Read everything.
Faster.

RSVP (Rapid Serial Visual Presentation) shows text one word at a time in a fixed spot on screen, so your eyes never have to travel along a line. You choose the speed: Spark Read runs from 100 to 1000 words per minute. For reference, the average adult reads non-fiction silently at about 238 WPM (Brysbaert, 2019). Spark Read pairs RSVP with ORP highlighting and short pauses at punctuation.

Sources: Brysbaert (2019), Journal of Memory and Language

ORP (Optimal Recognition Point) is the letter your eye should land on to recognise a word fastest. Eye-tracking research puts that point slightly left of a word’s centre (O’Regan & Jacobs, 1992). Spark Read highlights it in red, about a quarter to a third of the way into each word, and keeps it in the same place on screen, so your eye never has to hunt for where the next word starts.

Sources: O’Regan & Jacobs (1992), J. Exp. Psychology: Human Perception and Performance

It can, and the research is clear about when. At ordinary reading speeds, comprehension with RSVP is about the same as reading a page. As speed rises, comprehension and memory fall, and there is little evidence that people can double or triple their speed without losing understanding (Rayner et al., 2016). Going back over text matters too: blocking it lowered comprehension in an eye-tracking study (Schotter, Tran & Rayner, 2014). That is why Spark Read pauses at sentence and clause boundaries, rewinds 10 words with one tap, and leaves the pace to you. Start near your normal speed and raise it gradually.

Sources: Rayner et al. (2016), Psychological Science in the Public Interest; Schotter, Tran & Rayner (2014), Psychological Science

Spark Read handles PDF, EPUB, DOCX, TXT, and Markdown files. You can also import web articles by pasting a URL, share from any app via the native share sheet, or type and paste text directly. All parsing happens on your device — your documents never leave your phone or browser unless you opt into cloud sync.

Yes. Sign in with Apple or email magic link and your documents, reading position, and session history all sync via Supabase. Start a long PDF on your laptop, finish it on the train. The free tier includes 5 cloud documents; Pro expands to 50 and Lifetime is unlimited.

A Pro and Lifetime feature that summarizes long PDFs and articles into a focused condensed version before reading. Choose your preferred AI provider — Claude, GPT, Gemini, Grok, or DeepSeek — and Spark Read returns the condensed text as a new document in your library. The original is untouched.

No. The full RSVP reader, all import formats, ORP highlighting, analytics, and focus mode work locally without an account. Sign in with Apple or email magic link only if you want cloud sync, AI condensing, or to upgrade to Pro/Lifetime.

Yes. The core RSVP reader is completely free: import documents in any format, read at adjustable speeds with ORP highlighting, use intelligent pacing, focus mode for ADHD/dyslexia, reading analytics, and 5 cloud documents — all without an account. Pro ($3.99/mo or $29.99/yr) adds 50 cloud documents, AI condensing, CSV analytics export, and priority support. Lifetime ($44.99 one-time) makes cloud storage unlimited and bundles all future features.

Yes. Spark Read is offline-first. All documents are stored locally on your device using IndexedDB, and the entire app works without an internet connection. Cloud sync is optional and only activates when you sign in. The web app can also be installed as a PWA for a native-like offline experience.