Roles · ML Engineer · Lead

What a Lead } should know

24 core skills, 56 in total. Expectations per skill, and what changes at the next level.

This page lists what a Lead } is expected to know and do, skill by skill. Core skills are the ones a manager and peers assess in a review cycle; the rest count only in self-assessment. Main areas: Programming Fundamentals, Backend Development, API & Integration.

24core skills
32additional skills
8skill areas
100%at Advanced or Expert
Assess myself as Lead Full role matrix

Core skills for a Lead

Grouped by area. The label on the right is the expected depth: Awareness, Working, Advanced or Expert.

Programming Fundamentals · 4

Establishes algorithmic efficiency standards for ML systems in the team. Makes trade-off decisions between accuracy and speed at the architecture level. Evaluates ML pipeline scalability.

Shapes code quality culture in ML team. Introduces code review practices for ML. Standardizes approaches to ML component testing.

Data Structures Advanced

Defines data structure standards for ML team. Designs data abstractions for reuse across projects. Evaluates memory-efficiency of solutions.

Establishes OOP architectural standards for ML codebase. Conducts code review focusing on proper abstractions. Trains the team on ML framework design.

Backend Development · 1

Defines ML API standards for the team. Designs unified API gateway for ML services. Coordinates ML API integration with backend teams.

API & Integration · 1

REST API Design Advanced

Defines ML API design standards. Designs unified prediction API for all models. Coordinates ML API with frontend/backend teams.

Cloud & Infrastructure · 2

Docker Advanced

Defines Docker standards for ML organization. Designs container strategy for ML platform. Coordinates with DevOps on ML-specific container requirements.

Kubernetes Core Advanced

Defines Kubernetes strategy for ML platform. Designs multi-tenant ML infrastructure. Coordinates with Platform Engineering on ML requirements.

Testing & QA · 1

Unit Testing Advanced

Defines testing standards for ML organization. Introduces ML-specific testing practices (data tests, model tests). Trains the team on ML testing.

Data Engineering · 4

Apache Spark Expert

Defines Spark strategy for ML data processing. Evaluates Spark vs alternatives (Dask, Ray) for ML workloads. Designs distributed computing architecture for ML.

Data Quality Expert

Defines data quality strategy for ML organization. Introduces data quality culture in ML team. Coordinates with Data Engineering on data quality.

Defines data processing standards for ML team. Creates feature engineering framework. Trains the team on efficient data handling.

SQL-based ETL Expert

Defines ETL strategy for ML data. Coordinates with Data Engineering on ML data requirements. Designs data contracts for ML features.

Machine Learning & AI · 9

Defines scikit-learn usage standards in the organization. Evaluates sklearn vs deep learning for different tasks. Creates feature engineering framework based on sklearn.

Defines experiment tracking standards. Introduces culture of experimentation. Standardizes metrics and evaluation.

Defines feature store strategy for the organization. Evaluates Feast vs Tecton vs custom solution. Designs feature governance and discovery.

Defines gradient boosting usage strategy in ML organization. Evaluates gradient boosting vs deep learning for tabular data. Creates AutoML pipeline.

ML Pipelines Expert

Defines ML pipeline strategy. Standardizes pipeline components. Designs pipeline templating for faster development.

MLflow Expert

Defines experiment tracking strategy for the organization. Evaluates MLflow vs W&B vs ClearML. Designs model governance workflow. Standardizes ML lifecycle.

Defines model monitoring strategy. Standardizes monitoring practices. Designs model observability platform.

Model Serving Expert

Defines model serving strategy for the platform. Designs unified serving layer. Optimizes serving costs. Coordinates with DevOps on infrastructure.

PyTorch Expert

Defines deep learning strategy for the organization. Designs training infrastructure. Standardizes training patterns and evaluation. Coordinates GPU resources.

Version Control & Collaboration · 2

Code Review Advanced

Defines code review practices for ML team. Conducts architecture review for ML projects. Trains the team on effective review.

Git Advanced Advanced

Defines Git practices for ML organization. Designs repository strategy for ML. Standardizes branching model and review process.

Additional skills

Not assessed by the team, but part of the self-assessment and the development plan.

API DocumentationData Modeling & Schema DesignE2E TestingGraphQL DesignJWT / OAuth2 / OIDCMemory ManagementNetwork FundamentalsOpenTelemetryOWASP & Application SecuritySecure Coding PracticesSLI / SLO / SLASystem Design FundamentalsTerraformType Safety & Type SystemsWebSocket API DesignApache KafkaAsync ProgrammingAWSChatGPT / ClaudeCursor IDEDatabase IndexingDesign PatternsGitHub Actions / GitLab CIGitHub CopilotgRPC & Protocol BuffersIntegration TestingMultithreadingPostgreSQLPrompt Engineering for CodeQuery OptimizationRedisTask Queues

What changes at Principal

18 skills get a higher expectation or become core when moving from Lead to Principal. The biggest jumps first.

See the Principal page →
Run this with your whole team
Self-assessment plus manager and peer reviews against the same matrix, gap analysis and next-level readiness for every engineer. Team Pro is free for 14 days; individual tools stay free forever.
Start a team trial (14 days free) Send to my manager

} in the open competency matrix: 56 skills across 5 levels. The matrix is free for individuals and stays free.