Senior Software Engineer C# - Flexible Working

About Xebia For more than 25 years, our global network of passionate technologists and pioneering craftspeople has delivered cutting-edge technology and game-changing consulting to companies on the brink of AI driven digital transformation.Since ****, we have grown into a full service digital consulting company with ****+ professionals working on a worldwide ambition.Driven by the desire to make a difference, we keep innovating.Fuelling the growth of our company with our knowledge worker culture.When teaming up with Xebia, expect in-depth expertise based on an authentic, value-led, and high quality way of working that inspires all we do.At Xebia, we put 'People First'-committed to attracting diverse talent and fostering an inclusive, respectful workplace where everyone is valued for their contributions.We welcome all individuals and evaluate solely on the quality of their work and teamwork.Senior Software EngineerTime Tracking Platform * Greenfield * AI-First DevelopmentAbout the ProjectBuilding a best-in-class time tracking platform from the ground up.This is a greenfield opportunity - no legacy constraints, no technical debt - The platform will integrate natively with the tools our customers already live in.AI-first engineering team.Leveraging AI coding assistants, LLM-augmented workflows, and intelligent automation as a natural part of how you build - not as an afterthought.The system will be used by approximately 3,000 usersThe platform will:Track individual time entries aligned to mapping them under Capex and Opex categoryAssociate time entries with projects and token usageIntegrate with existing tools such as Linear, Airtable, and SlackLeverage bots/agents to provide intelligent suggestions based on calendars, activity, and messaging patternsBe delivered as a greenfield solution, with no migration dependency on legacy systemsRole OverviewAs a Senior Software Engineer on this team, you will own the design and delivery of core backend services, drive integration architecture with third-party platforms, and help establish the engineering patterns.You will work closely with product, design, and customer-facing teams to ensure what gets built solves real problems elegantly.Key ResponsibilitiesPlatform & Backend EngineeringDesign and build scalable, highly available Java microservices on AWS from scratchDefine and own the data model for time tracking entities - entries, projects, users, billing cyclesArchitect RESTful and event-driven APIs consumed by web, mobile, and third-party clientsOwn the full AWS infrastructure for your services: Lambda, ECS/EKS, RDS/Aurora, SQS, S3, CloudWatchImplement CI/CD pipelines using GitHub Actions or AWS Code Pipeline, with automated testing gatesIntegrationsBuild bi-directional sync between the time tracking platform and Airtable bases via the Airtable APIIntegrate with Linear to link time entries to issues, projects, and cycles - keeping both systems in syncDevelop Slack workflows: slash commands, interactive modals, notifications, and Bolt-based event subscriptionsDesign an integration framework that can onboard new third-party connectors without re-architecting core servicesHandle webhooks, OAuth 2.0 flows, token management, and rate limiting for all external platformsAI-First DevelopmentUse AI coding assistants (e.g. GitHub Copilot, Claude, Cursor) as a core productivity tool throughout developmentImplement AI-powered features: intelligent time entry suggestions, anomaly detection, natural language querying of time dataLeverage LLMs for smart auto-categorization of time entries based on calendar, Linear activity, or Slack contextContribute to prompt engineering, RAG pipelines, or fine-tuning workflows as the product roadmap evolvesEvaluate and recommend AI/ML services (AWS Bedrock, SageMaker, OpenAI, Anthropic APIs) appropriate to each use caseQuality & CollaborationWrite clean, well-tested Java code - unit, integration, and contract tests are non-negotiableParticipate in architecture reviews, PR reviews, and cross-functional planning sessionsContribute to runbooks, ADRs (Architecture Decision Records), and internal documentationRequired QualificationsCore (Must-Have)~5+ years of professional software engineering experience~ Backend: Strong Java proficiency~ Spring Boot or Quarkus for microservices; experience with reactive frameworks (Vert.x, WebFlux) a plus~ Cloud: Deep AWS expertise~ Hands-on experience with Lambda, ECS or EKS, RDS/Aurora, SQS/SNS, API Gateway, IAM, CloudFormation or CDK~ APIs: REST API and event-driven architecture design and implementation~ OAuth 2.0, webhook design, idempotency, and third-party API integration patterns~ AI Tooling: Demonstrable AI-first mindset~ Regular use of AI coding tools and willingness to bring LLM-powered features into production~ Greenfield: Proven ability to contribute meaningfully on a greenfield project - from blank canvas to productionIntegration Experience (Highly Desirable)Airtable API - reading/writing records, managing bases, handling webhooksLinear API or GraphQL-based project management tool integrationsSlack Bolt SDK - building apps, slash commands, modals, interactive componentsExperience building a reusable integration or connector frameworkAI / ML (Desirable)Working knowledge of LLM APIs (OpenAI, Anthropic, AWS Bedrock)Experience with prompt engineering, RAG, or embeddings in a production contextFamiliarity with AWS SageMaker or similar ML deployment pipelinesUnderstanding of responsible AI practices - latency, cost, hallucination mitigationNice to HaveExperience in the time tracking, workforce management, or project management SaaS domainFrontend exposure - React or TypeScript - to collaborate closely with full-stack requirementsFamiliarity with multi-tenancy patterns and SaaS billing / subscription modelsContributions to open-source projects or public technical writingExperience with observability tooling: Datadog, Open Telemetry, AWS X-RayEngagement DetailsDuration: ~6 monthsTime zone: East Coast alignment requiredWork style: Highly collaborative, execution-focused, minimal bureaucracy

Core (Must-Have) ~5+ years of professional software engineering experience ~ Backend: Strong Java proficiency ~ Spring Boot or Quarkus for microservices; experience with reactive frameworks (Vert.x, WebFlux) a plus ~ Cloud: Deep AWS expertise ~ Hands-on experience with Lambda, ECS or EKS, RDS/Aurora, SQS/SNS, API Gateway, IAM, CloudFormation or CDK ~ APIs: REST API and event-driven architecture design and implementation ~ OAuth 2.0, webhook design, idempotency, and third-party API integration patterns ~ AI Tooling: Demonstrable AI-first mindset ~ Regular use of AI coding tools and willingness to bring LLM-powered features into production ~ Greenfield: Proven ability to contribute meaningfully on a greenfield project - from blank canvas to production Integration Experience (Highly Desirable) Airtable API - reading/writing records, managing bases, handling webhooks Linear API or GraphQL-based project management tool integrations Slack Bolt SDK - building apps, slash commands, modals, interactive components Experience building a reusable integration or connector framework AI / ML (Desirable) Working knowledge of LLM APIs (OpenAI, Anthropic, AWS Bedrock) Experience with prompt engineering, RAG, or embeddings in a production context Familiarity with AWS SageMaker or similar ML deployment pipelines Understanding of responsible AI practices - latency, cost, hallucination mitigation Nice to Have Experience in the time tracking, workforce management, or project management SaaS domain Frontend exposure - React or TypeScript - to collaborate closely with full-stack requirements Familiarity with multi-tenancy patterns and SaaS billing / subscription models Contributions to open-source projects or public technical writing Experience with observability tooling: Datadog, Open Telemetry, AWS X-Ray Engagement Details Duration: ~6 months Time zone: East Coast alignment required Work style: Highly collaborative, execution-focused, minimal bureaucracy