Substack

Substack’s core revenue model is plainly stated across multiple official sources: the company takes 10% of subscription revenue while writers keep 90%, with no fees charged to readers. The company has publicly disclosed its now-discontinued Pro program which took 85% in year one before reverting to 10%. The iOS in-app purchase structure, where Apple takes 15–30%, is documented in official support articles. A native sponsorship pilot launched in December 2025 was publicly reported, though announced through a paywalled creator interview rather than an official company statement — a transparency gap worth watching as the advertising model develops.

Substack makes money only when writers make money through subscriptions. The 10% commission structure means the company’s revenue grows in direct proportion to writer success. The company’s algorithm is explicitly stated to optimise for subscriptions and paid conversions rather than time spent or engagement metrics. The discontinued Pro program created temporary misalignment (85% in year one) but ended in 2022. The iOS payment structure creates friction but does not fundamentally alter the commission-based alignment between platform and creator success.

Substack provides comprehensive self-serve data export: full subscriber lists as CSV files including email addresses, subscription status, payment information, and engagement metrics; complete content archives as downloadable zip files. The company explicitly states that writers own their content, subscriber list, and payment relationships and can take all of it on departure. Cancellation is self-serve through account settings with benefits continuing until the billing period ends, and a pause option is available. Migrating paid subscriptions requires a Stripe account transfer, which is more involved than moving free lists, but this reflects Stripe’s payment architecture rather than deliberate Substack lock-in. The iOS in-app purchase limitation — where billing relationships for Apple-paying subscribers cannot be transferred — is an Apple-imposed constraint documented transparently in Substack’s own support articles, not a Substack captivity design.

Substack’s Notes feature includes push notifications for likes, restacks, replies, and mentions that are automatically enabled. Multiple writers have documented experiencing compulsive engagement mechanics and criticised the platform’s transformation toward social media dynamics. However, the company’s stated algorithmic optimisation is for subscriptions and paid conversions rather than time spent or endless scrolling. No internal documentation or independent research was found confirming deliberate calibration of mechanics to defeat user judgment or extend use beyond genuine value. The engagement mechanics exist and benefit the platform but the evidence stops short of proving systematic engineering against the user’s ability to disengage.

Substack serves both readers and writers, but the evidence shows a consistent pattern of prioritising writer revenue relationships — including controversial writers — over reader safety. The Substack Pro program paid six-figure advances to writers accused of producing anti-trans and anti-vaccine content while taking 10% of revenue from harmful content including newsletters earning the company an estimated $250,000 annually from anti-vaccine misinformation. When prominent writers threatened to leave over Nazi and racist content, the company initially refused to remove it, stating it ‘didn’t like Nazis either’ but would not moderate as a matter of policy. The company removed only five Nazi-affiliated accounts after sustained pressure. Co-founder Hamish McKenzie defended controversial writer advances by arguing that a hero can be thought a villain. Multiple marginalised writers documented leaving the platform specifically because Substack chose to financially support writers who targeted their communities. The December 2025 introduction of native sponsorships adds advertisers as a third party, creating a new tension that is not yet resolved by track record.

Substack was presented with documented evidence of at least 16 newsletters with overt Nazi symbols and explicitly stated it would not proactively remove Nazi content, with the co-founder saying ‘we don’t like Nazis either’ but refusing to commit to removal as policy. CEO Chris Best declined to state whether overtly racist content (‘all brown people are animals’) would be removed when directly asked in a recorded interview. The company generates at least $2.5 million annually from five anti-vaccine newsletters ranking in the top 20 of its politics category, taking 10% commission. Independent research found that searching COVID-19 on Substack surfaced primarily misinformation sources, with eight of ten top results being conspiracy content. The company removed five publications after sustained pressure but explicitly stated it would not change its content policy or proactively remove neo-Nazi content. This represents a documented pattern of non-intervention as policy stance, not isolated incidents.

Substack raised $100 million in Series C at a $1.1 billion valuation in July 2025, bringing total funding to approximately $190 million across six rounds. Primary investors include Andreessen Horowitz (holding over 25% post-Series B with board representation), BOND Capital, and The Chernin Group. The company achieved unicorn status despite revenues of approximately $45 million annually. A 2023 community funding round issued non-voting Shadow Shares to over 6,000 writers and readers, providing economic upside without governance rights. The company reached positive cash flow in Q1 2025, reducing immediate extraction pressure, but the valuation relative to revenue and the investor profile create return expectations that the December 2025 advertising pilot — announced four months after the Series C — may be an early response to.