Principal Application Engineer

mongodb

Contract type

Ongoing

Work mode

Remote · France

Experience

Senior · 8+ years

Job description

A senior software developer role on MongoDB's Application Modernization Platform (AMP), migrating enterprise customers' legacy relational Java applications to modern cloud-based architectures running on MongoDB, using GenAI and algorithmic tooling to accelerate delivery. The role is based remotely in France.

At a glance

Work mode: Remote · France
Languages: French – fluent, English

What you'll do

Work as a software developer in an Agile environment delivering solutions for customers focused on migrating legacy relational-based Java applications to a more modern cloud-based architecture running on MongoDB, leveraging GenAI tools and approaches to accelerate the process
Innovate on potential new GenAI-based solutions for specific challenges in addition to applying existing playbooks and tooling for migration
Shape architecture and technology strategy across AMP modernization projects and workstreams, making complex technical decisions with limited supervision and connecting engineering choices to customer and business outcomes
Lead the assessment and modernization of legacy Java applications by uncovering dependencies, embedded business logic, integration points, and operational constraints; recommend fit-for-purpose modernization paths rather than defaulting to lift-and-shift
Design, implement, and review production-quality solutions using Java and Spring Boot, including APIs, integrations, monolith decomposition, relational-to-document data modeling, stored-procedure transformation, schema evolution, and MongoDB operational practices
Establish safe, incremental delivery practices through explicit acceptance criteria, automated testing, CI/CD, observability, and rollback, dual-run, or other risk-control strategies; identify quality, security, performance, and reliability risks and guide teams to resolve them
Serve as a senior technical partner to customers, application owners, and account and project stakeholders by explaining complex topics clearly, aligning priorities, navigating disagreement, communicating trade-offs, and maintaining trust through high-risk change
Multiply the effectiveness of engineers by mentoring, raising engineering standards, creating reusable migration playbooks and documentation, applying GenAI advancements responsibly where valuable, and influencing project direction without relying on formal authority

What we're looking for

Professional fluency in French is required
Bachelor's degree in Computer Science, Information Technology, or a related field, or equivalent practical experience
Typically 8+ years of progressive experience designing, building, and delivering Java applications, including significant experience leading complex application modernization initiatives
Expert understanding of Java fundamentals, object-oriented design, concurrency, error handling, performance considerations, and maintainable software architecture; able to review code and guide design decisions across teams
Deep production experience with Spring Boot and related patterns for building resilient services, APIs, integrations, and testable distributed applications
Demonstrated ability to assess legacy estates, decompose monoliths, uncover dependencies and embedded business logic, and define practical modernization strategies with clear trade-offs
Strong experience with relational databases and SQL, including stored procedures, data dependencies, data migration, schema evolution, and relational-to-document modeling for MongoDB or comparable document databases
Proven history of delivering high-cadence modern applications using Agile methodologies, test-first development, CI/CD pipelines, Git-based version control, observability, and reliability practices; demonstrated success mentoring engineers and influencing technical outcomes across teams

Nice to have

Experience in building REST APIs with Spring Boot
Experience in performance and memory optimization of JAVA applications
Familiarity with tools like Postman, IntelliJ IDEA, and Maven/Gradle
Exposure to other languages or technologies like JavaScript, .Net
Understanding of ORM tools like Hibernate, Spring Data or JPA (even through coursework or self-study)
Experience in nascent GenAI technologies and approaches, such as using OpenAI/Anthropic API not purely through chat interfaces
Experience with AI-powered development tools like Claude Code, Cursor, or similar code assistants
Good experience of using MongoDB

Your team

Application Modernization Platform (AMP)

A MongoDB offering that modernises customers' legacy relational applications to a modern architecture underpinned by MongoDB using a combination of software, processes, and engineers; works with enterprise-grade customers in all verticals.

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About MongoDB

Built for change

MongoDB's unified data platform, the most widely available, globally distributed data platform on the market, helps organizations modernize legacy workloads, embrace innovation, and unleash AI. Its cloud-native platform, MongoDB Atlas, is the only globally distributed, multi-cloud data platform and is available across AWS, Google Cloud, and Microsoft Azure.

Key facts

Data platform / software
Over 67,000 customers
Approximately 75% of the Fortune 100 rely on MongoDB
Offices worldwide
MongoDB Atlas available across AWS, Google Cloud, and Microsoft Azure

Partners & customers

AWSGoogle CloudMicrosoft Azure

What they value

Leadership Commitment