AI and machine learning
RAG and Chatbots with LangChain
Build a LangChain chatbot that answers from PLC and drive manuals, cites the page, refuses what it cannot find, and is tested.
RAG and Chatbots with LangChain is a free, self-paced online course from EDWartens for engineers, developers and students applying AI to real work. It has 12 modules and takes about 15.1 hours, with written notes, a practice task per module, a practical project and a final assessment of 15 questions (pass mark 60%). Learning costs nothing and needs only a free account. The optional EDWartens Certificate of Completion, verifiable by code, is a one-off US$28.99 for you; it is not a vendor credential. Updated 1 November 2026.
- Free
- Intermediate
- 15.1 hours
- Self-paced
- Certificate optional
- Lab practice in your browser
No card, no trial. The course is free for good. Certificate US$28.99, optional.
- Who it is for
- Engineers, developers and students applying AI to real work
- Jobs
- Roles that use this skill: AI engineer, machine learning engineer, data analyst and automation developer. No course guarantees a job.
- Tools
- Google Colab or a laptop; LangChain, sentence-transformers, FAISS; a free OpenRouter key or Ollama. Hardware: none. A laptop with 8 GB RAM for the fully local build.
- Updated


After this course you can
By the end you will be able to:
- Load and chunk manuals with metadata
- Search with hybrid retrieval and a re-ranker
- Generate cited answers with a refusal rule
- Evaluate recall, correctness and refusal on a real test set
- Serve the chatbot with Streamlit or FastAPI
Who it is for, and what you need first
Who it is for
Engineers, developers and students applying AI to real work.
Level: Intermediate. Intermediate. Needs Python (the Python for AI course) and the Generative AI and LLM Foundations course, or equivalent.
What you need
Software: Google Colab or a laptop; LangChain, sentence-transformers, FAISS; a free OpenRouter key or Ollama..
Hardware: None. A laptop with 8 GB RAM for the fully local build.. What to download, and how.
How this course works
Watch the lessons
Short video lessons, one module at a time, at your own pace.
Read the notes
Open the Reading tab for the written notes and diagrams of the module.
Practise in the 3D labOptional
Try the module in the free 3D lab, in your browser.
Check yourself
Answer the questions to see what stuck before you move on.
Final assessment
Pass the final once you have been through the modules.
Certificate, if you want oneOptional
Optional, with a page anyone can use to verify it.
What you learn
12 modules in order, at your own pace. 15.1 hours of video lessons, with written notes and a practice task in each module.
- 1What RAG is, and what it fixes33m
- 2LangChain: models, prompts, chains46m
- 3Loading and chunking documents, with lab practice: 5m
- 4Embeddings, vector stores and hybrid search, with lab practice: 23m
- 5The basic RAG chain and chat memory, with lab practice: 6m
- 6Better queries: multi-query, fusion, decomposition, HyDE30m
- 7Routing and structured data, with lab practice: 13m
- 8Re-ranking and advanced indexing21m
Show the other 4 modules
- 9Evaluating a RAG system, with lab practice: 1h 3m
- 10Agentic RAG with LangGraph, with lab practice: 3h 36m
- 11Build, serve, keep private2h 22m
- 12Final assessment
Software you need
What to download, where from, what it costs and how to install it. Every link goes to the maker's own site, never a mirror.
Show what to download (4 tools)
Required
- 01Free, GPU time not guaranteed
Google Colab
Google, in the browser
- Runs on
- Any modern web browser
- Account
- A free Google account
Colab is free to use. In the free version GPUs and TPUs are heavily restricted and not guaranteed, sessions can run for at most 12 hours, and idle sessions are stopped. Paid plans give more reliable access.
Steps
- 1.Open colab.research.google.com and sign in with your Google account.
- 2.Click New notebook (or open the notebook your course links to).
- 3.For a GPU, choose Runtime, then Change runtime type, then pick a GPU if one is offered.
- 4.Type code in a cell and press Shift and Enter to run it.
- Save a copy to your Google Drive so your changes are kept.
- Files on the runtime are deleted when the session ends. Save outputs to Drive.
Open Google Colabcolab.research.google.com - 02Free models with rate limits
OpenRouter
OpenRouter, Inc., in the browser
- Runs on
- Any modern web browser (API works from any language)
- Account
- A free OpenRouter account
Models with IDs ending in :free cost nothing but are limited to 20 requests per minute and 50 requests per day. Buying at least 10 credits raises the daily free-model limit to 1,000 requests.
Steps
- 1.Open openrouter.ai and sign up.
- 2.Go to Keys in your account settings and create an API key. Copy it somewhere safe.
- 3.Pick a model whose ID ends in :free.
- 4.Call it with any OpenAI-compatible client using the base URL https://openrouter.ai/api/v1 and your key.
- Never paste your API key into shared code or public repositories.
- The list of free models changes over time. Check the model page before a class.
Open OpenRouteropenrouter.ai
Optional
Useful, not needed to finish the course.
- 03Free
LangChain
LangChain, Inc., a Python or npm package
- Runs on
- Any system with Python 3.10 or later
- Account
- None needed
Free, open source under the MIT licence. Model providers you call may charge for use.
Steps
- 1.Install Python 3.10 or later and create a virtual environment.
- 2.Run: pip install -U langchain
- 3.Install the package for your model provider, for example: pip install -U langchain-openai or pip install -U langchain-anthropic
- 4.Set your provider's API key as an environment variable and run the quickstart example from the docs.
- Keep API keys in environment variables or a .env file, never in shared code.
Official download pagedocs.langchain.com - 04Free
Ollama
Ollama Inc.
- Runs on
- macOS 14 Sonoma or later, Windows 10 or later, Linux
- Account
- None needed
Ollama is free and open source (MIT licence). Each model you download has its own licence; check it before commercial use.
Steps
- 1.Open ollama.com/download and pick your system.
- 2.On Windows run OllamaSetup.exe; on macOS open the DMG; on Linux run: curl -fsSL https://ollama.com/install.sh | sh
- 3.Open a terminal and run a small model, for example: ollama run <model name> (browse names on ollama.com).
- 4.Type a question at the prompt. Type /bye to exit.
- Models are several GB each. Check your free disk space first.
- More RAM, or a supported GPU, lets you run larger models faster.
- On Windows you can also install from PowerShell: irm https://ollama.com/install.ps1 | iex
Official download pageollama.com
Checked against each maker's own page on 27 September 2026. Trial lengths and editions change; the maker's page is the final word.
Practise in the 3D lab
Tune a document assistant by hand: set the chunking and retrieval so it cites the right section, make it refuse when the documents are silent, and keep an agent safe.
- Answers with sourcesAI Workbench, about 25 minOpen in the lab (opens in a new tab): Answers with sources
- A safe agentAI Workbench, about 30 minOpen in the lab (opens in a new tab): A safe agent
Optional. Skip it whenever you like: it never blocks your progress or your certificate.
Course project, about 9 hours
A manual-reading assistant over three vendor manuals, with citations and a measured score
Index a PLC manual, a drive manual and a transmitter datasheet with page metadata. Build a chain that cites (doc p.N) and answers NOT FOUND when the manuals are silent. Score it on a thirty-question test set, then show the answers on a Streamlit page with their sources. Free tools can run every step, though a long scored run may need Ollama or several days of a free hosted limit.
- 8documents in the pack
- 11steps to follow
- Laboptional: in the 3D lab
- 7things to hand in
- 9 hof work, at your pace
- PlanProject plan: manual-reading assistant for the service desk
- URSRequirements for the manual-reading assistant
- RegisterCorpus register: manuals indexed, editions and chunking
- SDSSoftware design: retrieval stack, prompts and interface
- RegisterTest-set register: thirty questions, extract
- Test reportEvaluation record: configurations A and B on the thirty questions
Do it in the lab: 4 steps.
The project is optional practice. The certificate needs only the modules and the final assessment.
After the course, your next step
Show what you can do, then keep going in the same field.
A certificate you can verify
Finish the modules and pass the final assessment (15 questions, pass mark 60%) and you can add a certificate with a public verification page. One-off, US$28.99 for you. It is not a vendor credential.
Want a free certificate? Do the matching Free internship: 4 weeks, nothing to buy, with a free certificate of completion.

Generative AI and Prompt Engineering
Eight short weeks of how language models work, prompting that gets better answers, and the risks to manage: notes, diagrams, a few videos and worked exercises. Finish weeks 1 to 4 and the final, then claim a free Internship Completion Certificate with your real dates and study hours, and a QR code anyone can scan to verify it. Training, not employment.
See the internshipPart of a learning path
Courses in a planned order, so each one builds on the last.
More free courses
Roles that use this skill
- AI engineer
- Machine learning engineer
- Data analyst
- Automation developer
These are the kinds of roles where the skill is used. We make no promise of a job or an interview.
Plain notes
- Free: the whole course, the notes, the practice tasks, the final assessment and support from practising engineers.
- Paid, and optional: the course certificate, and the Engineer-verified internship (the Free internship costs nothing).
- No job promise: the course teaches a skill. It does not place you in a job.
- Lessons by: LangChain, Krish Naik, codebasics, IBM Technology, KodeKloud, Microsoft Developer, freeCodeCamp.org, SingleStore, Tech With Tim. Independent creators; the lessons stream from their own channels. EDWartens wrote the study plan, notes, practice tasks and assessments.
LangChain · Krish Naik · codebasics · IBM Technology · KodeKloud · Microsoft Developer · freeCodeCamp.org · SingleStore · Tech With Tim. If you are one of these creators and want a lesson removed or credited differently, write to info@edwartens.com.
Practise what you learn in the free 3D lab
Technical work is judged on what you can do: wiring, commissioning, finding a fault. Doing a task yourself teaches more than watching it a second time, and a lab lets you try it safely before you meet real equipment. It does not replace working on real hardware.
- Practise safely, so a mistake costs nothing.
- The lab checks your work like a site test, so you know when it is right.
- Free, in your browser, with nothing to install.
Why learn with EDWartens
What you get with this course, and what comes after it.
- Free from the first lesson to the final assessment.
- Practice in a free 3D lab in your browser, with nothing to install.
- Video lessons with written notes and a project.
- An optional certificate that anyone can verify online.
- Free internships to keep practising afterwards.
Common questions
What do I need before this course?
Comfortable Python and the ideas from the Generative AI course: tokens, prompts and embeddings. If you have done those two courses you are ready.
Do I need a paid API?
No. Embeddings, the re-ranker and FAISS run locally, and hosted models are available on OpenRouter's free tier, which has daily request limits. A long scored run (about 55 calls for thirty questions with a judge) can pass those limits, so use the fully local build with Ollama or spread the run over several days. Ollama needs nothing online once the models are downloaded.
What are the projects in the RAG and Chatbots with LangChain course?
There are two projects. The first is a manual-reading assistant over three vendor manuals. It has citations, a re-ranker, a thirty-question evaluation and a Streamlit page. The second is an assistant over a year of maintenance work orders. It routes text questions to RAG and counting questions to templated SQL.
Why so much on evaluation?
Because a RAG demo is easy and a RAG tool is not. In the first project the service desk sets its own limits, such as recall above 0.85 and refusal at 1.0. Those are that scenario's numbers, not a standard. The course teaches you to set limits from the users and to prove you reach them.
Is the RAG and Chatbots with LangChain course really free?
Yes. Every module, practice task, project and assessment. You create an account so your progress is saved and the assessments can be marked. The certificate is the only paid item, and only if you want it.
What certificate does the RAG and Chatbots with LangChain course give?
An EDWartens Certificate of Completion, issued when you have finished the modules and passed the final assessment (the project is optional practice), with a verification code anyone can check. It is not a vendor credential and is never described as one.
Who made the video lessons in the RAG and Chatbots with LangChain course?
The creators named in the Credits block at the foot of this page, on their own YouTube channels. EDWartens did not make the videos and the creators are not affiliated with EDWartens. What EDWartens wrote is the study plan, the notes, the practice tasks, the projects and the assessments.
Do I have to use the lab?
No. The lab is optional practice. You can skip it whenever you like, and it never blocks your progress, the final assessment or your certificate.
Is the lab free?
Yes. Every lab level for this course opens in your browser, free, with nothing to install.
What topics does the RAG and Chatbots with LangChain course cover, module by module?
The RAG and Chatbots with LangChain course has 12 modules. It opens with "What RAG is, and what it fixes", goes through "LangChain: models, prompts, chains", "The basic RAG chain and chat memory", "Re-ranking and advanced indexing" and "Build, serve, keep private" and ends with "Final assessment". The full list with minutes is under "What you learn" on this page.
What can I do after the RAG and Chatbots with LangChain course?
After the RAG and Chatbots with LangChain course: Load, clean and chunk vendor manuals so parameter tables survive; Embed locally, search with hybrid BM25 + vector retrieval and re-rank with a cross-encoder; Build a RAG chain that cites (doc p.N), refuses with NOT FOUND and handles follow-ups. These are the practical outcomes the course is written around, and the final assessment of 15 questions checks them.
What software and hardware do I need for the RAG and Chatbots with LangChain course, and does it cost anything?
For the RAG and Chatbots with LangChain course, software: Google Colab or a laptop; LangChain, sentence-transformers, FAISS; a free OpenRouter key or Ollama. Hardware: none. A laptop with 8 GB RAM for the fully local build. The course itself is free.
Is the RAG and Chatbots with LangChain course suitable for me, and what level is it?
RAG and Chatbots with LangChain is rated intermediate. Intermediate. Needs Python (the Python for AI course) and the Generative AI and LLM Foundations course, or equivalent. It is written for engineers, developers and students applying AI to real work, and takes about 15.1 hours at your own pace.
Which jobs use the skills from the RAG and Chatbots with LangChain course?
Skills from the RAG and Chatbots with LangChain course (for example: load, clean and chunk vendor manuals so parameter tables survive) are used in roles such as AI engineer, machine learning engineer, data analyst and automation developer, and in machine learning engineer work. The course gives you practical evidence of the skill; it does not promise a job, and employers decide on experience and interview.
Start free today
RAG and Chatbots with LangChain, at your own pace. Add the certificate only if you want one.