Catalog · Nexora

Web Development intermediate

Web Security Essentials for Application Developers

The vulnerability classes that actually get exploited: injection, broken access control, XSS, CSRF and session fixation. Password storage, token design and cookie flags that matter, secret management, and a threat-modelling habit you can apply in a design review.

AR Ahmed Rahal 4.8

$75.00

11 hours

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Python

Python intermediate

Modern Python: Type Hints, Async and Packaging

The Python that ships in 2026: expressive type hints and generics, structural subtyping with protocols, asyncio concurrency patterns that avoid the common deadlocks, dependency management and reproducible builds, and a strict mypy configuration you can actually adopt on an existing codebase.

MA Marta Alves 4.8

$59.00

13 hours

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Data Engineering

Data Engineering intermediate

Vector Databases and Semantic Search at Scale

How approximate nearest-neighbour indexes actually work (HNSW, IVF, product quantisation) and what you trade for speed. Metadata filtering, hybrid dense plus sparse retrieval, reciprocal rank fusion, re-indexing strategies for embedding migrations, and keeping a vector store in sync with a relational system of record.

DO Daniel Okafor 4.8

$79.00

10 hours

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Data Engineering

Data Engineering intermediate

Data Engineering with dbt and Modern SQL

Treat analytics code like software. Layered model architecture, incremental materialisations, snapshots for slowly changing dimensions, data tests as contracts, and documentation that stays current because it is generated. Includes CI that blocks a merge when a data test fails.

NH Nadia Hussain 4.8

$79.00

14 hours

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Deep Learning

Deep Learning advanced

Fine-Tuning LLMs with LoRA and QLoRA

Adapt a large model on a single GPU. Parameter-efficient fine-tuning, 4-bit quantisation, dataset curation and formatting, catastrophic-forgetting mitigation, and evaluation that detects when your tune made the model worse at everything else. Includes the decision framework for fine-tune versus RAG versus prompt engineering.

AR Ahmed Rahal 4.8

$119.00

13 hours

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Machine Learning

Machine Learning beginner

Machine Learning Foundations with scikit-learn

The honest introduction: how to frame a problem, build a baseline, and know when your model is fooling you. Linear and tree-based models, proper cross-validation, leakage detection, class imbalance, and calibration. Every concept is implemented on real tabular data rather than a toy dataset.

SD Sofia Duarte 4.8

$49.00

18 hours

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Agentic AI

Agentic AI intermediate

Agentic RAG: Retrieval That Reasons

Naive RAG retrieves once and hopes. Agentic RAG grades what it retrieved, rewrites the query when results are thin, and decides when it has enough context. Covers relevance grading, query rewriting loops, hybrid dense plus keyword retrieval, reciprocal rank fusion and LLM-as-judge re-ranking, with honest evaluation of when each technique actually helps.

DO Daniel Okafor 4.8

$79.00

10 hours

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DevOps

DevOps intermediate

Incident Response and On-Call Engineering

The skill of staying calm and effective while production burns. Incident command roles, communication cadence, mitigation before diagnosis, alert hygiene that protects sleep, and blameless postmortems that produce fixes instead of blame.

AR Ahmed Rahal 4.7

$69.00

8 hours

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Data Engineering

Data Engineering beginner

Analytics at Speed with DuckDB

An entire analytics engine in a single process, and often faster than the cluster you were about to provision. Columnar execution, querying Parquet in place, larger-than-memory workloads, and where DuckDB stops being the right answer.

EV Elena Vasquez 4.7

$49.00

8 hours

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Deep Learning

Deep Learning advanced

Distributed Training with FSDP and DeepSpeed

When a model no longer fits on one GPU. Data, tensor and pipeline parallelism, fully sharded data parallel, activation checkpointing, and the communication patterns that decide whether adding GPUs actually makes training faster.

HT Hiroshi Tanaka 4.7

$129.00

15 hours

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Career Skills

Career Skills intermediate

Technical Interviews for Data and ML Roles

What ML and data interviews are really testing. Case-study framing, ML system design, SQL and coding under time pressure, communicating a trade-off out loud, and the project narrative that makes a portfolio memorable. Includes graded mock rubrics.

NH Nadia Hussain 4.7

$55.00

10 hours

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DevOps

DevOps intermediate

Observability: Logs, Metrics and Traces

Instrument a distributed system so incidents are short. Structured logging, metric cardinality discipline, OpenTelemetry tracing across service boundaries, SLOs and error budgets, and alerts that page a human only when a human is needed.

AR Ahmed Rahal 4.7

$79.00

12 hours

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