Location: UK or Portugal

Department: Engineering

Employment Type: Permanent

About YLD:

Our goal is to help our clients keep moving forward. We work with them to build the skills and capabilities they need to stay ahead of the competition, and we know our success only happens when they succeed. We’re a team of curious, talented people, and we’re committed to making YLD a place where great people want to work, grow, and stay. We’re a remote-first consultancy specialising in software engineering, product design, and data. Our teams are based across London, Lisbon, and Porto, and we create digital solutions that continue to deliver value long after our work is done.

About the role:

As a Senior Data Engineer, you’ll be part of a client team building innovative products. We expect you to be curious, passionate, driven, and enthusiastic. You’ll be proficient at problem-solving, and crafting scalable, resilient, and fault-tolerant architectures. You’ll be an effective communicator and a team player. You and your team will move in a fast-paced engineering environment, achieving outstanding results and delivering exciting projects.

About you:

A YLD Senior Data Engineer is a highly skilled engineer who spans across data engineering and analytics engineering, and knows where the boundaries sit. You've built pipelines and transformation layers. You've inherited messy data projects and made them good. You have opinions about how data teams should work and the humility to adapt them to context.

You have a real passion for the craft and are an active learner who gets excited by the variety that consultancy brings: different clients, different stacks, different problems.

Your day-to-day responsibilities will look like this:

• Delivering data work on client engagements: pipelines, transformation layers, models, and the infrastructure around them
• Adapting to different client contexts, legacy warehouse migrations, greenfield lakehouses, struggling transformation layers that need rescuing
• Defining and evolving our internal standards for data work: testing, documentation, project structure, code review
• Mentoring and growing data engineers across the company
• Showing up for client team moments (internal speakers, learning sessions, social events) to build strong working relationships.
• Contributing to proposals and helping shape engagements during the sales process
• Representing YLD externally through writing, speaking, and contributing to the wider data community.

You’ll have the following skills and experience:

• SQL as engineering: You write SQL that's reviewable, testable, and performs at scale. You understand query planning, engine quirks, and how materialisation choices affect cost and performance
• Python for data: You write typed, testable Python for pipelines and tooling. You've built and maintained production data systems, not just notebooks
• Data modelling: You've made deliberate choices between dimensional, Data Vault, normalised, and denormalised designs. You can explain those trade-offs in terms of flexibility, query performance, and maintainability
• Transformation architecture: You design transformations that are idempotent, incremental, and dependency-aware. You think in DAGs, not scripts
• Pipeline design: You understand batch, streaming, and micro-batch trade-offs. You consider latency, complexity, cost, and reprocessability. And choose the right approach for the problem
• Data testing: You write tests as code, schema contracts, assertions, and transformation logic. You know what to catch at build time vs. defer to observability
• Data observability: You treat data reliability like site reliability. Measurable indicators, alerting, incident response, and root cause analysis
• CI/CD for data: You version, test, and deploy pipelines like software. Environment promotion, rollback strategies, and infrastructure as code for reproducible environments
• Data governance: You've implemented lineage, cataloguing, sensitive data classification, or access control. Not just built pipelines, but made them auditable and secure
• Cost-conscious: You've optimised warehouse spend, storage strategies, or job efficiency. You treat compute as a resource to manage, not ignore
• Platform fluency: You've worked across the modern stack. Orchestration (Airflow, Dagster), warehouses (Snowflake, BigQuery, Databricks), ingestion (Fivetran, Airbyte, custom), and transformation (dbt, Spark)
• Cross-functional fluency: You translate engineering constraints into business terms and negotiate realistic commitments

You’ll be:

• Self-motivated and proactive
• Comfortable with ambiguity, experimentation, and iteration
• Collaborative by default. You work well in teams and across teams
• Analytical and detail-oriented in your approach to problems
• Comfortable context-switching across clients, stacks, and problem types
• Willing to shape engagements, not just deliver them: contributing to proposals, scoping, and client relationships
• Active in the wider data community: writing, speaking, or open-source contribution
• Genuinely committed to diversity, equity, and inclusion

Benefits you'll get:

• Company Private Health care
• Enhanced fully paid maternity and paternity leave for up to 6 months
• Company’s Pension Scheme (UK Only)
• 25 days annual holiday (excluding Public Holidays)
• £2000/€2000 annual allowance for Training/Conferences
• £300/€300 annual allowance for additional hardware
• Wellbeing & Performance Support via Oli including Therapy and Coaching
• Discretionary Bonus (depending on Company performance and results)
• Company laptop
• Generous referral schemes

Our typical Recruitment Process looks like this:

• 1st Interview with someone from the Talent team (30-45 Minutes)
• Technical Interview with our Senior Developers (90 Minutes)
• Call with the Head of Engineering (60 Minutes)

Get a glimpse of what it's like working at YLD! 🤳

Check out our LinkedIn page

We live and breathe our values, and know you will too:

• Growing every day
• Including everyone
• Relationships built on honesty and ethics
• Inspiring solutions
• Winning together

We’re an equal-opportunity employer and value diversity in all its forms. We do not discriminate based on race, religion, colour, national origin, gender, sexual orientation, pregnancy or maternity, age, marital status, or disability. We also offer a remote-first working environment, with flexible working and work–life balance as standard for all employees.

About the Role 

We are looking for a Senior .NET Developer who combines deep technical expertise with a passion for code quality, mentorship, and collaborative delivery. In this role you will lead efforts to modernize and evolve our platform, drive engineering best practices, and work alongside product, design, and data teams to ship reliable software at scale.

You bring a proven track record in .NET development, a sharp understanding of modern deployment pipelines, and the architectural awareness to build systems that scale across tenancy models and data workloads.  

Core Responsibilities 

Technical Leadership & Code Modernization 

• Lead architectural decisions for migrating a legacy single tenant .NET 8 application into an existing multitenant framework. 
• Champion clean code principles and drive technical roadmaps that reduce technical debt while maintaining delivery velocity. 
• Evaluate and introduce tooling, libraries, and frameworks that improve developer experience and system reliability. 
• Mentor junior and mid-level engineers through pairing, design reviews, and structured knowledge-sharing sessions. 

Code Review & Quality Assurance 

• Conduct constructive code reviews that uphold team standards and serve as teaching opportunities. 
• Define and enforce coding standards, naming conventions, and architectural guidelines across the team. 
• Identify systemic quality issues through review patterns and proactively propose process improvements. 
• Act as a trusted technical reviewer for high-risk or cross-cutting changes before they reach production. 

Cross-Functional Collaboration 

• Partner closely with stakeholders to translate business requirements into accurate technical estimates and clear implementation plans. 
• Collaborate with data engineers on warehouse integrations and backend data pipelines, ensuring scalable and maintainable interfaces. 
• Work with DevOps and platform teams to define deployment patterns and promote infrastructure-as-code practices. 
• Facilitate cross-team alignment through clear written communication, architectural decision records (ADRs), and documentation. 

Quality Engineering & Testing with TDD 

• Apply test-driven development (TDD) as a core engineering discipline, writing unit, integration, and contract tests before implementation. 
• Design and maintain test suites that give the team confidence to refactor and deploy frequently. 
• Champion a shift-left testing culture by embedding quality practices into every stage of development, not just QA cycles. 
• Ensure test coverage benchmarks are defined, tracked, and continuously improved. 

Communication & Process Leadership 

• Lead sprint ceremonies including planning, retrospectives, and backlog grooming with clarity and accountability. 
• Produce high-quality technical documentation including runbooks, API contracts, and onboarding guides. 
• Surface blockers and dependencies early, communicating status and risk proactively to stakeholders. 
• Contribute to a culture of psychological safety where candid, constructive feedback is the norm. 

Required Qualifications 

• 5+ years of professional software development experience with a focus on .NET. 
• .NET proficiency, including ASP.NET Core, Entity Framework Core, and the modern .NET runtime ecosystem. 
• Demonstrated experience modernizing legacy web applications — refactoring, re-architecting, or re-platforming from older monolithic web applications to modern platform fabrics. 
• Solid understanding of CI/CD pipelines, including pipeline design, automated test gating, artifact management, and deployment strategies (blue/green, canary, rolling). 
• Clear understanding of single-tenancy vs. multi-tenancy architecture patterns and the trade-offs in security, isolation, scalability, and cost. 
• Experience with test-driven development and a strong testing philosophy covering unit, integration, and end-to-end coverage. 
• Strong written and verbal communication skills; able to write clear technical documentation and lead design discussions. 

Preferred Qualifications 

• Claude code, Copilot, or the leverage of any AI platform to increase production output is a strong plus. 
• Experience with large-scale data warehousing solutions; Google BigQuery experience is a strong plus. 
• Frontend experience with Vue.js 3 — component architecture, Composition API, and state management patterns. 
• Familiarity with observability tooling such as OpenTelemetry, Prometheus, Datadog, or similar. 
• Experience working in a platform or multi-product engineering environment. 

Benefits:

• Five9 Shares
• Bonus Scheme
• 10% Flexi Benefit
• Meal Allowance
• Medical Insurance
• Life Insurance 
• 25 day Annual Leave + Public Holidays