurance, and Unemployment Insurance provided from the probation period and calculated based on 100% of salary.
  
• Additional private healthcare and personal accident insurance, with extended family coverage available for eligible management-level employees.
  
• 13th-month salary.
  
• Between 16 and 24 paid leave days per year, together with additional leave entitlements.
  
• Additional 5 days of paternity leave.
  
• Annual company trips, quarterly team-building activities, and employee clubs and recreational programs.
  
• Annual health examinations.
  
• Professional working equipment provided, including a high-performance laptop, additional monitor, and other necessary tools.
  

• Clearly defined career development and progression pathways.
  
• Financial support for foreign-language qualifications and internationally recognised technology certifications.
  
• Access to internal and external professional training programs.
  
• Regular soft-skills development workshops and technical seminars.
  
• Monthly and biannual employee recognition programs.
  
• Performance and salary reviews conducted twice annually.