Senior Fullstack Software Engineer

KMS Technology

About The Position

KMS is seeking a Senior Fullstack Engineer to design, develop, and maintain scalable healthcare applications and services. The role combines modern frontend development with backend services and system integrations, with an emphasis on performance, security, and reliability. The engineer will use React, TypeScript, JavaScript, Node.js, NestJS, and Medplum to help build healthcare solutions that improve clinical workflows and user experiences. The role involves working with cross-functional teams on business requirements, technical specifications, and healthcare workflows. The engineer owns assigned features across the software development lifecycle, from design and implementation through testing and delivery, and contributes to quality through code reviews, documentation, testing, and use of AI-assisted development tools. This position is based with KMS Mexico; the posting lists Mexican-law benefits.

Requirements

At least 8 years of professional software development experience, including strong hands-on fullstack web application development.
Advanced proficiency in React, TypeScript, JavaScript (ES6+), HTML5, and CSS3.
Strong hands-on experience developing backend applications and RESTful APIs using Node.js, NestJS, and TypeScript.
Experience designing and implementing single-page applications, reusable components, custom hooks, and modular frontend architectures.
Strong experience building, consuming, and integrating RESTful APIs, including asynchronous operations and error handling.
Practical experience integrating LLM APIs, tool calling, or agentic AI workflows into software applications.
Experience with Spec-Driven Development or AI-driven software development lifecycle practices.
Experience implementing authentication, authorization, and secure application development practices.
Strong understanding of software architecture, design patterns, and clean coding principles.
Experience with automated testing using Jest, React Testing Library, or similar frameworks.
Experience developing responsive and accessible web applications, including familiarity with WCAG guidelines.
Experience with Git, GitHub, CI/CD pipelines, and code review processes.
Familiarity with AI-assisted development tools such as Claude Code, GitHub Copilot, or Cursor.
Strong analytical, troubleshooting, and problem-solving skills.
Ability to work independently, own technical deliverables, and adapt to changing requirements.
Excellent written and verbal English communication skills, including experience collaborating with cross-functional and international teams.
Experience working in Agile/Scrum development environments.

Nice To Haves

Experience developing applications for the healthcare industry or other regulated environments.
Familiarity with healthcare interoperability standards such as HL7 FHIR.
Experience with Medplum or similar healthcare platforms for clinical data and electronic health records.
Understanding of healthcare data privacy and security requirements, including HIPAA and protection of Protected Health Information.
Experience with backend development using Python or other server-side technologies.
Experience using Figma to implement UI designs and collaborate with design teams.

Responsibilities

Design, develop, and maintain scalable web applications using React, TypeScript, and JavaScript.
Design, develop, and maintain scalable backend services and RESTful APIs using Node.js and NestJS.
Develop reusable frontend components, custom hooks, and modular application architectures.
Design, develop, and integrate RESTful APIs with internal and third-party systems.
Implement authentication, authorization, and role-based access control to secure application functionality and sensitive data.
Build responsive, accessible, user-friendly interfaces based on UI/UX designs and accessibility best practices.
Collaborate with cross-functional teams on business requirements, technical specifications, and healthcare workflows.
Write and maintain unit and integration tests.
Participate in code reviews and promote clean coding standards.
Troubleshoot application issues, identify root causes, and implement maintainable solutions.
Protect sensitive healthcare information in application code, logs, integrations, and error-handling processes.
Own assigned features throughout the software development lifecycle, from technical design and implementation to testing and delivery.
Create and maintain technical documentation for application components, APIs, and integrations.
Use AI-assisted development tools to improve coding efficiency, code quality, and workflows.
Participate in Agile ceremonies, communicate progress, and proactively identify and escalate technical risks or blockers.

Benefits

Mexican-law benefits.
15 days of PTO in year zero; from the first year onward, PTO increases by 3 days per year.
Five days of leave for the death of immediate family members, negotiable.
Major Medical Expenses Insurance covering immediate dependents (spouse and children).
Annual performance bonus of approximately 10% of annualized salary.
Annual salary adjustment.
Employee Referral Bonus.
Paid certifications and courses.
Coursera license.
5% Savings Fund.
5% Grocery Vouchers.