Building Systems with the ChatGPT API vs Generative AI with Large Language Models

The course is tightly structured across 11 short lessons: how LLMs and tokenization work, the chat format, input classification, the Moderation API, chain-of-thought reasoning, prompt chaining, output checking and system-level evaluation, all tied together by a running customer-service example. Reviewers repeatedly praise the clarity and the theory-to-practice balance. The honest mark-down is depth and age: it was built on GPT-3.5 Turbo in 2023, so it predates tool calling, structured JSON outputs and reasoning models, and it does not go deep on real-world deployment beyond the safety checks.

Isa Fulford (Member of Technical Staff at OpenAI) demonstrates while Andrew Ng frames the concepts, and reviewers consistently call the pairing knowledgeable and effective communicators. The teacher-demonstrator dynamic mirrors how a beginner actually thinks through each step, and the pacing of 5-20 minute lessons keeps momentum. This is the most authoritative free source for building multi-step LLM systems, and it shows.

Free on the DeepLearning.AI platform with runnable in-browser notebooks, and free to audit the Coursera version. For roughly 90 minutes of content that teaches a reusable architecture for chaining LLM calls, the value is hard to beat. The only caveats are that the platform's graded assignment and certificate sit behind a Pro upgrade, and that the aging notebook code can eat time if you insist on running it locally rather than in-browser.

The standout feature for most reviewers is the hands-on coding: you build prompt chains that consume prior completions, glue Python around model calls, and assemble a full customer-service chatbot that classifies queries, moderates input, reasons step by step and evaluates its own output. The caveat is that there is no graded, kept portfolio artefact on the free tier, and the supplied notebooks now require fixes (deprecated API syntax, missing Utils.py and products.json) to run outside the course sandbox.

The patterns taught — chaining, moderation, evaluation, routing — are exactly the building blocks of production LLM features, and developers report the course gave them a structured mental model they could apply immediately. But it is a one-hour primer with no certificate on the free tier and no capstone, so on its own it is a strong foundation rather than a credential. Its career value is as the second step in a sequence, not a destination.

Across three weeks (roughly 16 hours), the course covers the full generative AI project lifecycle: the Transformer architecture from the "Attention Is All You Need" paper, prompt engineering, in-context learning, Chinchilla scaling laws, instruction fine-tuning, parameter-efficient fine-tuning (LoRA), and reinforcement learning from human feedback (RLHF). Reviewers repeatedly praise how it grounds each technique in the relevant research paper before showing the "how," which builds genuine understanding of the "why." The most consistent content criticism is that week three squeezes too many topics (RLHF, model optimisation, RAG, ReAct) in at shallow depth and feels disjointed after the RLHF section.

The course is fronted by Andrew Ng with AWS instructors Antje Barth, Mike Chambers, Shelbee Eigenbrode and Chris Fregly delivering the technical content. Reviewers describe the delivery as technically clear, well-diagrammed and well-paced, with one calling Andrew Ng "like a rock star in Artificial Intelligence teaching." The multi-instructor AWS panel draws consistently positive marks for explaining production concepts from real experience, though it is a panel format rather than a single narrative voice.

At roughly USD 49 with six months of access — and the AWS SageMaker lab compute included in that price — multiple reviewers explicitly call it "not overpriced" for the breadth of current, applied content. The main value caveats are that the labs do not require writing original code (so you can finish for the certificate without coding), and that the included lab budget is finite — at least one learner exhausted it after a technical glitch on the very first lab and could not continue.

The three SageMaker labs (dialogue summarisation prompt engineering, PEFT fine-tuning with LoRA, and RLHF detoxification) give learners an end-to-end view of real LLM pipelines using PyTorch and the Hugging Face transformers library. The near-universal complaint is that the labs are "run all the cells" walkthroughs with no original coding, no graded homework, and no self-built project — you can submit by clicking through. Reviewers value them as illustrations but warn they do not verify skill or prepare you to build a similar application from scratch.

The curriculum maps closely to how LLM applications are actually scoped, adapted and deployed in industry — model selection, cost-aware optimisation (quantisation, pruning, distillation), fine-tuning strategy, RLHF alignment and RAG-style augmentation. The modern toolchain (SageMaker, Hugging Face, PyTorch) is exactly what practitioners use. The gap is between conceptual fluency and hands-on ability: because the labs require no original code, several reviewers recommend pairing the course with a build-it-yourself resource such as the Hugging Face NLP course to close the implementation gap.