Senior Full-Stack / AI Engineer (Backend-Focused) – Philippines | Long-Term

About the Opportunity We are a US-based software solutions company looking for highly skilled, independent, and experienced Full-Stack / AI Engineers based in the Philippines for long-term collaboration. We're particularly interested in developers who have strong backend engineering fundamentals, hands-on experience building AI-powered applications, and the ability to understand, maintain, and improve complex existing systems. We're not looking for developers who simply write code based on instructions. We want engineers who can understand the bigger picture, evaluate different technical approaches, make sound architectural decisions, and take ownership of delivering reliable, scalable solutions. We value engineers who are language-agnostic, adaptable, and comfortable leveraging modern AI development tools to accelerate delivery without compromising code quality. What We're Looking For 1. Strong Full-Stack Engineering (Backend-Focused) Solid professional experience developing production-grade full-stack applications, with particular strength in backend architecture and development. Strong understanding of APIs, databases, authentication, security, performance, scalability, and distributed systems. Ability to quickly understand unfamiliar codebases, existing architectures, and business workflows. Experience designing, developing, debugging, refactoring, and maintaining complex applications. Strong understanding of microservices architecture, system integration, and cloud-native development. Ability to independently evaluate architectural trade-offs and make critical technical decisions. Language-agnostic mindset — comfortable adapting to different programming languages, frameworks, and technology stacks. 2. Hands-On AI Engineering Experience (Required) At least 2–3 years of meaningful, hands-on contributions to AI-related projects, preferably in production environments. Experience building and integrating LLM-powered applications into real-world software systems. Strong understanding of prompt engineering, context management, embeddings, vector databases, and semantic search. Experience developing AI-powered workflows, intelligent automation, and backend AI services. Ability to design reliable AI systems with appropriate evaluation, monitoring, error handling, and fallback mechanisms. Experience with offline and/or online AI evaluation frameworks. Ability to explain technical contributions, architectural decisions, and challenges encountered in previous AI projects. A portfolio, GitHub repository, technical demonstration, or case study showcasing actual AI project contributions is a major plus. 3. AI Agents & Agentic Workflow Automation (Big Plus) We're especially interested in candidates with experience in: AI agent development and agentic workflow automation. LangGraph and LangChain. Multi-agent systems and agent orchestration. Tool calling, function calling, and external API integrations. Workflow state management, memory, context management, and task planning. Human-in-the-loop workflows and approval mechanisms. Building reliable, observable, and production-ready agentic applications. 4. AI-Assisted Software Development We strongly value engineers who know how to use modern AI development tools effectively. Experience using tools such as Claude Code, Cursor, GitHub Copilot, Codex, or similar AI coding assistants. Ability to use AI tools for code generation, debugging, refactoring, testing, documentation, and architecture exploration. Strong ability to review, validate, and improve AI-generated code. Comfortable working across different programming languages with AI assistance. Ability to balance development speed with maintainability, security, and engineering best practices. We care more about engineering fundamentals, problem-solving ability, and technical judgment than expertise in one specific programming language. 5. System Architecture & Technical Decision-Making Strong understanding of software architecture and system design principles. Ability to analyze existing systems and identify technical limitations, risks, and opportunities for improvement. Experience comparing architectural approaches and explaining the reasoning behind technical decisions. Familiarity with microservices, event-driven architectures, asynchronous processing, and distributed systems. Ability to make practical decisions considering performance, scalability, cost, maintainability, and delivery timelines. Strong debugging and root-cause analysis skills. 6. Communication & Collaboration Strong written and verbal English communication skills. Comfortable communicating directly with product managers, DevOps engineers, developers, and operational stakeholders. Ability to translate business requirements into practical technical solutions. Able to explain technical trade-offs clearly to both technical and non-technical audiences. Proactive in identifying blockers, raising concerns, and proposing solutions. Comfortable working independently with minimal supervision while maintaining regular communication. Preferred Technical Stack We're interested in experience with the following technologies and concepts. You don't need to know everything listed, but you should have strong fundamentals and be able to learn unfamiliar technologies quickly. Backend & Architecture Python, Node.js, TypeScript, C#, Java, or equivalent backend technologies REST APIs, asynchronous processing, microservices architecture Distributed systems, API integration, authentication, and security AI / LLM Engineering LLM integration and orchestration LangChain, LangGraph Multi-agent systems and agentic workflows Prompt engineering and context management RAG (Retrieval-Augmented Generation) Embeddings, vector stores, and semantic/hybrid search AI evaluation frameworks (offline and online) LLM observability, reliability, and performance optimization Cloud & Infrastructure AWS and/or Microsoft Azure Cloud-native application development AWS RDS or equivalent managed relational databases Docker, CI/CD, and deployment workflows Cloud storage, queues, and serverless services Databases & Search PostgreSQL, MySQL, or other relational databases Vector databases and vector search Full-text, semantic, and hybrid search Data modeling, indexing, and query optimization Nice-to-Have Skills The following experience would be beneficial but is not required: Machine Learning (ML) fundamentals and applied ML development MLOps, model deployment, monitoring, and lifecycle management Data engineering and ETL/ELT pipelines Feature engineering and feature pipelines Model fine-tuning and optimization AI infrastructure and production ML systems Responsibilities Design, build, maintain, and enhance full-stack applications with a strong focus on backend engineering. Contribute to the development of AI-powered products, intelligent automation, and agentic systems. Analyze and understand existing codebases before implementing changes. Make informed architectural decisions and recommend improvements. Integrate LLMs, external APIs, databases, and cloud services. Use AI-assisted development tools to improve engineering productivity. Write maintainable, secure, testable, and production-ready code. Collaborate with product, engineering, DevOps, and operational stakeholders. Troubleshoot complex technical issues and proactively identify solutions. Take ownership of assigned features and deliverables from design through deployment. Minimum Qualifications Strong professional full-stack software development experience, with a backend specialization. At least 2–3 years of meaningful hands-on AI project experience. Proven ability to work with existing codebases and make sound architectural decisions. Practical experience integrating LLMs or building AI-powered applications. Proficiency with modern AI-assisted coding tools. Strong software engineering fundamentals, regardless of programming language. Excellent problem-solving and communication skills. Ability to work independently and take ownership of technical deliverables. Based in the Philippines and interested in long-term remote collaboration. How to Apply Please provide the following information in your Upwork proposal: Professional Background: Briefly introduce yourself and describe your full-stack and backend engineering experience. AI Project Experience: Describe your AI-related projects from the past 2–3 years, including your specific technical contributions. Technical Stack: List your strongest programming languages, frameworks, cloud platforms, and AI technologies. AI Development Tools: Which AI coding assistants do you regularly use, and how do you incorporate them into your development workflow? Portfolio / GitHub: Share relevant GitHub repositories, project portfolios, case studies, or live applications, particularly AI-related projects. Availability: How many hours per week are you available, and when can you start? Hourly Rate: What is your expected hourly rate in USD? Engagement Type: Are you an individual freelancer or part of a development team/agency? Loom Video Introduction (Required) Please include a Loom video link (approximately 3–5 minutes) with your application. We'd like to learn more about your technical background and how you approach engineering challenges. Please cover the following in your video: Introduction: Briefly introduce yourself and your professional experience. Recent AI Project: Walk us through one AI project you've worked on recently. Explain what it does, the architecture, technologies used, and your personal contributions. Technical Decision-Making: Share an example of a challenging architectural decision you made and why you chose that approach. AI-Assisted Development: Explain which AI coding tools you use and how they help you develop software. Communication: Briefly describe how you collaborate with product, DevOps, and other stakeholders. Screen sharing, architecture diagrams, or project demonstrations are highly encouraged, especially if you have an AI application you can showcase. Please avoid sharing confidential client information or proprietary code. Make sure your Loom video link is publicly viewable or accessible without requesting additional permissions. We will prioritize applications that include a relevant technical portfolio, clear AI project experience, and a Loom video demonstrating strong engineering fundamentals. What We Offer Long-term opportunities with a US-based software solutions company. Interesting software engineering and AI development projects. Fully remote collaboration. Flexible working arrangements with agreed communication and delivery expectations. Competitive compensation based on experience and technical capabilities. Opportunities to work with modern AI tools, architectures, and technologies. A collaborative environment that values ownership, technical judgment, and continuous improvement. We're looking for engineers who can do more than implement features — people who can understand systems, solve difficult problems, make good technical decisions, and help us build high-quality software. If you're a strong backend-focused full-stack engineer with real AI project experience, we'd love to hear from you!