Machine Learning Engineer Express Scripts Canada

Job Title: Machine Learning Engineer

Location: Mississauga
Employment Type: Full-time

Reason for Vacancy: Replacement

Work Arrangement: Hybrid
Department Name: Application Delivery Department

Pay Typed: Salaried

Pay Range: $115000 - $125000

Please note that this is a general posting range and offer range will be varied based on relevant experience qualifications skills required and location for this role.

About Us

Express Scripts Canada (ESC) is the leader in health benefits management. Serving over 12 million members we help insurance carriers third party administrators and the public sector optimize the value of health benefits by linking the talent and professional expertise of our people with leading edge

information management systems and technology. Express Scripts Canada is a wholly owned subsidiary of Express Scripts one of the largest pharmacy benefit management (PBM) companies in North America part of The Cigna Group (NYSE: CI) a global health company. Together we deliver innovative

cost-effective solutions that improve access affordability and health outcomes for Canadians.

Job Summary

Express Scripts Canada is looking for a Machine Learning Engineer to join our Team. The successful candidate will design build and operate data pipelines and ML services that detect unusual patterns in healthcare claims and pharmacies.

The role blends hands-on data engineering (Oracle ETL) model development (unsupervised learning) and API serving (Python/FastAPI) with close collaboration across business teams. Youll ensure the best possible performance quality and responsiveness of the applications and pipelines and help maintain code quality organization and automation.

Key Responsibilities:

• Design & implement ML data pipelines to ingest engineer and persist features from Oracle (SQLAlchemy/oracledb) including robust logging argument-driven CLI tools and environment-based configuration (.env).

• Build and validate unsupervised ML models (e.g. MiniBatchKMeans/KMeans DBSCAN) with dimensionality reduction (TruncatedSVD/PCA) leveraging chunked processing and sparse matrices for large datasets; evaluate using silhouette/Calinski-Harabasz/Davies-Bouldin and stability checks.

• Serve models as REST APIs (ie. FastAPI/Pydantic) with health endpoints CORS structured response models and joblib artifact loading; instrument application logs and operational run scripts.

• Orchestrate end-to-end validation (DB feature engineering API scoring curated outputs) writing curated results back to Oracle tables and creating/maintaining schemas and DDL where required.

• Collaborate with business teams to interpret clusters/risk buckets explain top contributing features and incorporate feedback loops into subsequent runs and outputs.

• Support deployment workflows in sandboxed/on-prem environments; participate in CI/CD (e.g. Jenkins/OpenShift pipelines) as part of model operationalization.

• Ensure performance quality and responsiveness of data pipelines and APIs; help maintain code quality organization and automation; perform code reviews and follow Agile ceremonies.

• Understand how AI is interpreting the data set and use that understanding to build prompt that lead to expected outcomes

• Develop and maintain AI pipelines including data preprocessing feature extractions model training and evaluation

What Were Looking For

• 5 years application development experience;35 years of professional experience in data science / machine learning engineering with Python including productionizing data pipelines or ML services

• Bachelors degree in Computer Science Data Science Engineering Mathematics or a related field (or equivalent practical experience).

• Core programming (Python): Strong with NumPy pandas scikit-learn SciPy (sparse) joblib CLI (argparse) and data visualization (matplotlib/seaborn).

• Modeling (Unsupervised): Practical experience with MiniBatchKMeans/KMeans DBSCAN TruncatedSVD/PCA cluster evaluation (silhouette CH DB) and stability/bootstrapping.

• Data engineering and Oracle: Writing performant SQL; using SQLAlchemy and oracledb for reads/writes; creating tables/DDL; batch inserts; column/type normalization.

• ETL pipelines: Feature engineering over large volumes with chunked processing environment-aware configs (.env) robust logging and CSV/DB outputs.

• APIs and integration: Batch prediction flows via REST (e.g. httpx client) and schema-compatible exports

• Version control and CI/CD: Proficient with Git; familiarity with Jenkins/OpenShift pipelines and on-prem deployment constraints.

• Experience in Healthcare domain with exposure to Fraud Waste and Abuse detection in pharmacy/claims risk scoring thresholds and audit support artifacts considered a strong asset.

• Experience with on-prem masked datasets and familiarity with Docker/OpenShift deployment patterns for ML APIs.

Why Join Us

• Competitive compensation benefits and pension plan

• Career development and advancement opportunities

• A culture that celebrates innovation and collaboration

• Flexible work options and wellness programs

Pre-Employment Requirements

All offers of employment are conditional upon the successful completion of reference checks and background verification in accordance with company policy. Within ESC for certain positions obtaining and maintaining a federal government security clearance is a bona fide occupational requirement. Candidates applying for such roles must meet all eligibility criteria for the applicable clearance level and consent to the security screening process as mandated by federal regulations. Failure to obtain or maintain the required clearance will result in withdrawal of the offer or termination of

employment.

Our hiring process includes AI-powered tools to conduct video interviews take notes and score candidates; however all scores will be reviewed by hiring managers and our Talent team before making a decision.

NOTE: Internal candidates should apply before April 17 2026.