Feedback students can actually see — and act on
CoMarker reads the way a teacher does: sentence by sentence, against your rubric and your task. Here is everything under the hood.
Everything you need to mark faster and fairer
Students can check their own work — independently
Submit your own essay and instantly see every sentence highlighted — colour-coded, explained, and tied to the rubric.
Find out exactly what earned marks, what didn't, and what to fix — before the final submission.
No waiting. No guessing.
Sentence-level highlights
Colour-coded spans show exactly which sentences earned or lost marks.
Grades against your task
Marks are tied to the actual task or stimulus sheet you set — not a generic prompt.
Your rubric, your criteria
Upload any rubric and CoMarker maps every comment back to your criteria.
A full class in minutes
Batch a whole set of essays and get consistent marks back fast.
Actionable feedback
Specific, criterion-linked comments students can actually use to improve.
Teacher-in-the-loop
Review and override every grade and comment before anything is released.
Built for K-12
Designed around how teachers actually mark, from primary through senior years.
Privacy-first
Student work is handled with strict access controls and clear retention.
Built to mark the writing, not skim it.
Most AI graders spit out a number and a paragraph of generic advice. CoMarker reads the way you do — sentence by sentence — and ties every highlight back to a specific rubric criterion.
- Sentence-level colour coding shows students precisely where they hit or missed the mark.
- Graded against your task sheet, so feedback reflects what you actually asked for.
- Every comment maps to a criterion, making moderation and feedback conversations easy.
Hover any highlighted sentence in the example to see the criterion and feedback.
Climate change is one of the most urgent challenges facing our generation, and its effects are already visible worldwide. According to NASA, global temperatures have risen by roughly 1.1°C since the late 19th century. This warming has caused ice caps to melt and sea levels to rise, which is bad for lots of places. Many scientists think we should do something about it soon. In conclusion the world is getting hotter and thats a big problem for everyone. Governments should invest in renewable energy because it reduces emissions. Also plastic is a problem and pollution too. By acting now, we can protect ecosystems and build a more sustainable future for the next generation.
Highlights that point to the exact sentence
Instead of a paragraph of generic advice, CoMarker marks each sentence green, amber, or red and explains why — so students see precisely where they earned or lost marks.
Marked against the task you actually set
Upload your task or stimulus sheet and CoMarker grades in context. A brilliant essay that ignores the question is marked as exactly that.
Your rubric drives every comment
Bring your own rubric. Every highlight maps back to a named criterion, which makes moderation, reporting, and feedback conversations straightforward.
You are always the final marker
CoMarker drafts; you decide. Adjust any grade or comment and release feedback only when you are happy with it.
How it works
Three steps from a stack of essays to feedback that lands — with a teacher in the loop the whole way.
Upload the task and the work
Drop in your rubric and the actual task or stimulus sheet, then add the class set of essays — PDFs, docs, or scans.
CoMarker marks against your criteria
Every essay is graded sentence-by-sentence against your rubric and the task you set, with colour-coded highlights explaining each mark.
You review, adjust, and release
You stay in control. Skim the highlights, tweak any grade or comment, and release polished feedback students can actually act on.
From marking marathon to a quick review
| Without CoMarker | With CoMarker | |
|---|---|---|
| Turnaround for a full class | A weekend of marking | Minutes, then a quick review |
| Feedback students get | A grade and a vague comment | Sentence-level, colour-coded highlights |
| What the marking is based on | A generic AI prompt | Your rubric and your actual task sheet |
| Consistency across the class | Drifts as you tire | Same criteria applied to every student |
Mark your next class in minutes.
Start free — no credit card. See sentence-level feedback on your own essays today.