2025-10-01 –, OSPO, governance and business
Mockoon is one of the most popular open-source API tools, built and maintained from Luxembourg. In this talk, its creator shares the journey of growing a developer tool used by thousands, without external funding. Learn what worked (and didn't) in the pursuit of sustainability through sponsorships, community, and a cloud SaaS offering.
Building and maintaining a successful open-source project is hard, sustaining it is even harder. Mockoon, an open-source API mocking tool created in 2017, has grown to tens of thousands of users around the world, including teams in Fortune 500 companies. But behind the scenes, like many OSS maintainers, its creator faced a familiar challenge: how to keep the lights on without VC funding or a big company backing.
This talk will walk through Mockoon's path to financial sustainability: bootstrapping with freelance work, launching a complementary paid cloud product, building a GitHub Sponsors strategy, and engaging with a global developer audience, all while staying independent. We'll discuss the balance between open-source values and monetization, what helped grow and retain users, and share honest lessons learned from 8 years of OSS maintenance. Ideal for developers, maintainers, and anyone exploring open-source sustainability models.
Guillaume Monnet is the creator and maintainer of Mockoon, one of the most widely used open-source API mocking tools (1 million downloads, 7k GitHub stars, selected by GitHub Accelerator). A full-stack developer based in Luxembourg, Guillaume has over a decade of experience working with startups and building developer tools. He currently bootstraps Mockoon full-time, combining open-source development with a sustainable cloud offering, while occasionally advising startups as a freelance technical consultant and fractional CTO.