A whiteboard made for teaching

Draw it. Explain it. Teach it.

One board for everything you teach. Write in real handwriting, grow a tree, wire a circuit that actually runs, paste code that colours itself, and present it all as slides.

Open LessonInk Watch it work
17
code languages
5
diagram types
0
sign-ups needed

Built for

  • Teachers and lecturers
  • Online tutors
  • Students taking notes
  • Coding bootcamps
  • Workshop leaders

Everything on
one board

No more jumping between a slide deck, a drawing app, a code editor and a circuit simulator. LessonInk puts the tools you reach for when you teach on a single board, so your lesson flows the way you explain it.

Real
handwriting

Hello class, today we forget learn gates

Remember: AND needs both inputs high!

Handwriting fonts with colour, highlight, underline and strike-through. Sticky notes shrink your writing to fit.

Circuits that run

Switches, lamps, resistors and logic gates. Press Run and watch current flow and bulbs glow.

A checker that explains

Finds wrong connections and missing names, then tells you how to fix each one.

Code that colours itself

Paste from VS Code and the language is detected, with syntax colours in 17 languages.

Diagram to code

Class diagrams become Java, Python, C# or TypeScript. ER diagrams become SQL.

Trees in
seconds

Family trees, topic breakdowns and mind maps. Press Tab to add a branch.

The complete list

Everything LessonInk does

Every tool in the app, in one place.

Write and draw

  • Pen, highlighter and eraser with pressure for pen tablets
  • Handwriting, neat, clean and code fonts
  • Colour, bold, italic, underline, strike-through and highlight
  • Sticky notes in six colours that fit your writing
  • Lines, arrows, rectangles and ellipses
  • Pictures: paste, drop or upload
  • Select, move, resize, snap and undo

Diagrams

  • Tree diagrams with automatic layout (top-down or left-right)
  • UML: classes, interfaces, actors, use cases and connectors
  • Flowcharts, ER diagrams and sequence diagrams
  • Connectors that stay glued to their shapes
  • Mermaid: write it, paste it or import from Markdown
  • A checker that finds mistakes and suggests fixes

Circuits

  • Logic gates, switches, batteries, lamps, LEDs and resistors
  • Wires with straight, rounded or curved corners
  • Run mode: click inputs and watch signals travel
  • Real voltage and current, with bright and dim lamps
  • Burn-out warnings and "how to fix" suggestions
  • Ready-made examples, from a lamp to a half adder

Code

  • Code blocks with syntax colours in 17 languages
  • Paste code and the language is detected for you
  • Line numbers, highlighted lines and light or dark themes
  • Drop source files straight onto the board
  • Generate Java, Python, C# and TypeScript from class diagrams
  • Generate SQL tables from ER diagrams

Present and share

  • Slides: mark frames, then present full screen with smooth zooms
  • Content snaps onto slides and moves with them
  • Live websites on the board
  • PDF export with pages, plus PNG and JPEG
  • Save and open .lessonink board files
  • Starter templates, and work saved in your browser as you go

In action

See how it teaches

A quick look at four things teachers do on a LessonInk board.

Circuits that behave like the real thing

Build with switches, batteries, resistors, LEDs and logic gates. Press Run and click the inputs: wires light up, bulbs glow brighter or dimmer, and an LED without a resistor burns out. Students see why, not just what.

  • Real voltage and current, worked out for you
  • Truth tables you can click through
  • Ready-made examples to start from
9 V 0.4 A: bright Circuit is OK

Diagrams that check your work

Draw a class diagram or a flowchart and press Check. LessonInk spots the mistakes a student would make, such as an arrow pointing the wrong way, a class with no name, or a loop in inheritance, and suggests the fix.

  • Plain-language suggestions, not error codes
  • Problems are marked right on the diagram
  • Classes, flowcharts, ER and sequence diagrams
AnimalDog - name: String+ speak(): void- breed: String+ fetch(): void Inheritance loop Animal and Dog each inherit from the other. Fix: keep only Dog → Animal (child to parent).

From a diagram to working code

Draw your classes once, then choose Java, Python, C# or TypeScript and get class skeletons with fields, methods and inheritance filled in. Draw an ER diagram and get SQL tables. Students see the link between the picture and the code.

  • Pick the language with one click
  • Add the generated code to the board as a code block
  • Download it as files
Student - name: String- age: int+ enrol(): void+ study(): void public class Student { private String name; private int age; public void enrol() { // TODO } public void study() { }

Use cases

What teachers make with LessonInk

One online whiteboard for the lessons that need more than text and a marker.

Programming and computer science

Draw UML class diagrams and flowcharts, show code with syntax colours, and generate Java, Python, C# or TypeScript from your diagram.

Open the whiteboard →

Electronics and digital logic

Build logic gates and circuits, click the inputs, and watch signals, bulbs and truth tables respond as they would on a real bench.

Try a circuit →

Family trees and mind maps

Grow a tree with one key, branch by branch. Ideal for family trees, topic breakdowns, revision notes and brainstorming.

Make a tree →

Databases

Sketch entity-relationship diagrams for students, then turn them into SQL tables to see how the picture becomes a schema.

Draw an ER diagram →

Slides and lesson notes

Mark slides on the board and present them full screen, then export the whole board as a paged PDF for students.

Build a lesson →

Online tutoring and workshops

Open it in a browser tab, share your screen, and write in handwriting fonts with sticky notes, pictures and live websites on one board.

Start a board →

How it
works

Three steps from a blank board to a lesson you can present, print or share.

Pick a topic tree, family tree, flowchart, class diagram, logic gates or circuit, or open a blank board. Reopen a saved .lessonink file any time.

Write in handwriting, add sticky notes, grow trees, connect diagrams, wire circuits and paste code. Press Check or Run to test what you built.

Mark slides and present full screen, export a paged PDF or an image, or save your board as a .lessonink file for next time.

Questions

Good to know

Do I need an account?

No. Open LessonInk and start drawing. There is nothing to sign up for.

Where is my work saved?

Your board saves in your browser as you work. To keep a copy or move it to another computer, choose File, then Save board. That gives you a .lessonink file you can open again with File, then Open board, or by dropping it onto the board.

What can I export?

A PDF with pages (whole board, a selection or what you see), PNG and JPEG images, and the .lessonink board file. Code generated from diagrams can be added to the board or downloaded.

Does it work on a tablet or with a pen?

Yes. It works with a mouse, touch screens and pen tablets, with pen pressure for strokes and pinch to zoom on touch.

Can I make UML class diagrams and flowcharts?

Yes. LessonInk has UML classes, interfaces, actors and use cases, plus flowcharts, entity-relationship diagrams and sequence diagrams. Connectors stay attached to their shapes, and a checker points out mistakes such as missing names or inheritance loops and suggests how to fix them.

Can I simulate logic gates and circuits?

Yes. Build with logic gates, switches, batteries, lamps, LEDs and resistors, then press Run. Signals travel along the wires, lamps glow brighter or dimmer, and parts that would burn out are flagged with a suggestion on how to fix the circuit.

Can I show code and turn diagrams into code?

Yes. Paste code onto the board and LessonInk detects the language and colours it, in 17 languages. A UML class diagram can be turned into Java, Python, C# or TypeScript class skeletons, and an ER diagram into SQL tables.

Is there a desktop app?

A desktop version is planned. For now LessonInk runs in your web browser.