Founding Data Engineer...

Founding Data Engineer London - Hybrid (3 days) - £70,000-£80,000 + meaningful equity Company Our client is a London-based, well-funded startup specialising in analytics and predictive ML models. They help mobile apps optimise ad spend by analysing behavioural data and delivering predictive signals for high-value conversions. As the first data engineer, you'll work directly with the founders to build core data infrastructure that powers real business impact. Responsibilities As the founding Data Engineer, you will own the design and implementation of data pipelines and infrastructure, including: Build production ETL pipelines processing millions of mobile analytics events from MMPs like AppsFlyer and AdjustEngineer features for ML models, including temporal patterns, user behaviour sequences, and campaign attributionEnsure data quality via validation, deduplication, schema checks, and defensive programmingOptimise pandas/Polars pipelines for performance at scaleHandle messy real-world data: duplicates, nulls, schema drift, and out-of-order eventsBuild and orchestrate pipelines using Prefect and monitor BigQuery operationsEstablish CI/CD practices and maintain clean, maintainable codeIntegrate APIs with MMPs and advertising platforms, and collaborate with data scientists to productionise ML modelsSet data quality standards and influence the technical strategy for the platform Requirements 4-6+ years of building production data pipelines with measurable business impactDeep expertise in Python, SQL, and pandas, with experience in memory optimisation and vectorisationExperience managing messy real-world data and maintaining high data qualit