Congratulations to the recipients of the 2025 Spotify FOSS Fund | Spotify Engineering (opens in new tab)
Spotify’s 2025 FOSS Fund provided €30,000 to FFmpeg, €15,000 to Mock Service Worker (MSW), and support to the Xiph.Org Foundation. The grants recognize both large, foundational projects and smaller efforts maintained by individuals, emphasizing that Spotify’s technology depends on volunteer-driven open source. Maintainers describe the funds as valuable for development, infrastructure, contributor support, and long-term sustainability. ## Spotify’s FOSS Fund - Established in 2022 to support open source projects that Spotify relies on and its developers value. - The 2025 recipients were: - FFmpeg - Mock Service Worker (MSW) - Xiph.Org Foundation - FFmpeg and Xiph.Org support technologies fundamental to streaming, while MSW is primarily maintained by its creator. - Despite differences in scale, all three projects depend heavily on volunteer contributions. ## FFmpeg: €30,000 - FFmpeg has been actively developed for more than 25 years and supports: - Multimedia encoding and decoding - Transcoding - Muxing and demuxing - Filtering - Streaming and playback - Its goal is to play every multimedia file ever created, making it widely used by hobbyists and companies such as YouTube, Netflix, X, and Spotify. - Maintainer Kieran Kunhya said the project is written almost entirely by volunteers. - The funding will support: - Hardware purchases - Conference travel - Development projects - FFmpeg’s maintainers argue that company donations also raise awareness of the project’s importance and demonstrate responsibility toward critical dependencies. - They identify reliable, long-term funding and dedicated company developers as major unmet needs in open source sustainability. ## Mock Service Worker: €15,000 - MSW is a JavaScript library for API mocking used by Spotify for unit testing and across its web stack. - Creator Artem Zakharchenko is the project’s sole full-time maintainer, supported by a small group of active contributors. - Major 2025 improvements included: - A new Interceptors architecture - Custom mock agents operating at the Node.js `node:net` level - First-class Server-Sent Events support - Planned work for 2026 includes: - A redesigned internal architecture - A new approach to request interception - Remote request interception, a technically difficult feature under development for several years - The previous Spotify grant primarily helped Artem support himself while working full time on open source. - The new funding will directly support continued MSW development and efforts to make external contributions more financially sustainable. - Artem notes that many contributors have been reluctant to accept payment, creating an ongoing challenge in building a sustainable maintainer and contributor community. ## Xiph.Org Foundation - The post identifies the Xiph.Org Foundation as a 2025 recipient and groups it with FFmpeg as a project representing technology fundamental to streaming. - The provided text does not include further details about the foundation’s grant amount, projects, or maintainer comments. Spotify’s grants illustrate how companies can support both major infrastructure projects and individual maintainers. Recurring funding, paid development time, contributor compensation, and practical resources such as hardware and conference travel remain important to the long-term health of open source.