In June 2023, Anton Osika was CTO at Depict.ai when he built GPT-Engineer as a weekend side project — an open-source tool that could generate entire codebases from a single prompt. He shared it on Twitter and it became the fastest-growing GitHub repository ever, hitting 52,000 stars.

The Open Source Flywheel

That viral moment built something more valuable than downloads: a 27,000-person waitlist of developers who wanted a commercial version. Anton and Fabian Hedin (26 years old, who'd previously worked on Stephen Hawking's communication interface) co-founded the company in Stockholm in November 2023.

Two Failed Launches

The commercial gptengineer.app launched in August 2024 to modest results. Growth flatlined. They tried again. Failed again. In the founder's own words, the product "flopped twice." Most teams would have pivoted away. Anton and Fabian did something different — they rebranded to "Lovable" and completely repositioned the product around vibe-coding: building apps by describing what you want in plain English.

The Rebrand That Changed Everything

On November 21, 2024, Lovable launched and hit #1 on Product Hunt and Hacker News simultaneously. The 27,000-person waitlist from the open-source era flooded in. Within 4 weeks they hit $4M ARR. By day 60: $10M ARR with just 15 people. By month 8: $100M ARR.

• Open source: 52,000 GitHub stars (fastest-growing repo ever)
• Waitlist: 27,000 people before commercial launch
• $4M ARR: 4 weeks
• $10M ARR: 60 days (with 15 people)
• $100M ARR: ~8 months
• Series A: $200M at $1.8B valuation (July 2025)
• 85% Day-30 retention (higher than ChatGPT)