You asked about Reinforcement Learning
63 people built something like it. 14 are gone.
That is 25% of the ones whose fate we could settle, against 23% across the whole register. 7 were acquired.
| Launched | What it was | Today |
|---|---|---|
| 2021-01-01 | Live online courses that turn learners into builders · coderhouse.com | still up |
| 2021-01-01 | YCKiwify Create & sell online courses · kiwify.com.br | still up |
| 2021-06-01 | YCNovatr Online cohort based courses for architects, engineers and designers… · novatr.com | still up |
| 2021-01-01 | The online language school for Latam, with groups led by an instructor · poliglota.org | still up |
| 2021-06-01 | YCBaubap Smart micro financing for everyone · baubap.com | still up |
| 2021-01-01 | YCEncord The data layer for physical AI · encord.com | still up |
| 2021-06-01 | YClapzo Lattice for Latam with personalized learning and development · lapzo.com | still up |
| 2021-06-01 | YCFiladd We help students in Latin America graduate from College. · filadd.com | still up |
| 2021-06-01 | Learning platform for job seekers with job applications automation · careerist.cc | still up |
| 2021-06-01 | YCStepful Online Training for Healthcare Jobs · stepful.com | still up |
| 2021-01-01 | YCCodingal Leading online after-school for kids & teens to learn AI & coding · codingal.com | still up |
| 2021-01-01 | YCMindee AI Document Understanding API · mindee.com | still up |
| 2021-01-01 | YCSoraban AI tax workflow platform for accounting firms · soraban.com | still up |
| 2021-06-01 | Building Job driven Virtual Tech University for India 🇮🇳 · algouniversity.com | still up |
| 2021-01-01 | YCAwari Reinventing lifelong learning for the future of work. · awari.com | acquired |
| 2021-01-01 | YCUnschool Learn, Intern and become Industry-Ready · unschool.in | still up |
| 2021-06-01 | YCPandai Learning app for school students in Southeast Asia · pandai.org | still up |
| 2021-06-01 | The most magical personal Voice-Led AI English Learning Buddy for Kids · sparkstudio.co | still up |
| 2021-06-01 | A national network of microschools bringing school choice to every… · kaipodlearning.com | still up |
| 2021-06-01 | YCMach9 AI CAD Software for Civil Engineering · mach9.ai | still up |
| 2021-06-01 | YCMindFi Transforming Mental Health for Corporate Asia · mindfi.co | still up |
| 2021-06-01 | The fastest way to ship airtight AI · openlayer.com | still up |
| 2021-06-01 | Water risk mitigation for industrial sites · waterplan.com | still up |
| 2021-01-01 | A skill-tech platform that runs placement bootcamps · functionup.org | acquired |
| 2021-06-01 | The world's largest financial education and community app for women · femaleinvest.com | still up |
| 2021-01-01 | YCAnima The next generation care enablement platform · animahealth.com | still up |
| 2021-06-01 | YCAkudo India's first learning-focused neobank for teenagers · akudo.in | gone |
| 2021-01-01 | YCSpokn AI-powered video platform for Internal Comms and HR teams · getspokn.com | still up |
| 2021-01-01 | Embed NL-to-SQL into your Product 📈 · dataherald.com | gone |
| 2021-06-01 | YCSlope The B2B Payments Platform · slopepay.com | still up |
| 2021-01-01 | YCKidato Online school for K12 education in Africa · kidato.com | still up |
| 2021-01-01 | YCInvoid Create identity verification workflows the way you want · invoid.co | gone |
| 2021-01-01 | Dramatically better search and ads for marketplaces · promoted.ai | acquired |
| 2021-01-01 | YCMystic Low latency API to run and deploy ML models · mystic.ai | gone |
| 2021-01-01 | Procure the right software 5x faster · expent.ai | still up |
| 2021-06-01 | YCCero Automated communication between hospitals and patients in Latam · cero.ai | still up |
| 2021-06-01 | YCKurios Cohort-based online courses for professionals in Latin America · kurios.la | gone |
| 2021-06-01 | Plan and review AI generated code · vibekanban.com | still up |
| 2021-01-01 | YCPipeBio PipeBio is a SaaS bioinformatics platform to develop antibody drugs. · pipebio.com | acquired |
| 2021-06-01 | YCSafeBeat First ECG AI to go beyond diagnostics and recommend treatment · safebeat.com | still up |
| 2021-01-01 | Build better computer vision models by building better datasets · segments.ai | acquired |
| 2021-01-01 | YCBiodock Cloud AI microscopy automation · biodock.ai | still up |
| 2021-06-01 | YCSpoken Never overpay online · spoken.io | gone |
| 2021-06-01 | Automating procurement and finance for construction companies · concordmaterials.com | still up |
| 2021-06-01 | AI-designed Affinity Reagents · medium.bio | still up |
| 2021-06-01 | YCSleek Browser automation for businesses. · onsleek.com | acquired |
| 2021-01-01 | YCSimplify Helping a billion people build their dream career · simplify.jobs | still up |
| 2021-06-01 | YCLightly Help ML teams label the right data · lightly.ai | still up |
| 2021-06-01 | Building Gong.io for offline retail. · outloud.ai | gone |
| 2021-06-01 | Computer vision that makes the industrial workplace, safer · protex.ai | still up |
| 2021-01-01 | YCPrendea Live afterschool classes for Spanish-speaking kids ages 4 to 15. · prendea.com | gone |
| 2021-01-01 | Business intelligence on text · hyperglue.com | acquired |
| 2021-01-01 | Synthetic data for better vision. · sbxrobotics.com | gone |
| 2021-06-01 | Student Attendance tracking for Public Schools · safermgmt.com | still up |
| 2021-06-01 | The dynamic single-cell analysis company · cellchorus.com | still up |
| 2021-01-01 | We teach Filipinos to become remote software engineers globally. · avionschool.com | gone |
| 2021-01-01 | Breaking new ground in online eyecare. · quadranteye.com | gone |
| 2021-06-01 | YCBuzzle Automatic voice-of-customer trends & metrics from sales conversations. · buzzle.ai | gone |
| 2021-06-01 | Observability for Data Engineering Teams · lariatdata.com | gone |
| 2021-06-01 | YCSentiyen Conversational AI assistants using your knowledge · sentiyen.com | 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.