What a Junior } should know

5 core skills, 80 in total. Expectations per skill, and what changes at the next level.

This page lists what a Junior } 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: Machine Learning & AI, AI-Assisted Development.

5core skills

75additional skills

2skill areas

0%at Advanced or Expert

Assess myself as Junior Full role matrix

Core skills for a Junior

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

Machine Learning & AI · 3

LLM Evaluation Awareness

Knows basic LLM evaluation metrics: perplexity, BLEU, ROUGE. Runs standard benchmarks (MMLU, HellaSwag) under mentor guidance and interprets basic results.

LLM Fine-tuning Awareness

Knows LLM fine-tuning basics: full fine-tuning vs LoRA, instruction-tuning data format. Runs basic fine-tuning of a small model via Hugging Face Trainer under mentor guidance.

Vector Databases Awareness

Knows vector database basics: what is vector index, ANN search, distance metrics. Works with ChromaDB or Faiss for storing and searching embeddings in simple RAG applications.

AI-Assisted Development · 2

ChatGPT / Claude Awareness

Knows main ChatGPT and Claude API capabilities: request formats, temperature/top_p parameters. Uses API for simple text generation and classification tasks under mentor guidance.

Prompt Engineering for Code Awareness

Knows prompt engineering basics for internal use: system prompts, formatting instructions, output constraints. Creates basic prompts for LLM system components under mentor guidance.

Additional skills

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

AI Agent Frameworks AI Agents for Development Algorithms & Complexity API Documentation Async Programming AWS Code Quality & Refactoring Code Review Cursor IDE Data Structures Database Indexing Deep Learning Design Patterns Distributed Training Docker Elasticsearch / OpenSearch Embeddings & Vector DB Experiment Tracking Git Advanced GitHub Actions / GitLab CI GitHub Copilot GPU Programming GraphQL Design gRPC & Protocol Buffers Integration Testing Kubernetes Core Kubernetes Orchestration LLM Alignment LLM Applications LLM Deployment LLM Prompt Engineering LLM Safety LLM Scaling ML Deployment ML Experiment Tracking ML Model Evaluation ML Pipelines MLflow Model Context Protocol (MCP)Model Monitoring Model Serving Multithreading Natural Language Processing Network Fundamentals Neural Network Architectures OOP & SOLID Principles OpenTelemetry OWASP & Application Security Pandas / Polars PostgreSQL Prometheus & Grafana Python Programming Python Web Frameworks PyTorch RAG RAG Architecture Redis REST API Design RLHF Techniques S3 / Object Storage Secure Coding Practices Server-Sent Events & Streaming Structured Logging System Design Fundamentals Task Queues TensorFlow / PyTorch Terraform Tokenization Transfer Learning Transformer Architecture Transformers & NLP Type Safety & Type Systems Unit Testing Unit Testing vLLM Inference

What changes at Mid-level

80 skills get a higher expectation or become core when moving from Junior to Mid-level. The biggest jumps first.

ChatGPT / Claude: Awareness → Working
LLM Evaluation: Awareness → Working
LLM Fine-tuning: Awareness → Working
Prompt Engineering for Code: Awareness → Working
Vector Databases: Awareness → Working
AI Agent Frameworks: Awareness → Working
AI Agents for Development: Awareness → Working
Algorithms & Complexity: Awareness → Working
API Documentation: Awareness → Working
Async Programming: Awareness → Working

See the Mid-level page →

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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.

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} in the open competency matrix: 80 skills across 5 levels. The matrix is free for individuals and stays free.