A reader with five games on what you just read
NeuroSprint is a reader for dense material: papers, documentation, contracts, textbooks. A highlighter pacer keeps your place while you read. Then five short games get the passage back out of your head — write down what you remember, catch the word that was changed, fill the gaps, explain it in your own words. Two minutes, and you know whether it stuck.
Free. No account needed. Your documents stay in your browser.
Or take the two-minute reading speed testSample passage · How a lighthouse lens works
An open flame throws light in every direction, so most of an old lighthouse lamp was wasted on the sky and the rocks. One lens wide enough to gather it would have been impossibly heavy. Augustin Fresnel’s answer rests on one fact: glass bends light only at its surface, and the bulk is dead weight. He kept the curve, cut it into concentric rings and stepped the glass back: a thin lens that still throws one level beam to the horizon.
Explain it back
Why could Fresnel throw away most of the glass, and what problem did that solve?
Your answer
Glass only bends light at its surface, so everything behind the curve is dead weight. He kept the curve as a set of rings and stepped the rest back, which made the lens thin.
Passed · 82/100
You have the mechanism: the bending happens at the surface, so the bulk can go. You stopped short of the problem it solved, which was a lens too heavy to build and a flame wasting most of its light.
§ 01 The moment
Your eyes did their job. They crossed every line, in order, and you remember turning the page. But somewhere around the second paragraph your attention went to tomorrow’s meeting, and the words kept sliding past without you. So you go back to the top and read it again, highlighter in hand this time, and it feels like progress.
It mostly isn’t. Rereading and highlighting feel productive because they are easy, and they are easy because they ask nothing of you.1 The thing that works is less comfortable: look away from the page and try to say what it said.
NeuroSprint makes the first read easier to stay with. Then it makes you do the uncomfortable part.
§ 02 How it works
Paste anything: the methods section, an API reference, clause 14 of the lease. Or open a PDF and pick the part of the page you actually want to read.
Your documents are kept in your browser. They are not uploaded.
Paste textOpen a PDF
An open flame throws light in every direction, so most of an old lighthouse lamp was wasted on the sky and the rocks. One lens wide enough
Kept in this browser · not uploaded
A highlight moves through the text, in place, at the pace you set. Slow it down for the hard paragraph; let it run through the boilerplate. A ruler or a line mask quiets the rest of the page.
It keeps your place and holds a steady pace. That is all it claims to do.
Augustin Fresnel’s answer rests on one fact: glass bends light only at its surface, and the bulk is dead weight. He kept the curve, cut it into concentric rings and stepped
− 180 wpm + AaAaAa
When the passage ends, five games take it from you — each one a different way of getting the same thing back out.
They are short on purpose: two minutes, not a revision session. Blurt, Spot the swap, Sprint and self-grading are free. AI reviews and diagrams come with a free weekly allowance.
Sprint · fill the gaps
Glass bends light only at its surface, and the bulk is dead .
Explain it back
Passed · 82/100
You have the mechanism. You stopped short of the problem it solved.
Map it
§ 03 Explain it back
The app picks a pointed question about the passage you just read: why it works this way, what the constraint is, what the claim rests on. You answer in your own words. An AI reviewer, briefed to behave like a demanding but fair senior tech lead, grades it against the passage: pass or fail, an accuracy score from 0 to 100, and two sentences on what landed and what was missing.
The passage
Steel and concrete grow when they warm. Over a hot afternoon, a bridge deck a few hundred metres long can lengthen by several centimetres, and nothing you build will hold it back; restrained, the deck would buckle or crack its own supports. So engineers leave a gap and span it with an expansion joint, often a set of interlocking steel fingers, that lets the deck slide. The joint is not there to stop the movement. It is there to give the movement somewhere to go.
The question
Why leave a gap, instead of building the deck strong enough to stay put?
Answer A · the skim
Expansion joints are gaps in a bridge that deal with the expansion of the materials, so the bridge stays safe.
Not passed · 35/100
This says that joints exist, not why resisting the movement fails. What happens to a deck that is held still while it heats up?
Answer B · in their own words
Because you can’t out-muscle thermal expansion. If a long deck is pinned at both ends while it heats up, the force goes into the structure, and it buckles or cracks its supports. The gap lets it slide instead, like leaving slack in a cable.
Passed · 94/100
Cause and consequence are both right, in your own words, and the slack-in-a-cable comparison holds. The only thing you left out is the scale: several centimetres over a few hundred metres.
Answer C · the copy-paste
Steel and concrete grow when they warm. Over a hot afternoon, a bridge deck a few hundred metres long can lengthen by several centimetres…
Not passed · 0/100
That is the passage, word for word, so there is nothing of yours to grade. Look away from the page and tell me why the gap is there.
Illustrative example. The reviewer’s exact wording varies. Try it on something you’re reading
§ 04 Reading tools
Nothing here is clever. It is the set of small things that make a hard page easier to stay on.
§ 05 The research
The average adult reads English non-fiction silently at about 238 words per minute, and fiction at about 260.6 Courses and apps that promise to double or triple that are selling a trade they do not mention: past your natural pace, more speed means less understanding. The bottleneck in reading is not how fast your eyes move. It is how fast you can recognise words and put the meaning together.5
So the pacer here has no hidden ambition. It keeps your place and holds a steady pace that you choose. If the honest pace for a contract is 140 words a minute, that is the right pace.
What the research does support is less glamorous. Testing yourself on what you read beats reading it again.2, 3 In a major review of study techniques, practice testing and spreading practice over time were rated the most useful, and rereading and highlighting among the least.1 Explaining material to yourself as you go improves understanding.4
NeuroSprint itself has not been tested in a controlled study. It is built around techniques that have.
Promises we will not make:
What we offer instead: Understand the page in front of you.
These studies are about the techniques, not about this product.
§ 06 Browser extension
NeuroSprint Reader is a free browser extension: a reading ruler, line focus, typography comfort settings, a page tint, a guided pacer and read-aloud, on any web page — and then the games. Blurt, Spot the swap and Sprint run in a panel beside the page, on the article you have just read. No account. Nothing leaves your browser.
Coming soon to the Chrome Web Store
It is built and heading to the Chrome Web Store. Want a note when it is out? E-mail us and we will write once, when it is live.
No account. Nothing leaves your browser.
Why bridges have gaps in them
Steel and concrete grow when they warm. Over a hot afternoon, a bridge deck a few hundred metres long can lengthen by several
§ 07 Pricing
$0
An AI action is one graded “Explain it back” answer or one generated diagram. On Pro, the questions written for a round of Explain it back count as one more.
Open the readerEverything in Free, plus:
Lifetime = for the lifetime of the product. Includes up to 10 AI actions a day.
Payments are processed by Dodo Payments, our merchant of record. Taxes may apply at checkout. 14-day refund on your first purchase.
§ 08 Questions
No. NeuroSprint is reading software. It is not a medical device, and it does not diagnose, treat or manage ADHD, dyslexia or any other condition. It is not a substitute for advice from a qualified professional. It is a tool for anyone who wants to check that what they read actually went in.
No. Text you paste and PDFs you open are stored in your browser and are not uploaded. There is one deliberate exception: when you ask for an AI review or a diagram, the excerpt you are working on (up to about 4,000 characters), the question and your answer are sent to our server and passed to Anthropic’s API so they can be graded or turned into a diagram. On Pro, opening Explain it back also sends that round’s passages (up to about 10,000 characters), so a question can be written for each. We do not store that content; we keep only a usage counter per user, so the limits work.
Only what that one action needs: the passage excerpt, the question you were asked and the answer you wrote. It does not see your library, the rest of the document or your earlier answers. It is instructed to grade like a demanding but fair senior tech lead: against the question that was asked, in your own words, with no credit for vague answers and none for pasting the passage back. Like any AI it can be wrong, so treat the note as a sharp second opinion, not a ruling.
Anthropic, under its commercial terms, does not use API content to train its models and deletes it within 30 days unless it must keep it longer for legal or safety reasons.
No. Pasting text, the pacer, the ruler, themes and the recall games (Blurt, Spot the swap, Sprint) all work without one, and everything stays in your browser. A free account (Google or an e-mail sign-in link) adds two things: your library progress follows you across devices, and you get 3 AI actions per week. An AI action is one graded Explain it back answer or one generated diagram.
Free covers reading pasted text with the pacer, ruler, themes and presets, without limits; the recall games Blurt, Spot the swap and Sprint; the first 10 pages of each PDF, with up to 3 documents in the library; self-grading; and, with a free account, library progress that follows you across devices and 3 AI actions per week.
Pro adds AI reviews and diagrams without the weekly cap (fair use: up to 30 a day), full-length PDFs and an unlimited library, Pure Text reflow for PDFs, a question written for each passage in Explain it back, and your diagram gallery synced across devices. Lifetime is a one-time payment for the same features, and includes up to 10 AI actions a day.
Yes. If it is your first purchase, e-mail support@getneurosprint.com within 14 days and we will refund it.
Yes. Cancel whenever you like and you keep Pro until the end of the period you have already paid for. Lifetime is a single payment, so there is nothing to cancel.
Any modern desktop or mobile browser. The interface is in English, and you can read text in any left-to-right language.
No. The research on speed reading is clear that, past your natural pace, speed is paid for with comprehension. The pacer is there to keep your place and hold a steady pace that you choose, and slower is often the right choice for hard material. What NeuroSprint adds is the step after reading: checking what you understood.
NeuroSprint is independent software, funded by its subscribers. There are no ads and we do not sell data.
Free. No account needed. Your documents stay in your browser.