Fullstack Developer, .NET

Nextlane

Fullstack Developer building .NET and React/Next applications for Nextlane’s automotive retail software platform. Leading architecture, delivery, testing, modernization, and engineer mentorship.

Posted 8/10/2026full-timeMadrid • 🇪🇸 SpainMid-LevelSeniorWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates expertise in .Net and React/Next for building scalable applications, with a strong focus on software engineering fundamentals, architectural decision-making, and mentoring within cross-functional teams. Proven ability to enhance engineering practices and ensure high-quality, maintainable solutions.

Highest-signal resume keywords

4-5+ Years ExperienceStrong Software Engineering FundamentalsBackend Development with .NetFrontend Development with React/NextCI/CD Pipeline Experience

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

.NetReactNextArchitectural Decision-MakingAutomated Testing StrategiesCode ArchitectureSOLID PrinciplesPerformance OptimizationGit-based Development WorkflowsAsynchronous Programming

Soft Skills

Strong Communication SkillsProblem-Solving SkillsMentoring EngineersCollaboration within Cross-Functional TeamsAbility to Navigate Ambiguity

Tools & Technologies

CI/CD PipelinesAutomated DeploymentsMobile Release ProcessesAnalytics SolutionsPerformance Monitoring

Industry Keywords

Software Engineering Best PracticesCode QualityMaintainabilitySecurityObservability

Tech Stack

Tools & technologies

React

About the role

Key responsibilities & impact

Own the design, development, and delivery of complex features and systems across applications
Build scalable, maintainable, and high-quality solutions using .Net and React/Next
Drive technical decisions balancing business needs, delivery timelines, performance, and maintainability
Contribute to backend and frontend architecture, development practices, and engineering standards
Collaborate with Product, Design, and Engineering teams
Lead complex functionalities and ensure applications remain reliable, secure, and performant
Define and improve testing, release, and quality practices
Identify technical risks and propose solutions supporting future growth
Lead refactoring and modernization initiatives
Mentor engineers through technical guidance, code reviews, and knowledge sharing
Act as a technical leader driving engineering excellence and raising the quality of the mobile platform

Requirements

What you’ll need

4-5+ years of experience
English B2/C1
Spanish
Strong communication skills, verbal and written
Strong software engineering fundamentals, including architecture, design patterns, testing, and system design
Ability to deliver complex features with ownership and autonomy
Experience making architectural decisions and evaluating technical trade-offs
Strong problem-solving skills and ability to navigate ambiguity in complex systems
Experience improving engineering practices and development processes
Experience mentoring engineers and collaborating within cross-functional teams
Strong professional experience developing backend services with .Net
Good experience developing frontend applications with React/Next
Proven experience building, maintaining, and scaling production applications
Understanding of code architecture, design patterns, state management, asynchronous programming, and performance optimization
Understanding of clean architecture and SOLID principles
Experience implementing automated testing strategies, including unit, integration, and UI tests
Strong experience with CI/CD pipelines, automated deployments, and mobile release processes
Understanding of software engineering best practices, including code quality, maintainability, security, and observability
Experience with Git-based development workflows and collaborative engineering practices
Familiarity with analytics, performance monitoring, and feature flagging solutions
Ability to evaluate technical trade-offs and contribute to architectural decisions across the mobile platform

Benefits

Comp & perks

Remote Work: Up to 3 days a week
Flexible entrance and departure time
Summer schedule on Fridays
Referral Bonus: €1500 for every talent you refer (after 6 months)
Flexible Remuneration: COBEE platform
Private Medical Insurance: Adeslas
Continuous Learning: Access to our internal platform for continuous development
Vacation: 23 vacation days plus an intensive schedule in July and August
Teambuilding: Our afterworks and activities are memorable!