CastReader — AI Explain - Listen to articles, Kindle & PDFs — and understand them
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CastReader reads web articles, Kindle & PDFs aloud in natural voices — and explains the hard parts as it reads. Read & Explain turns dense passages into plain language and marks up the page like a tutor with a highlighter, so you don't just hear it, you get it.
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CastReader
Hey everyone — Vin here, solo maker behind CastReader. Today's launch is the feature I'm most excited about: Read & Explain.
You know the problem with most read-aloud tools — they free up your eyes, but your brain still can't keep up. Hit a dense doc or a hardcore explainer and the voice just drones on word for word; by the end your head's mush and you're rereading it yourself anyway.
So I built Read & Explain into CastReader. Instead of reading verbatim, it explains as it goes — all in sync with the audio:
It explains, not just narrates — breaks dense, convoluted passages into plain language so they click by ear.
It marks up the page as it talks (my favorite part) — a virtual pen moves across the original text in sync with the voice, circling and highlighting the key bits, like notes by hand. Light touch, never covers the text; your eyes follow the pen, so you stop drifting off mid-listen.
Synced subtitles — every line of explanation shows word-by-word, so you read and listen at once.
The way I think about it: it's not an AI summary that hands you a detached block of text — it's more like a tutor sitting next to you with a pen, explaining while you both stay on the same page. You're anchored to the source, not a summary that floats off on its own.
It works on web articles, Kindle, and PDFs, in 40+ languages.
One thing I'd genuinely love your take on: when something's dense, do you want it explained inline like this — or do you just want a clean summary and move on? Happy to answer anything in the comments.