ShelfSparkWrite the one they're waiting for
Test the book you're itching to write against the one you suspect you should. Walk into your next pitch with readers already on a list.
Audience testing for books
Know if your book has readers before you write it.
ShelfSpark puts your idea in front of the people most likely to buy it, dressed as a finished book. Then it counts the hands that go up. Proof of demand arrives in days, long before a manuscript does.
Harbor Lane BooksSponsoredA Novel
The Salt Archive
M. Okafor
A lighthouse keeper's daughter finds her mother's letters sealed inside the walls, each one addressed to a woman who never existed.
Coming 2027Be first to read itNotify me
An illustrative campaign. The book is imaginary; the readers it reaches are not.
How it works
From premise to proof in about a week.
No manuscript, no cover budget, no guesswork dressed up as instinct. Just a clear read on who wants the book.
Pitch the idea
Send the premise along with a couple of comparable titles. A strong paragraph is plenty to work from.
We build the campaign
ShelfSpark designs cover-quality ads and a pre-order page, then runs them on Facebook and Instagram to readers of your genre.
Read the signal
Sign-ups arrive from readers who say they'd buy it. Our positioning report shows which hook landed and where your audience lives.
Who it's for
Anyone who has to bet on a book.
Every acquisition is a wager on an audience nobody has met yet. ShelfSpark introduces you first.
Bring evidence, not adjectives
A proposal backed by real sign-ups reads differently on an editor's desk. Show the appetite instead of describing it.
Size it before you sign it
Gauge demand before the offer goes out, then launch knowing exactly which angle pulls readers in.
Why we built it
Made on the acquisitions side of the table.
“I've spent years reading proposals and trying to picture the reader on the other end. Publishing runs on hunches because testing a book used to mean writing it first. That's the part ShelfSpark fixes.”Phil Marino, Founder
Early access
Test your next book first.
We're opening ShelfSpark to a small founding group this winter. Leave your email and we'll reach out when your spot is ready.