When the internet runs on API, and APIs run on caffeine, broken docs and busted SDK become more than just an engineering headache, they become a tax on innovation. That’s the world Fern walked into in 2022. A world where API companies were taping documentation and SDKs together, hoping things stayed in sync long enough to avoid another “oops” in production. But hope isn't a strategy and Fern knew it.
This week, Fern, officially Birch Solutions Inc., just raised a $9M Series A led by Bessemer Venture Partners with continued backing from Y Combinator, and it’s not hard to see why. Since going live in 2023, they’ve landed 150+ enterprise customers including Square, Webflow, Intercom, and ElevenLabs. And not by playing safe. By building fast, solving deep, and treating developer experience like a product, not a checkbox.
Credit where it's due: Danny Sheridan, Deep Singhvi, and Zach Kirsch aren’t just the founders, they’re engineers who’ve felt this pain at Palantir and AWS. They didn’t build Fern for VC decks or TechCrunch clout. They built it because keeping SDKs and docs in sync shouldn’t feel like babysitting a toddler with a sugar rush.
Fern’s stack hits where it matters. Their AI-powered SDK Generator spits out code in seven languages (and counting), automatically pushes to GitHub, npm, and PyPI, and doesn’t flinch when your API changes for the third time this week. Their interactive docs don’t just look good, they include versioning, SSO, RBAC, and an integrated playground, so your users actually use them.
And they’re not slowing down. With this new round, they’re doubling down on AI. Ask AI, dropping Q3, will let developers talk to documentation like it’s a senior engineer who actually responds. After that? Model Context Protocol, turning APIs into something your AI agents can understand without a translator.
This isn’t dev tools as usual. It’s a play for the future. One where software agents will be shipping code at 3 AM, and your SDKs better be waiting for them with clear docs and zero guesswork.
If you’re building public APIs and still hand-coding your SDKs and docs, Fern isn’t just your next tool. It’s your missing infrastructure. And if you’re an engineer who’s ever muttered “it worked yesterday” while digging through out-of-date API docs, you already know, this is the fix we’ve been waiting for.
Props to Danny, Deep, and Zach. Props to Lindsey Li and the crew at Bessemer for betting on engineers building for engineers. And to the folks at YC, you saw this early. Fern’s not just a product. It’s the backbone of modern API companies.
You don’t build momentum like this by accident. You build it by solving real problems, shipping relentlessly, and knowing your users better than they know themselves.
Stay tuned. The future of developer infrastructure is about to get a whole lot more automatic.