Senior Data Scientist

Who you are

• Statistical foundations. You have a background in probability and statistics from a quantitative field. You reason about uncertainty and calibration as first-order concerns
• Production ML. You have built and shipped supervised ML models end to end – exploration, training, deployment, monitoring
• Research mindset. You proactively explore new ways to add value. R&D time is when you expect to find the next step change
• Judgement. You critically evaluate model output – yours, a colleague's, or an LLM's – and can explain why a choice is right. You defend your reasoning under challenge, and challenge others' when the evidence points elsewhere. You've influenced technical direction beyond your own projects
• Project leadership. You've owned modelling projects end to end, from spotting the opportunity through framing, method choice, shipping, and landing the commercial impact. You move fast, iterate, and update on new evidence rather than chase perfection
• AI fluency. You use AI as a primary tool. You prototype with it, automate with it, and take on R&D that would not otherwise be viable. You use judgement on where it helps and where it doesn't
• Communication. You write and speak clearly, directly, and concisely. You adapt technical detail to your audience
• Domain experience. You have worked in credit risk, lending, or customer lifetime value modelling
• Non-linear methods. You have shipped gradient boosting or neural networks on tabular data in production
• Bayesian methods. You have used hierarchical models, MCMC, or Bayesian updating in real work
• Time series modelling. You have modelled temporal data where autocorrelation, drift, or seasonality mattered
• Python. The stack the team uses

What the job involves

• We’re looking for a Senior Data Scientist to join our Credit Risk Modelling team
• You'll shape how iwoca models credit risk – setting the technical direction on multi-quarter projects, and lifting the bar for the team as you go
• The Credit Risk Modelling team owns credit risk and Customer Lifetime Value (CLtV) modelling for iwoca's UK and German lending. That covers the probabilistic machine learning models behind every credit decision, plus the CLtV models that shape pricing and portfolio strategy
• The team is around twelve data scientists. Some work on auto-space models that decide within five minutes from data candidates authorise us to pull. Others work on manual-space models that pick up when a credit analyst adds digital footprint and income data, which lands a decision within 24 hours
• You'll own credit and CLtV modelling projects end to end, from spotting where the modelling stack is holding the business back through to landing the change
• The work spans keeping production models healthy, incremental development, and research that reshapes how the models work
• AI has lowered the cost of prototyping enough that ideas which used to sit below the priority line are now viable, so the R&D share of the role is growing
• Live examples of the work:
• Unifying auto and manual models. The two families were built without forced technical alignment. Finding a principled way to unify them on a common cost function is open work
• IFRS accounting model. A multi-stage credit model where information propagates back from later-stage recovery predictions to sharpen upfront loss estimates
• Generalising credit and CLtV. Whether a more general framing could replace both separate models is an open research question

Benefits

• Work where you work best: Twice a year we rent houses in places like Sicily and the French Alps where each team can work together for a week poolside. We champion flexible working in all our teams
• Invest in iwoca: We want people to be invested in iwoca's success so after six months you'll be awarded share options
• Keep yourself healthy: We offer comprehensive health insurance and cash plans. You'll also get gym discounts and we host yoga classes in the office every week
• Start (and end) your day right: Each floor of iwoca HQ has a fully stocked fridge for breakfast and every Friday we unwind with beers and wine
• Life-work balance: We know your life outside of work comes first. We offer enhanced maternity and paternity leave for new parents plus a nursery benefit. We also have unlimited unpaid leave
• Learning and development: Whether you want to learn to code, experiment with motion design, or beat cognitive biases, you'll have time and budget to invest in your professional development