Senior ML Engineer - Fintech Engineering (m/f/n)

About the Position

Senior ML Engineer - Fintech Engineering (m/f/n)

InPost Pay is building its own fintech platform from the ground up. It’s a large-scale, international initiative where engineers will have the opportunity to shape the architecture, build core fintech components, and create solutions designed to operate at InPost’s scale.

We’re building a lean, highly effective engineering organization in Poland, with AI-native engineering at its core. We’re looking for strong engineers who are comfortable with agentic engineering, from experienced professionals building complex systems and engineering tooling to a new generation of engineers who have embraced AI-driven development from the start of their careers.

Responsibilities

• Model Lifecycle Track: Own agentic model iteration (experiment, evaluate, retrain, promote). Design the agent loop and graph and keep it reliable and cost-controlled.
• Model Validation Track: Own agentic validation and backtesting. Build agent loops that replicate and stress-test models and produce evidence packs for independent review.
• Build and ship credit-scoring and merchant-underwriting models end-to-end: feature engineering, training, validation, deployment, and post-production monitoring.
• Engineer point-in-time-correct features against the shared feature store for BNPL and MCA decisioning. Partner with Data Engineering on source contracts and freshness SLAs.
• Deploy and operate models with MLOps tooling: versioning, CI/CD for models, and champion/challenger or shadow deployment.
• Monitor production models for drift, stability, and performance degradation. Close the loop with retraining, recalibration, or rollback when thresholds are breached.
• Design models to be explainable and regulatory-defensible by construction. Document features, decisions, and validation evidence to support CCD2 creditworthiness assessment and audit review.

Requirements

• Experienced in applied ML at scale, covering the end-to-end lifecycle: feature engineering, training, validation, deployment, and monitoring.
• Skilled in model validation methodology: backtesting, population stability (PSI), discrimination (Gini/KS), calibration.
• Experienced in MLOps and production monitoring: model versioning, CI/CD, champion/challenger and shadow deployment, drift detection, and automated alerting.
• Skilled in point-in-time-correct feature engineering and feature-store consumption patterns.
• Familiar with explainability techniques (SHAP/LIME) and documentation for regulatory defensibility.
• Fluent in Python and SQL, with Spark/Databricks for large-scale model training and serving.
• Experienced with advanced agentic tooling and loop and graph engineering: context and tool design, guardrails, eval design with auditable outputs. You also have solid working knowledge of LLMs.
• Fluent in English (B2+).

Nice to Have

• Hands-on model validation or independent-review experience.
• CCD2 / consumer-credit regulatory requirements for creditworthiness assessment.
• Merchant cash advance (MCA) underwriting and merchant-risk data.
• Fraud-detection modeling (e.g., bust-out, first-party fraud).
• IFRS 9 provisioning / expected-credit-loss modeling.
• Real-time, low-latency model serving.

We Offer

• Greenfield, high stakes.
• Strategic impact on how AI-native ML is done across InPost.
• A modern stack and a lean, AI-native team. You have space to experiment with new technologies, including AI tooling, and bring them into production.
• A collaborative, fast-moving environment where autonomy and accountability go hand in hand.
• Hybrid, ideally one day a week in the Warsaw or Kraków office.
• We offer a B2B Contract.

About the Company

InPost Pay is building its own fintech platform from the ground up. It’s a large-scale, international initiative where engineers will have the opportunity to shape the architecture, build core fintech components, and create solutions designed to operate at InPost’s scale.

We’re building a lean, highly effective engineering organization in Poland, with AI-native engineering at its core. We’re looking for strong engineers who are comfortable with agentic engineering, from experienced professionals building complex systems and engineering tooling to a new generation of engineers who have embraced AI-driven development from the start of their careers.