Kobo rejects 45% of self-published books amid AI flood

Rakuten Kobo turned away 45% of the titles submitted to its self-publishing platform, Kobo Writing Life, in 2025. Chief executive Michael Tamblyn attributed more than 80% of those rejections to manuscripts he described as "manifestly AI-generated and of very poor quality." In total, hundreds of thousands of submissions were rejected.

The figures highlight the mounting economic cost of generative AI on digital marketplaces. Platforms once theorised about a flood of cheap machine-made text, but they are now sorting through it in bulk. This deluge of low-value content threatens to degrade digital catalogues, forcing companies to expend significant resources on gatekeeping.

Kobo has opted to police submissions by measuring quality rather than certifying origin. Tamblyn acknowledged that the AI-detection software the company evaluated regularly misidentifies human writing as machine output, and vice versa. A manuscript that reads as cheap and mass-produced is turned away, regardless of whether its provenance can be definitively proven.

This stance is now codified in Kobo's terms of service. A help page refreshed in May lists grounds for rejection, including titles that are too short, poor translations, excessive prices, and wholly or partly AI-generated content. The company also reserves the right to use AI tools to read and analyse submitted texts, while explicitly stating it will not use the books to train generative AI systems.

The strategy contrasts with the route taken by Amazon’s Kindle Direct Publishing. Since September 2023, Amazon has required authors to declare AI-generated text, images, or translations at upload, though AI-assisted work remains undeclared. Kobo has chosen outright refusal over a disclosure form to address the same systemic pressure.

However, this aggressive filtering carries an economic toll of its own. Kobo has not disclosed how many legitimate human authors were caught in the net. As platforms deploy blunt quality controls to combat the rise of machine-made "workslop", the cost of a saturated market is increasingly borne by genuine writers.