Senior Software Developer (Open Source, MERN, Node.js & Python, GenAI Assisted)

We’re seeking a self‑starter Senior Consultant who thrives in Lean/Agile environments with ambiguous requirements and is known as a problem solver with an engineering mindset. You’ll design and build modern services and applications using Node.js, Python, and broader MERN technologies (React, Express, MongoDB). You will work directly with enterprise business stakeholders, and you will use GenAI coding assistants (e.g., GitHub Copilot, Claude Code) responsibly to deliver production‑quality software faster—without compromising engineering rigor, security, or maintainability.

• Create clarity from ambiguity: Frame problems quickly, propose pragmatic options, run spikes/experiments, and converge on the simplest solution that works.
• Build robust services & UIs:
  • Back end: REST/GraphQL services, event driven components, data pipelines in Node.js and Python (Express/FastAPI; queues/schedulers where needed).
  • Front end: Modern React apps (hooks, state management) with component libraries/design systems.
  • Data: Schemas and integrations using MongoDB (plus relational DBs where appropriate).
    
• Engineer for reliability: TDD/BDD, contract tests, performance profiling, observability (logs/metrics/traces), secure coding and dependency hygiene.
• Use GenAI effectively & safely: Apply Copilot/Claude Code to accelerate scaffolding, refactoring, tests, and documentation; maintain auditability (prompts/ADRs), verify outputs, and enforce style/security gates.
• Shape architecture: Define service boundaries, API standards, integration patterns, and paved paths/templates for MERN services and Python components.
• Partner with the business: Facilitate discovery sessions, translate objectives into technical deliverables, validate value incrementally, and communicate trade‑offs.
• Lead Lean/Agile delivery: Backlog shaping, story mapping, incremental slicing, “build‑measure‑learn” loops, and continuous improvement.
• Mentor & influence: Review designs/code, coach engineers, and raise the engineering bar across teams and engagements.
• Operate what you build: Own release readiness, deployments, and incident/problem management—biasing toward automation and root‑cause fixes.

Key Outcomes (first 6–12 months)

• Ship value early: Two or more production releases that measurably improve a stakeholder KPI (cycle time, error rate, customer task success).
• Establish paved paths: Reusable templates for MERN services and Python components (tests, security, observability baked‑in) including GenAI usage guidelines.
• Reduce ambiguity debt: Lightweight discovery artefacts (decision records, architecture notes, prompt records) that keep changing requirements actionable.
• Strengthen relationships: Trusted partnerships with enterprise stakeholders through clear communication and reliable delivery.

• Bachelor’s Degree in Computer Science, Software Engineering, or a related field.
• Equivalent work experience will also be considered.

• 8+ years in software engineering with substantial production experience in Node.js and Python.
• MERN stack proficiency:
  • React (hooks, state management, component design systems, testing).
  • Express/Node.js for APIs/services; familiarity with Next.js/NestJS a plus.
  • MongoDB (schema design, indexing, performance considerations) and robust data access patterns.
  • Front end tooling (TypeScript, Webpack/Vite, Jest/Testing Library, Playwright/Cypress).
    
• GenAI‑assisted development (required): Demonstrable history of shipping production software using GitHub Copilot and/or Claude Code (or equivalents) with clear practices for reviewing, testing, and securing AI‑generated code; experience capturing prompt rationale and changes in PRs/ADRs.
• Lean/Agile in ambiguity: Hands‑on delivery where requirements are incomplete; adept at spikes, prototypes, iterative validation, and outcome‑focused planning.
• Systems design: API design, messaging/eventing, data modelling, caching, performance, and security fundamentals (OAuth2/OIDC, secrets management, RBAC).
• Quality & reliability: TDD/BDD, contract/performance testing, observability tooling, and production troubleshooting.
• DevSecOps: CI/CD (GitHub Actions/Azure DevOps/Jenkins), containers (Docker), Infrastructure as Code (Terraform or equivalent), automated pipelines. > Note: Linux experience is not required for this role.
• Stakeholder engagement: Proven record working directly with enterprise business stakeholders—facilitating workshops, clarifying requirements, and aligning delivery to business outcomes.
• Communication & leadership: Clear written/verbal skills; ability to influence, coach, and make sound engineering trade‑offs.

• Cloud experience (AWS/Azure/GCP) with managed runtimes/services (identity, data, messaging) — no preferred provider required.
• Data/ML pipelines: Python data stacks (Pandas), streaming (Kafka), orchestration (Airflow), or analytics integrations.
• Security & compliance: Threat modelling, secure code reviews, dependency/OSS risk management, and governance for GenAI usage.
• Regulated domains: Insurance/financial services or other regulated industries.

At Expleo, we are committed to providing a competitive salary and substantial benefits offering with unique wellbeing, financial and employee recognition programmes.

We pride ourselves on our diverse and inclusive culture and offer a variety of family friendly policies and enhanced leave to help you achieve a healthy work life balance.

By providing significant learning and development opportunities, we encourage individual growth and success throughout your career with us.

• Collaborative working environment – we stand shoulder to shoulder with our clients and our peers through good times and challenges
• We empower all passionate technology loving professionals by allowing them to expand their skills and take part in inspiring projects
• Expleo Academy - enables you to acquire and develop the right skills by delivering a suite of accredited training courses
• Competitive company benefits such as medical and dental insurance, pension, life assurance, employee wellbeing programme, sports and social events, birthday hampers and much more!
• Always working as one team, our people are not afraid to think big and question the status quo.

“We are an equal opportunities employer and welcome applications from all suitably qualified persons regardless of their race, sex, disability, religion/belief, sexual orientation or age”.

At Expleo, we understand that many people experience impostor syndrome throughout their lifetime, please do not let this discourage you from applying for this role. Our Talent Acquisition Team welcomes all CV’s and will consider your application in line with the values, requirements and role competencies.