Firebrat is for anyone who'd rather listen than stare at a page for hours — but it was designed first for people who find sustained reading of technical material genuinely difficult.
I'm dyslexic. Sustained silent reading — the kind a 600-page technical textbook demands — is exhausting and genuinely painful for me in a way it isn't for most people. Words swim. Lines get lost. A single dense paragraph about, say, SDRAM timing parameters can take several passes to actually land.
Listening is different. Spoken language is something I process well, fluently, for hours. It's how I actually get through dense material — podcasts, audiobooks, lectures. The problem is that technical books were never written to be read aloud. They lean on diagrams, register tables, and equations that a plain text-to-speech pass either skips entirely or reads out as meaningless noise ("t sub C K equals one over f...").
So the book stayed unread, or I read it slowly and painfully, or I found some workaround that lost half of what mattered. Firebrat exists because none of those were good enough.
The goal was never "add text-to-speech to a PDF reader." It was: let the narration carry the reading load I struggle with, while the figure or formula the narration is currently describing stays right in front of me, highlighted, exactly when it's relevant — and let me freely look at anything else on the page without breaking that flow.
Dyslexic readers, first and specifically. But the same design choices help a much wider set of people:
Concretely, in the app itself, not as an afterthought:
I'm not trying to speak for every dyslexic reader, or every person with a different relationship to text than mine — disability and reading difficulty aren't monolithic, and what helps me won't help everyone identically. What I can say is that this is a real tool, built to solve a real, specific, personal problem, released under a permissive-enough copyleft license so that anyone who wants to point it at their own technical book — or fork it and adjust it for how they read best — can.
For novels, a single narrator can make a conversation hard to follow, which matters most for readers who already find text difficult. Firebrat now has a second way to narrate fiction: every character gets a distinct voice, and lines are spoken with the emotion the scene calls for.
It needs a GPU. The large models run one at a time: first the casting step for every queued book, then the audio step book by book. The how it works page shows the stages.
Honest status. The casting stage has been run on real novels, and the stages are covered by offline tests. The new voice stage (Qwen3-TTS) has not yet been verified end to end on real books: it may need tuning after the first listen. Treat this mode as a preview, and use the community library only for books whose audio you have actually listened to.