Works with your subscription
One connector in your assistant’s settings — no separate app and no separate payment.
Courses you take inside your own AI assistant
You connect L-System to Claude, ChatGPT or another assistant — and it walks you through the course the way that suits you: at your pace, with your examples, in your language. We remember where you stopped. The exam you take yourself, here, without the assistant.
Signing up is free
Taught your way
Shorter or deeper, with tasks from your own work, with diagrams described in words — you ask, the assistant rebuilds.
Language is not a barrier
Your assistant explains things in your language even when the course is written in another. The course text and the exam questions stay in the author’s language — it is shown on every course.
Your own course in an evening
Ask your assistant to build a course out of your materials — for students, for colleagues, or just for yourself.
Starting costs nothing
Most of the catalog is open for free, exam and certificate included.
The course path
- 1Pick a course
Enrol for free straight from the catalogue.
- 2Paste the connector
Into your assistant’s settings, once. Takes a minute.
- 3Learn in the chat
The site is for later — for the exam and the certificate.
- 4Exam and certificate
The exam runs on the server, without the assistant. Verified by link.
The exam goes past the assistant
Questions are never handed to it: your helper may teach, but only you may answer. That is why the certificate means something, and why anyone can check its signature.
Start today
Whole catalog — 8 coursesSQL for QA Engineers: T-SQL in Everyday Testing
A working course in T-SQL for QA engineers in professional services firms who already know the basics — SELECT, WHERE, a simple JOIN — and now need SQL as a daily testing instrument rather than as a topic. Everything is set in ENGAGE, the fictional engagement and billing platform of Aldervane Advisory LLP: clients, engagements, staff, timesheets, approvals, invoices, an audit log and a migration staging table. One schema, carried through every unit, so the examples are the ones you actually meet — a report total that disagrees with the raw rows, a record the UI claims it saved, a migration that quietly dropped a hundred time entries, a duplicate that only appears under a business key. Each construct is introduced the same way: the problem that makes you reach for it, the construct itself, and the price it charges. LEFT JOIN buys you the missing rows and charges you row multiplication. NOLOCK buys you speed on a shared environment and charges you dirty reads. A green test that never asked the right question costs more than a red one. Nineteen core units cover reading an unfamiliar schema, staying safe on a shared test environment, NULL and three-valued logic, data types and collation, dates and time zones, joins and orphan records, set operations as reconciliation, aggregation, subqueries, CTEs, window functions, test data setup and idempotent teardown, verifying what the application wrote, reading someone else's views and triggers, and turning a SQL check into a deterministic assertion. Five optional units add a local sandbox script, execution plans, client data and AI assistants, an end-to-end migration reconciliation checklist, and normalisation as an explanation of why the schema looks the way it does. Units are open in any order: come for the whole course, or come for the one thing that is biting you today. Scope note: the course teaches you to write queries and to read them. Practice covers both; the certification exam checks reading, recognition and knowledge of constructs, since a written query cannot be machine-verified here.
English: Phrasal Verbs
A basic set of English phrasal verbs: how they differ from a verb with a preposition, verbs about people and relationships, verbs about actions and plans.
Playwright Test Automation for QA Engineers
A full working course on Playwright with TypeScript for QA engineers in large professional-services firms (Big 4 and similar). It covers the same ground as a comprehensive "zero to hero" Playwright curriculum: TypeScript essentials for test code, installation and project layout, running and debugging (CLI, UI mode, Inspector, codegen, Trace Viewer), locators and the strictness rule, web-first assertions, auto-waiting and the timeout hierarchy, every common UI component (inputs, checkboxes, radios, dropdowns, tooltips, dialogs, tables, date pickers, sliders, iframes), the Page Object Model and a scalable page architecture, custom fixtures, configuration and projects, environment variables and mobile emulation, authentication reuse through storageState, artifacts and reporters, visual regression testing, API requests, network interception and mocking, parallelism, retries, tags and flakiness control, Docker and CI on GitHub Actions. Every topic is taught the same way: the problem that exists without the feature, the feature that solves it, and the price you pay for using it. The course is written for people who will maintain a suite on a client engagement for years, not for people writing a demo test once — so review criteria, evidence for audit, secret handling and cost of maintenance are part of the material, not an appendix. By the end you should be able to build and maintain a Playwright suite unaided, and to pass an external certification-style exam on the same syllabus.