Top trending open-source startups in Q3 2025

Snapshot of ROSS Index featuring top open-source startups by GitHub stars growth of their repositories. All descriptions are based on public data and were current as of the end of Q3 2025
  1. OpenCut (OpenCut-app/OpenCut, 32.0K stars, 32.0x growth) is a cross-platform video editor. Founded in 2025.
  2. 🇺🇸 SST (sst/opencode, 22.1K stars, 22.1x growth) built full-stack deployment framework. Now developing OpenCode, a terminal-based AI coding agent. Founded in 2017 in San Francisco. Raised $1.62M from Y Combinator, SV Angel, Greylock, etc.
  3. 🇺🇸 Upstash (upstash/context7, 20.9K stars, 20.9x growth) built serverless data platform. Now developing Context7, an MCP server with up-to-date code documentation AI agents. Founded in 2021 in San Jose, CA. Raised $11.9M from Bek, AngelList, Prototype, ScaleX, Andreessen Horowitz, Mango, etc.
  4. 🇺🇸 Hamster (eyaltoledano/claude-task-master, 17.4K stars, 17.4x growth) builds TaskMaster AI that transforms specs into AI-compatible tasks that integrate directly into your AI dev tools. Founded in 2025 in San Francisco.
  5. 🇺🇸 Winfunc (winfunc/opcode, 16.6K stars, 16.6x growth) builds Asterisk, a codebase vulnerability automation system, and Opcode, a cross-platform client for Claude Code. Founded in 2024 in San Francisco. Raised an undisclosed amount from Multimodal, Orange Collective, Pioneer, Y Combinator.
  6. 🇺🇸 Dyad (dyad-sh/dyad, 14.1K stars, 14.0x growth) is an AI app builder that lets you craft full-stack interfaces from your machine. Founded in 2025 in San Jose, CA.
  7. 🇰🇷 Nari Labs (nari-labs/dia, 17.5K stars, 12.0x growth) develops advanced TTS models capable of generating ultra-realistic, expressive speech from text. Founded in 2025 in Seoul.
  8. 🇺🇸 Astral (astral-sh/ty, 11.2K stars, 11.2x growth) builds high-performance Python tools, including ty, an extremely fast type checker. Founded in 2022 in Brooklyn, NY. Raised $4M from Accel, Base Case Capital, Caffeinated, etc.
  9. 🇨🇦 Resemble AI (resemble-ai/chatterbox, 10.4K stars, 10.4x growth) produces ultra-realistic AI voices and detects deepfake audio in real time. Founded in 2018 in Toronto. Raised $12.2M from Craft, AET, Firstminute, Mercuri, Betaworks, Javelin, etc.
  10. 🇺🇸 Kilo Code (Kilo-Org/kilocode, 9.3K stars, 9.1x growth) is an AI coding assistant. Founded in 2025 in Wilmington, DE.
  11. 🇺🇸 Charm (opencode-ai/opencode, 8.9K stars, 8.9x growth) develops Crush, a terminal-based AI coding agent. Founded in 2019 in New York. Raised $9.9M from Fuel, NAP, Firestreak, Betaworks, Gradient, etc.
  12. 🇺🇸 ASYNCFUNC. (AsyncFuncAI/deepwiki-open, 8.9K stars, 8.9x growth) builds tools like DeepWiki, which auto-generates interactive wikis from codebases. Founded in 2025 in the United States.
  13. 🇨🇳 Krillin AI (krillinai/KrillinAI, 8.0K stars, 8.0x growth) is an AI video translation tool that supports up to 100 languages. Founded in 2024 in China.
  14. 🇺🇸 Kortix (kortix-ai/suna, 16.9K stars, 6.9x growth) is a comprehensive platform for creating autonomous AI agents . Founded in 2024 in San Francisco.
  15. 🇺🇸 Tadata (tadata-org/fastapi_mcp, 6.5K stars, 6.5x growth) helps you build MCP connectors over your APIs, enabling your product to be accessed by AI agents. Founded in 2024 in San Francisco.
  16. 🇩🇪 Stagewise (stagewise-io/stagewise, 5.8K stars, 5.8x growth) is a frontend coding agent. Founded in 2024 in Bielefeld. Raised $0.5M from Y Combinator.
  17. 🇺🇸 CopilotKit (ag-ui-protocol/ag-ui, 5.8K stars, 5.8x growth) develops AG-UI, an event-based Agent-User Interaction protocol. Founded in 2023 in Seattle, WA. Raised $0.12M from Techstars Seattle Accelerator.
  18. 🇺🇸 SurfSense (MODSetter/SurfSense, 5.9K stars, 4.9x growth) is a customizable AI research agent, connected to external data sources. Founded in 2025 in San Jose, CA.
  19. 🇺🇸 Sim (simstudioai/sim, 4.9K stars, 4.9x growth) is a complete platform to build and deploy AI agent workflows. Founded in 2025 in San Francisco. Raised $0.5M from Y Combinator.
  20. 🇨🇳 Funstory.ai (funstory-ai/BabelDOC, 4.5K stars, 4.5x growth) enables AI-powered multilingual publishing, turning local stories into global content. Founded in 2017 in Beijing. Raised an undisclosed amount from NBT Capital, Lianshang Networks, Himalayas, Legend Star, etc.

Anyone with a featuring on ROSS Index Q3 2025 can add the badge to their own website to let site visitors know they are one of the fastest-growing open-source startups.

Visit ROSS Index to see the top-20 open-source startups in other quarters.