Stackblitz

StackBlitz was founded in 2017 by childhood friends Eric Simons (CEO) and Albert Pai (CTO), who had previously co-founded Thinkster, an online programming-education startup (Simons famously squatted at AOL's headquarters at age 19 while building it). Frustrated by how unreliable and painful local development-environment setup was for teaching people to code, the pair spent roughly three years building WebContainers, a WebAssembly-based micro operating system that lets a full Node.js development environment boot and run entirely inside a browser tab in milliseconds, with no server-side compute. StackBlitz's flagship product became a collaborative, VS Code-based browser IDE built on this technology, used for prototyping, debugging, and interactive tutorials by engineering teams at companies including Google, Cloudflare, Uber, and Shopify, and it grew to roughly 2 million developers per month by 2022. The company raised its first disclosed institutional capital in April 2022: a $7.9 million seed round led by Greylock, with participation from GV (Google Ventures) and angel investors including GitHub co-founder Tom Preston-Werner, atSpoke co-founder Jay Srinivasan, and Appurify co-founder Pratyus Patnaik.

Despite strong developer adoption, StackBlitz struggled for years to convert its technology into a large, monetizable business. By late 2023 the company was, in Business Insider's words, 'the startup equivalent of the walking dead' -- revenue was thin, growth was lackluster, and at a December 2023 board meeting, board members including Insight Partners' Thomas Krane and investor/board director Sarah Guo told Simons and Pai that 2024 would be a make-or-break year, with the board discussing acquisition scenarios as a fallback. A previously unreported $22 million Series A round (disclosed only retroactively by Sacra's research in December 2025) had been raised at some point in this stretch. In early 2024 the founders briefly experimented with OpenAI models for code generation but found the output too unreliable and shelved the idea. The turning point came in June 2024, when Anthropic released Claude 3.5 Sonnet, a dramatically more capable coding model. StackBlitz spent that summer building a new product, and on October 3, 2024, launched Bolt.new -- a simple text box, powered by Claude and StackBlitz's existing WebContainers infrastructure, that let anyone describe a web app in plain English and have Bolt generate, run, and let them edit a working full-stack application entirely in the browser.

Bolt.new's growth was explosive: it generated roughly $1 million in ARR in its first week alone, reached $4 million ARR within 30 days (active customers grew from about 600 to over 14,000), hit $20 million ARR by early December 2024 (per Simons' appearance on the No Priors podcast), and reached $40 million ARR by mid-March 2025. StackBlitz introduced usage-tiered pricing (raising its base plan from $9 to $20/month and adding $50/$100/$200 tiers) after discovering customers were willing to pay heavily for more AI token consumption. The company added Supabase for backend/data services and Stripe for payments, and structured a (ultimately unsigned) $300,000 uncapped WebContainers licensing deal with Anthropic that lapsed in October 2024 just as Bolt was taking off. In January 2025, StackBlitz raised a $105.5 million Series B co-led by Emergence Capital and GV, with participation from Madrona Venture Group, Conviction (Sarah Guo's firm), and Mantis (The Chainsmokers' venture fund), valuing the company at roughly $700 million and bringing disclosed total funding to $105 million at the time (later reported as $135 million in total across all rounds by Sacra in December 2025). Other investors named across StackBlitz's cap table include Greylock, Insight Partners, Flex Capital, and Tribe Capital.

Business model

Freemium/PLG browser-based IDE (StackBlitz core product) plus a token-based subscription AI app-builder (Bolt.new), supplemented by Enterprise Server on-prem/behind-firewall licensing, a WebContainer API licensing business (e.g., to Anthropic), and enterprise marketplace procurement (AWS Marketplace, Microsoft Marketplace) for Bolt.

Bolt.new: tiered, token-consumption-based subscriptions (Free, Pro ~$25/mo with 10M tokens, Teams ~$30/user/mo, Enterprise custom, incl. $100K base AWS Marketplace 12-month contracts plus per-seat and per-token fees). StackBlitz core: freemium with paid tiers from $9-20/mo for private projects, Enterprise Server licensing/support contracts, and WebContainers API/technology licensing to third parties.