Senior Application Developer We are looking for a Senior Fullstack Application Developer to define, design, and deliver scalable, sustainable, and secure web applications at the core of the organization. You will own features end to end: modern React frontends, robust PHP (Symfony) and Node.js / TypeScript backends, and cloud-native infrastructure on AWS, from containerized services on Kubernetes (EKS) to serverless workloads on Lambda. A growing part of the role is building with Generative AI: integrating frontier models such as OpenAI GPT, Anthropic Claude, Google Gemini (via Vertex AI), Amazon Bedrock models, and open-weight models such as DeepSeek, and using Claude Code and agentic tooling to plan, build, review, and test software. Idóneo candidates are proactive engineers who are comfortable making architecture decisions across the stack, modernizing legacy systems, and collaborating closely with product, QA, and business teams in a fast-paced, highly communicative, innovation-driven environment. What You Will Do
• Build modern, responsive web interfaces using React, Next.js, TypeScript, JavaScript and Vite.
• Translate complex UI/UX designs into clean, accessible, responsive code.
• Design and develop scalable and secure backend APIs using PHP (Symfony) and Node.js / TypeScript.
• Architect, deploy and maintain containerized services on AWS EKS and serverless applications using Lambda, API Gateway, SQS/SNS, EventBridge, Step Functions and DynamoDB.
• Integrate third-party services and GenAI APIs (streaming responses, RAG, agents, MCP) for intelligent application behavior.
• Work with the PM to provide estimates for technical activities; analyze requirements and document architectural recommendations, systems and code-level design.




• Write unit, integration and functional tests; automate regression and integration tests using AI; maintain high code coverage and code quality.
• Perform code reviews for standards, quality assurance and security (static analysis, container scanning, AI-assisted PR review).
• Implement website optimizations: front-end performance, CDN usage, caching strategies and efficient media handling.
• Modernize legacy components (framework upgrades, migrating server-rendered views to React, moving pipelines to GitHub Actions).
• Address day-to-day and longer-term technical issues and participate in R&D; to evaluate new technologies, solutions and software.
• Mentor junior team members and contribute your skills wherever required. Key Skills, Knowledge & Professional Experience
• Over 5 years of experience in web development, with proven delivery of highly performant, scalable stacks – frontend and backend.
• Experience planning, debugging and writing code with Claude Code (skills, plugins, sub-agents, MCP) and other agentic coding tools.
• Skills to design software end to end (DB structure, components, API, integrations).
• Strong understanding of distributed systems, event-driven architecture and API design (REST, OpenAPI).
• Solid experience with PHP / Symfony and Node.js / TypeScript.




• Strong experience with React and modern JavaScript / TypeScript.
• Hands-on experience with AWS (containers and serverless).
• Experience with LLMs (agents, embeddings, MCP, RAG, APIs of frontier LLMs).
• Development best practices, including unit testing, code reviews and design patterns.
• Experience mentoring junior team members; good communication skills.
• Mindset of an engineer (attention to application performance, security, debugging skills). Technical Skills Languages & Frameworks – Frontend:
• JavaScript, TypeScript, React, Next.js, React Native, Vite, HTML5, CSS3 (SASS/SCSS)
• Redux Toolkit, TanStack Query, React Router, Material UI (MUI) Languages & Frameworks – Backend:
• PHP, Symfony, API Platform, Doctrine ORM, OpenAPI
• Node.js, TypeScript, Express, AWS SDK Cloud & DevOps:
• AWS: EKS, Lambda, API Gateway, Cognito, S3, CloudFront, SQS, SNS, EventBridge, Step Functions, DynamoDB, RDS, CloudWatch
• Infrastructure as Code: AWS SAM / CloudFormation, Serverless Framework, AWS CDK
• Containers: Docker, Kubernetes
• CI/CD & quality: GitHub Actions, SonarQube, New Relic Databases:
• MySQL, PostgreSQL, DynamoDB, Redis, OpenSearch Testing:
• PHPUnit, Jest, Vitest, Testing Library, Playwright Tooling:
• Git, GitHub, NPM / Yarn, Composer, Webpack, ESLint, Prettier
• AI-assisted development: Claude Code, MCP, agents, agentic coding CLI tools, AI PR review GenAI Ecosystem:
• OpenAI GPT, Anthropic Claude, Google Gemini (Vertex AI), Amazon Bedrock, open-weight models (DeepSeek, Llama)
• Embeddings, RAG, vector stores, prompt engineering, tool use / function calling, streaming

📌 Senior Application Developer (México)
🏢 Psl Group
📍 México