You asked about Open Source
30 people built something like it. 1 is gone.
That is 3% of the ones whose fate we could settle, against 23% across the whole register. 1 were acquired.
| Launched | What it was | Today |
|---|---|---|
| 2025-01-01 | YCMastra The Javascript framework for building AI agents, from the Gatsby devs · mastra.ai | still up |
| 2025-06-01 | YCKERNEL Crazy fast, open source infra for AI agents to use the Internet · kernel.sh | still up |
| 2025-01-01 | YCMentra Building the open source smart glasses operating system. · mentra.glass | still up |
| 2025-06-01 | Tiny Edge AI For Tiny Devices · cactuscompute.com | still up |
| 2025-01-01 | The LLM Eval and Observability Platform for AI Quality · confident-ai.com | still up |
| 2025-01-01 | Agents that use the browser. · browser-use.com | still up |
| 2025-01-01 | connect, migrate and implement enterprise systems · superglue.ai | still up |
| 2025-06-01 | YCManufact Cloud infrastructure for MCP servers and Claude / ChatGPT plugins. · manufact.com | still up |
| 2025-09-01 | Simulate your customers with AI agents · expectedparrot.com | still up |
| 2025-09-01 | YCs2.dev API for unlimited, durable, real-time streams · s2.dev | still up |
| 2025-06-01 | YCOmnara The Open-Source Alternative to Claude Managed Agents · omnara.com | still up |
| 2025-09-01 | Helping humans and AI agents understand massive codebases · sourcebot.dev | still up |
| 2025-06-01 | YCPangolin Open networking and security for your workforce, AI agents, and infra · pangolin.net | still up |
| 2025-01-01 | Open Source React.js Library for AI Chat · assistant-ui.com | still up |
| 2025-06-01 | Open source self-improving layer for AI agents · traceroot.ai | still up |
| 2025-01-01 | YCCorsair OpenRouter for Integrations · corsair.dev | still up |
| 2025-06-01 | YCChar The AI notepad that knows and works for you · char.com | still up |
| 2025-06-01 | The Open Source Agentic IDE · stagewise.io | still up |
| 2025-06-01 | Open source inference server for local models · magnitude.dev | still up |
| 2025-01-01 | The fastest native app for agentic engineering. · teetimetommy.com | still up |
| 2025-01-01 | Daily productivity tracker · sublingual.ai | gone |
| 2025-06-01 | ChatGPT's memory feature in an open, portable format · epicenter.so | still up |
| 2025-01-01 | YCYouShift The OS for hospital workforce management · you-shift.com | still up |
| 2025-09-01 | YCSorce Tinder for jobs · sorce.jobs | still up |
| 2025-09-01 | YCOpenroll The AI workforce for People and Finance teams · openroll.com | still up |
| 2025-06-01 | YCSira AI Native Rippling for Deskless Workers · sira.team | still up |
| 2025-01-01 | YCSubImage The Open-Core Security Graph · subimage.io | still up |
| 2025-06-01 | YCOpennote The notebook that thinks with you. · opennote.com | acquired |
| 2025-06-01 | World's largest crowdsourced benchmark for AI-generated design · designarena.ai | still up |
| 2025-01-01 | The AI Front Door For Law Firms · openintake.ai | still up |
How this compares
The register re-probes every domain it holds. Some that answered last month stop answering. We send that list — what went quiet, and what it was — once a month. Nothing else.
How this was made. Show HN entries are every post from 2021 to 2023 with at least five points that linked to its own domain; code hosts and free hosting are excluded, because a repository outlives the effort behind it. Product Hunt entries needed 100 votes — a far higher bar, so they are the promoted top slice rather than a like-for-like sample. Both are judged by asking the domain whether it still answers: gone means it no longer resolves, refuses the connection, serves a parking page, or says plainly that it shut down. An HTTP error is not counted as gone — a server answering 404 is one somebody still pays for, and an audit of 25 gone-calls found two such sites alive with only a moved homepage. Y Combinator entries use the status YC publishes itself, which is why only those can say acquired. Squatted domains — a lapsed name now serving somebody else's site — are not detected, so these figures run slightly low.