Spritz: the idea that made this popular
Spritz appeared in 2014 with a demonstration that spread everywhere: a small box, one word at a time, one letter in red. The contribution was not the idea of showing words serially — laboratories had done that since the 1970s — but the alignment. By positioning every word so that the recognition point falls in the same physical spot, and marking that spot, Spritz made the stream comfortable rather than jittery.
Spritz itself is a licensed technology rather than a product you use: it appears inside other companies' apps. That is the practical limitation. You cannot simply open your PDF in "Spritz"; you use whatever app has licensed it, with whatever that app supports.
Spreeder: the training-course model
Spreeder comes from the other tradition — speed reading as a skill to be drilled. Alongside an RSVP reader it offers courses, exercises and progress tracking, on a subscription. If you believe reading speed is a trainable skill and want structure and accountability, that is a coherent thing to buy.
It is worth pairing that with what the research says about the underlying claims, because several of the classic exercises target habits that turn out not to be waste. We go through that in does speed reading work?. The short version: the drills that build reading volume help, and the ones aimed at suppressing regressions or the inner voice are working against comprehension rather than for speed.
The rest of the field
Beyond those two there is a long tail: browser extensions that spritz the current page, mobile apps of varying polish, and a number of open-source readers. They differ mostly in three ways — where the text can come from, whether the reader is honest about its limits, and what happens to your files.
What actually differentiates an RSVP reader
The word-flashing part is a weekend of work; every one of these tools does it. What separates them is everything around it.
- Where the text comes from. Pasting is table stakes. Opening a PDF or an EPUB is where most tools stop, because extracting readable text from a PDF is genuinely hard. If you mainly read papers and books, this is the only question that matters.
- What happens to your file. Some readers upload your document to a server to convert it. If the file is a book you bought, a draft, or anything from work, that is a decision you should make knowingly rather than by default.
- Whether the focus letter holds still. Sloppy alignment is the difference between comfortable and headache-inducing, and it is visible within ten seconds of a demo. Watch the coloured letter, not the words.
- Whether you can go back. Every RSVP reader loses the ability to glance backwards. A serious one gives you a step-back control and a draggable progress bar to compensate.
- Structure. Does it know where the paragraphs and chapters are, or is your book one 90,000-word ribbon? A short pause at a paragraph break is most of what makes the stream feel like prose.
- The price of finding out. Anything that needs an account or a card before you can read one page is asking you to commit before you know whether the method suits you at all.
Where Readly sits
We should be plain about our own bias here, since this is our website. Readly is free, needs no account, and opens pasted text, PDFs, EPUBs and article links. Files are parsed in your browser and never uploaded — only a pasted link is fetched by our server, because it has to be. It has the fixed focus letter, a step-back control, a draggable scrubber, paragraph pauses, optional stops at chapter starts, and speeds up to 1200 words per minute for people who want them.
What it does not have: training courses, a mobile app, comprehension drills, or a saved library across devices — that last one is being built. And we will not tell you that you can read at 1000 words per minute and understand everything, because you cannot, and a reader that pretends otherwise is optimising for the demo rather than for the reading.
How to choose in ten minutes
- Open your own text in each candidate — not the demo passage they chose.
- Watch the highlighted letter. If it moves, walk away.
- Try the file format you actually read most. A tool that handles paste but not your PDFs solves nothing.
- Push the speed until you lose the thread, then come back 100 words per minute. That is your number, and it is the only benchmark that means anything.
- Check what happens to your files, and what happens if you stop paying.
If you want the mechanics behind all of these tools first, start with what is RSVP reading?