Tools you learn by using
Learning resources and practice environments we built and published. Nothing to download, nothing to install.
Three of them
New · EU Battery Regulation
Battery passport duty checker
If you place batteries on the EU market, you may need a battery passport from 18 February 2027. Answer a few questions to see whether, from when and what goes in it, each with its article. Your answers are never sent to our server.
New
Ontology checker
Check an OWL ontology for modeling pitfalls, metadata, logical contradictions, data constraints and term-registry matches. Files stay in your browser.
New
OntoOffice
Open HWP, HWPX, PDF, DOCX, XLSX, PPTX, CSV, TXT, MD, HTML, and PlantUML files in your browser and download the text and tables as Markdown, CSV, or JSON. Files are never sent to our server.
Smart home standard
Matter Learning Hub
A guide to the Matter smart home standard for beginners, planners and developers. Written in Korean.
- Protocol stack and mesh network visualization
- Commissioning walkthrough
- Certification process and certified products
- Search and bookmarks across terms, products and FAQs
Embedded practice
CircuitCraft
A virtual lab for wiring circuits and running code in the browser. AI suggests connections and catches shorts as you work.
- Arduino, ESP32, nRF52840, Raspberry Pi
- Six sensor modules with live telemetry
- Automatic bill of materials
- JavaScript AVR emulation core
Diagram editor
PlantUML Studio
Write PlantUML and watch the diagram follow as you type.
- Sequence, class, Gantt, mind map and eight more
- Start from a template
- Export to PNG, SVG, PDF
We build and maintain all three ourselves. Tell us what breaks, or what you wish it did.
Build with us
Need a tool we haven't built
We can build one that fits your site, or fold it into a training programme.