See everything you know.Keep it lit.
A free place to learn, where each topic comes only after the ones it needs. Short sessions light up what a learner knows, and bring a topic back before it fades.
Pick where they are and start right in your browser. No sign-up, nothing to install.
- 1,739 topics
- 3,581 prerequisites
- 7 curricula
- free, no card
Real topics in real order: early Mathematics. Tap any star to open it.
How it works
Sessions are short. The same three things happen, over and over.
Find where they are
A few questions, not a test. One right answer credits everything under it, so placing a learner takes minutes.
Teach the next thing
Refreshers first, then a topic they can actually start. Never one whose prerequisites are missing.
Come back before it fades
Every topic has a half-life. It comes back just before recall slips, which is cheaper than relearning it.
What a lesson looks like
Every topic is drawn, not just described. Tap one to read the whole thing.
One sky, two ways to read it
The learner sees their sky
Lit means learned, glowing means almost. Nothing is ever marked wrong in red.
You see where things stand
Levels per subject, what is fading, and where five minutes after school should go.
No year groups. No red pen. Just the next thing.
LightMySky keeps a record of what a learner knows, topic by topic, and uses it to decide what they should do next. Every topic is a star: it lights when they show they know it and dims as the memory fades, because that is what memory does. Whatever is fading comes back before it is gone, and anything that depends on a missing piece waits until that piece is in place.
Nothing is arranged by school year. Topics are placed by what they need, so a learner who is ahead in one subject and behind in another is a normal case rather than a problem to explain. A session is a handful of questions, each chosen from what the learner has shown so far, and every one shows its working afterwards, right or wrong. Nothing is timed and nothing is marked in red: a wrong answer moves the next question, not a score.
Adults see the same sky the learner sees, plus the part a learner does not need: which subjects are moving, what is fading, and where five minutes after school would do the most good. It is free to read without an account; an account keeps progress across devices and lets one adult follow more than one learner.
Most gaps sit further back than they look.
Struggling with one thing usually means something earlier is missing. More practice on the thing that is failing will not find it.
- Compound Units
- Reading Distance-Time Graphs
- Predicting Motion Patterns
3,581 prerequisite links across 1,739 topics. Get one wrong and the next question drops to what sits under it, then keeps dropping until you get one right.
That is the difference between practice and progress. Repeating the failing question trains the frustration; finding the missing step underneath it removes the reason the question failed. A single miss is checked with a second question before anything is written down, because one bad answer on a good day proves very little.
Beyond the school day
Ready-made packs for what schools rarely teach. Switch one on for a learner, or download the file and edit it.
Where it leads
Every career here is mapped to the school topics it is actually built on, so “why do I need this” has an answer with a path in it.
Every subject in the library
16 subjects, 1,739 topics, each placed by what it needs rather than by the year it usually turns up in. Open a subject to see its areas in the order they build on each other.
- ScienceInsects & Minibeasts · Space Exploration · Animals of the World · Dinosaurs & Paleontology · Earth's Systems · Ecosystems & Habitats · Energy · Weather & Climate · Rainforests · Waves, Light & Sound · Forces & Motion · Space Systems & Earth's History · Volcanoes & Earthquakes · Matter & Materials · Ocean Life · Organisms & Life Processes · Polar Regions · Chemistry · Quantum & Modern Physics · Electricity & Magnetism · Thermal & Statistical Physics · Astronomy & Astrophysics · Scientific Inquiry · The Human Body · Genetics & Evolution · Biochemistry & Molecular Biology · Microbiology · Ecology & Conservation
- MathematicsCounting & Cardinality · Addition & Subtraction · Geometry · Measurement · Multiplication & Division · Fractions · Data & Statistics · Mathematical Thinking · Ratio & Proportion · Number Representation & Place Value · Algebra · Mechanics · Linear Algebra · Calculus & Analysis · Complex Analysis · Differential Equations · Probability · Discrete Mathematics · Abstract Algebra · Number Theory · Topology
Questions people ask
What is LightMySky?
A record of what a learner knows, across 1,739 topics in 16 subjects. Topics light up as they are learned, and dim as they are forgotten, so the next thing to work on is always visible.
Who is it for?
Any learner from age 4 to 24, and the parents, tutors and teachers who follow them. Topics are ordered by prerequisites rather than school year, so being ahead in maths and behind in reading is fine.
What does it cost?
Nothing. Every lesson, video and practice question is free to read, and an account is free as well. There is no card, no trial and no paid tier waiting behind the free one. The catalog is also published for machines to read, under the same terms.
Do I need an account?
No. Open any topic and start. Progress saves in that browser; an account keeps it across devices and lets you follow more than one learner.
What is on a topic page?
A lesson in plain language with drawn scenes, a video where a good one exists, and practice questions that show their working step by step. Some topics also carry a hands-on lab.
Is it safe for a child to use on their own?
Yes. There are no adverts, no chat, no strangers and nothing to buy. A child sees lessons, questions and their own sky, and an adult on the account can see everything the child did. The only thing a child can spend is Stardust, which is earned by answering and buys decorations for their sky.
How does it know what my child already knows?
It assumes everything well below their age, then checks as they practise. Whatever fails comes back, and anything built on it waits until the missing piece is in place.
What happens when a learner gets something wrong?
The next question drops to the topic underneath, and keeps dropping until one comes back right. A single miss is confirmed with a second question before anything is written down.
When does a topic come back?
Just before it would be forgotten. Every answer moves an estimate of how long that memory will hold, and review is timed against it rather than against a calendar. A topic answered confidently three times comes back in months; one that was a struggle comes back in days.
Does it follow the national curriculum?
Topics map to 7 frameworks, including the England national curriculum, Common Core and NGSS. The order comes from 3,581 prerequisite links, not from year groups.
Can I add my own topics?
Yes. A pack is a set of your own topics, lessons and questions, wired into the same prerequisite graph. Packs can be kept private, shared by email, or exported as a file.
Where does the material come from?
The taxonomy comes from the open Marble Skill Taxonomy: structure under ODbL, text under CC BY-SA 4.0. Lessons and practice questions are written by LightMySky. Quoting either is welcome with a link back.
Can I use it with an AI tutor?
Yes. The same graph is a public API, the whole catalog is published as plain text at /llms.txt and /llms-full.txt, and every public page will answer in Markdown when asked for it. Your model writes the words; the graph picks the topic.
Building an AI tutor? Start with the API quickstart. Sending an agent? Here is when to use this site, and how to call it.