Substack Moves Into Sponsorships and Enterprise Tooling After $100 Million Raise

Substack is expanding beyond its core subscription newsletter product into ad sponsorships, enterprise publisher tooling, and international operations. The company raised $100 million at a valuation of $1.1 billion, as reported by the NZ Herald.

Co-founder and chief operating officer Hamish McKenzie stated that the company has kept most of that capital in reserve while ramping up team growth: "The truth is, we really haven’t spent much of it yet. We’ve started hiring a bit more aggressively. We’ve started an international push. We have started to make a push into sponsorships as an additive but we haven’t spent on the really big fireworks yet."

Substack operates with 90 employees from its headquarters in San Francisco. The platform hosts more than 3 million newsletters, reaches tens of millions of registered readers, and counts 5 million paid subscribers, according to figures reported by the NZ Herald. That subscriber base puts it ahead of traditional digital publications such as The Wall Street Journal and The Washington Post, according to Britannica.

Direct Subscriptions and Creator Infrastructure

Founded in 2017 after participating in Y Combinator’s W18 batch, Substack provides infrastructure for writers, podcasters, and independent media operators to distribute content directly to inboxes and monetize through paid recurring subscriptions. The platform handles email delivery, content creation, audience analytics, and subscription management. Creators retain ownership of their intellectual property, subscriber payment relationships, and mailing lists.

While early growth centered on text-based newsletters, the platform has expanded into discussion threads, notes, chat channels, and audio hosting. Substack introduced podcast sponsorships to give audio creators commercial monetization tools alongside direct listener payments.

The engineering team works with a focused stack: TypeScript, JavaScript, Node.js, Express, and PostgreSQL on the backend, React on the web frontend, and Stripe for payment processing and subscription billing. Engineering leadership keeps the stack intentionally simple so a small team can support millions of readers and creators without layer-heavy infrastructure.

Founders and Background

Substack was founded by Chris Best, Jairaj Sethi, and Hamish McKenzie. The trio previously worked together at messaging service Kik Interactive.

• Co-founder and chief executive officer Chris Best earned a degree in Systems Design Engineering from the University of Waterloo in 2010. He co-founded Kik in 2009 and served as its chief technology officer through 2017. Best also angel invests in technology startups, including real-time database company Artie.
• Co-founder Jairaj Sethi completed a Bachelor of Mathematics at the University of Waterloo in 2011. He spent five years at Kik from 2012 to 2017 as principal developer and head of platform. Sethi also serves as an advisor to mental health platform Homecoming.
• Co-founder and chief operating officer Hamish McKenzie is a former journalist who studied English literature at the University of Otago and earned a master’s in journalism from Western University. He covered the tech sector for PandoDaily between 2011 and 2013, worked as lead writer at Tesla from 2014 to 2015, and consulted as an editorial advisor for Kik before teaming up with Best and Sethi. McKenzie authored Insane Mode, a book on Tesla, and has written How to Save the Media.

Two of the three founders possess software engineering backgrounds, and the company maintains an engineering-heavy leadership model where founders ship code directly.

Sponsorships, Enterprise Growth, and Product Shifts

Substack built its reputation on consumer subscriptions, but its current hiring plan reflects a deliberate commercial expansion into ad-supported revenue models and enterprise publisher setups.

The company is actively developing commercial sponsorship features for both newsletters and podcasts, hiring product leaders such as a Product Manager - Sponsorships and a Product Operations, Brand Partnerships specialist in New York. Engineering teams are supporting these commercial tracks by hiring a Full Stack Software Engineer - Sponsorships in San Francisco.

At the same time, the company is courting larger publishers and multi-author publications. The engineering team is building specialized features to support higher-volume publishers through a dedicated Full Stack Software Engineer - Enterprise role based in New York.

Editorial moderation and safety remain persistent operational priorities. The platform encountered public criticism in late 2023 and early 2024 over its moderation policies regarding extremist newsletters, as noted by Britannica. In response to ongoing platform governance demands, the company is recruiting trust and safety personnel, including a remote Standards & Enforcement Specialist.

Open Roles and Compensation

Substack lists 17 open positions across software engineering, brand partnerships, product management, people operations, and international community building. Most US positions follow a hybrid model between the San Francisco headquarters and New York, with select international roles in London and remote options.

Base salaries are transparent across engineering and business units. Software engineering roles typically start at $140,000 and top out at $260,000 per year, while leadership roles in strategic business operations and human resources scale up to $300,000.

See all open roles at Substack