Spines Raises $64 Million to Automate Book Publishing With AI Agents

AI publishing startup Spines has secured $64 million in fresh capital to scale its agent-driven platform for authors, the company said Monday.

The package splits into two parts: a $29 million Series A-1 equity round led by Zeev Ventures, with participation from Aleph, NordStar, M-Fund, LionTree and angel investor Dan Senor, plus a $35 million "non-dilutive growth financing facility" from Twelve, a credit-focused investment management firm. The company declined to disclose its post-money valuation.

Spines, which operates from offices in Israel and New York, also announced its AI-powered services have pushed it to a $50 million annual revenue run rate — 400% year-over-year growth. The company has published more than 8,000 authors across roughly 12,000 titles, founder and CEO Yehuda Niv told Fortune. About 400 new writers sign up each month.

What does Spines actually sell?

Spines is a "hybrid publisher." It targets authors who can't land a traditional publishing deal, or who want more control and a bigger royalty split than commercial houses offer. Authors pay an upfront fee, the publisher takes a cut of sales, and the author gets more support than pure self-publishing provides.

Spines calls itself an "operating system for authors." Writers upload a finished manuscript, and specialized AI agents handle editing, proofreading, formatting, cover design, metadata, ebook and print-on-demand files, and distribution to more than 100 channels, including Amazon, Barnes & Noble, and Baker & Taylor. Authors can generate an audiobook with a synthetic narrator or a clone of their own voice, then translate both the book and the audiobook. Spines currently offers seven target languages and plans to reach 20 within six months. After publication, the platform tracks royalties and runs marketing campaigns.

Niv argues the agents beat the freelancers authors typically hire. Of roughly 10,000 authors he published in Israel, he said, every one had the same complaint: "The cover designer didn't have time to read my book." Spines' cover agent reads the manuscript, researches which retail categories give the book its best shot, and designs the cover to match those metrics.

The agents also compress timelines. Traditional publishing takes many months to more than a year from manuscript to store shelves; Spines brings that down to weeks.

How much do authors pay?

Publishing packages start at about $3,000 and run to $20,000 for a premium tier that publishes a book in three languages, each with an audiobook. Most authors pick a mid-tier bundle costing $5,000 to $7,000, Niv said. Spines recently raised its royalty split so authors keep 80% of net royalties, up from 70%. It reports royalties monthly — versus the twice-yearly or annual statements common in the industry — and is working toward weekly and eventually real-time reporting.

Niv insists the platform only publishes books "100% written by humans" and uses software to weed out AI-generated manuscripts. "We are not here to replace [authors] with AI," he said. Spines exists to "empower" human writers.

Copyright questions remain, particularly around AI-designed covers. U.S. courts and the Copyright Office have held that images made entirely by AI can't be copyrighted. Niv said Spines licenses its image-generation tools and passes that license on to authors — often broader, he argued, than what human illustrators grant, since illustrators usually keep the copyright and license the image only for the book cover.

Where does the money go — and who's next?

Spines employs roughly 350 people, but only about 50 work in R&D. Most of the rest handle customer success and support, helping authors with decisions software can't make. "Our AI agent designed for you three amazing covers, but eventually you have to choose one," Niv said. "For an author, that's an emotional decision."

Today Spines sells directly to authors without a traditional publisher. Niv said the company is in early talks with one of the Big Five U.S. publishers about a partnership that would deploy Spines and its AI agents to help run that house's services.

"Spines has all the ingredients to become the category leader in the next generation of publishing," Oren Zeev, founding partner of Zeev Ventures, said in a statement.

Niv said Spines will use the debt facility to fund growth and the equity to build out its product and expand beyond the U.S. into the U.K., Canada and Australia. He's targeting 200% to 300% annual growth. Most staff work in Eastern Europe, the U.S. and Latin America, while R&D and management are based in Herzliya, Israel.

The backstory: about 15 years ago, mid-way through a master's degree in electronic engineering, Niv published his own book and concluded "the publishing process is completely broken." He bootstrapped Niv Publishing, which he says became Israel's largest publishing house at roughly 1,200 titles a year. Roughly six years ago, he said, he realized AI would eventually "make every [traditional] publishing company on the planet irrelevant." He founded Spines in 2021. A Big Five deal, if it closes, would test that thesis from the inside.