startup ideas · graveyard
Dead startup ideas worth reviving
Of the 14,761 accelerator companies from 2018 onwards that MarkosWeb can check, 2,013 (14%) are dead: Y Combinator marks them inactive, or their website no longer answers. A dead company is not a dead idea. The list below sorts graveyards by how many new companies entered the same cluster in 2025-26 and are still alive - the clearest sign that founders believe the timing has changed.
2,013
dead or vanished since 2018
14%
of checked companies
63
YC shutdowns since 2026-02
15
clusters with a graveyard
How to tell a revivable idea from a dead one
- The blocker flipped. Most of these companies were right about the destination and early on a dependency: model cost, a regulation, a distribution channel, hardware price. Check which one killed the original and whether it has moved since.
- Someone still pays. A real buyer has to be paying for a worse solution today. Run the one-liner through Idea Check to see who is alive in the same space and how alive they are.
- Founders are coming back. The re-entrant count next to each cluster is the number of 2025-26 companies building there now. A graveyard nobody re-enters is a warning; one with hundreds of new entrants is a market that was early, not wrong.
Graveyards founders are re-entering
Per cluster: companies dead since 2018 with a recorded one-liner, the number of live 2025-26 entrants, and the most recent casualties. Names link to their MarkosWeb domain report.
Vertical AI agents96 dead · 568 new entrants since 2025
- Cofactory · Plug and Play PnP 2026 · 2026 - Cofactory turns websites into autonomous AI sales agents that generate personalized landing pages and ads, continuously optimizing conversions based on real-time buyer intent.
- Q2Q · Y Combinator W26 · 2026 - We help private equity teams find acquisition targets faster
- August · a16z speedrun SR006 · 2026 - AI autonomous bankers
- Remedy · Y Combinator F25 · 2025 - AI Agents for Pharmacies
- Loan Labs · a16z speedrun SR005 · 2025 - We're building agentic workers for mortgage companies. We liberate humans from having to do soul-crushing work. When we liberate the humans, the industry will prosper.
- Oblix, Inc · 500 Global · 2025 - Helping pentesters do 10x more security testing with autonomous offensive AI agents
Agent infrastructure25 dead · 244 new entrants since 2025
- Nodus Compute · Y Combinator F26 · 2026 - Intelligent execution layer for AI workloads
- Grumatic · Plug and Play PnP 2026 · 2026 - Grumatic is an AI intelligence platform that measures prompt quality, detects cost waste, and optimizes developer productivity for AI coding agents (Claude Code, Codex CLI and so on).
- Sylvian · Y Combinator F25 · 2025 - Specialized AI Agents.
- Nuntius · Y Combinator S25 · 2025 - Making Models Follow Rules.
- Propolis · Y Combinator X25 · 2025 - Hands off QA via intelligent browser agents.
- Satellica · antler Antler Canada 2025 · 2025 - AI Infrastructure for Customer-Driven Decisions
Robotics and physical world82 dead · 208 new entrants since 2025
- WembraneX · Plug and Play PnP 2026 · 2026 - Wembranex produces a Polymeric membrane applied to filtration systems in industrial processes able to reduce "fouling" generated by water separation.
- Trailslight · Plug and Play PnP 2026 · 2026 - Trailslight has developed an AI-driven sound-based traffic recognition systems integrated into public lighting infrastructure.
- Canovation · Plug and Play PnP 2026 · 2026 - Canovation is revolutionizing the CPG packaging industry with CanReseal®, an all-metal, fully resealable can that is compatible with existing manufacturing and supply chains, offering brands and consumers an all-in-one sustainable packaging solution.
- JYC Inc. · Plug and Play PnP 2026 · 2026 - JYC Inc. develops an AI-powered food safety inspection solution using SWIR imaging and hyperspectral analysis. Their system detects invisible contamination such as bacteria, foreign materials, and spoilage in real-time without physical contact, enabling rapid and scalable food safety management ...
- Spacedrip · Plug and Play PnP 2026 · 2026 - Reuse 95% of wastewater while spending less and saving the planet
- Kyten Technologies · Y Combinator W26 · 2026 - Custom Aerospace-Grade Battery Packs
Healthcare and bio104 dead · 206 new entrants since 2025
- NEXI Biotech Inc · Plug and Play PnP 2026 · 2026 - NEXI Biotech develops in vitro neurotechnology models for improved neurological drug discovery and translation.
- WearableDose · Plug and Play PnP 2026 · 2026 - WearableDose improves radiotherapy using an innovative electronic polymer detector that accurately detects, directs, and measures radiation to tumors, reducing costs and significantly enhancing treatment safety and efficacy.
- OsseoLabs · Plug and Play PnP 2025 · 2025 - OsseoLabs pioneers AI-driven surgical planning and 3D-printed metal and bioresorbable implants to improve patient outcomes, reduce surgical risks, and bring precision care to hospitals globally.
- Intelligent Implants · Plug and Play PnP 2025 · 2025 - Intelligent Implants integrates electronics into standard orthopedic instrumentation getting bone to grow faster, preventing non-unions
- Layers · Y Combinator F25 · 2025 - A 30 min appointment to measure everything in your body
- Bioeureka · Plug and Play PnP 2025 · 2025 - AI-powered image recognition technology for rapid pathogen identification.
Fintech156 dead · 167 new entrants since 2025
- Finalytics.ai · Plug and Play PnP 2026 · 2026 - Finalytics.ai enables financial institutions to instantly unleash the power of AI by offering segment of one digital experiences for visitors informed by behavioral, transactional, and 3rd party data.
- Scenariox · 500 Global · 2025 - An AI and quantum platform empowering financial institutions to make faster, and more insightful risk decisions where traditional models fall short.
- Collecto · antler Antler India 2025 · 2025 - Empowering SMBs by Solving Cash Flow and Payment Collection Challenges
- RiFD · antler Antler Saudi Arabia 2025 · 2025 - Transforming supply chain receivables into accessible capital through data-driven securitization.
- Excarta · Plug and Play PnP 2024 · 2024 - Excarta uses AI to reduce insurance losses caused by catastrophic weather.
- Flap Insurance · Plug and Play PnP 2024 · 2024 - Building an AI-powered distribution platform for insurance companies.
Consumer241 dead · 154 new entrants since 2025
- Cravv · antler Antler 2026 · 2026 - An AI-powered kitchen assistant that combines real-time safety monitoring with intelligent cooking guidance to protect families at the stove.
- dinefind.ca · Plug and Play PnP 2025 · 2025 - Discover Restaurant Options For Allergies & Special Diets
- First Voyage · a16z speedrun SR005 · 2025 - Modern mythologies to help people live healthier, happier lives.
- Lumin Fitness · Plug and Play PnP 2025 · 2025 - Lumin Fitness is the future of workouts—where smart technology, immersive environments, and personalized coaching come together to create a fitness experience that’s interactive, effective, and designed for you.
- Tee Time Tommy · Y Combinator W25 · 2025 - Book and manage all of your golf tee times in one place.
- Edgar · a16z speedrun SR004 · 2025 - Bringing real money engagement into F2P via sweepstakes
B2B SaaS184 dead · 141 new entrants since 2025
- 株式会社Chai · Plug and Play PnP 2026 · 2026 - 500万人のAIペルソナへの仮説検証で市場ニーズを短時間取得するAIリサーチサービスを提供
- Smartbase · Y Combinator X26 · 2026 - AI-native ERP for manufacturers
- Anchorhead · Y Combinator W26 · 2026 - Evals for frontier research agents
- Providential Media · Plug and Play PnP 2025 · 2025 - Innovation to WIN the New Era of Fan Engagement
- Checkmate · a16z speedrun SR004 · 2025 - Building AI-native Vertical SaaS
- Clipflow · antler Antler Australia 2025 · 2025 - Project Management for Content Creators
Developer tools117 dead · 111 new entrants since 2025
- EverySim · 500 Global · 2025 - Developer of a cloud-native engineering simulation platform designed to enable browser-based design, testing, and optimization of UAV airframes. The company integrates CFD, FEA, and AI-driven optimization into a single SaaS workflow that replaces fragmented toolchains and costly hardware, enabling both expert and non-expert engineers to run high-fidelity simulations easily and affordably.
- Rovr · Y Combinator F25 · 2025 - AI FDE Engine that runs your engineering workflows
- Sublingual · Y Combinator W25 · 2025 - Daily productivity tracker
- Audiomatic · antler Antler United Arab Emirates 2025 · 2025 - AI-powered sound generation engine that creates bespoke audio tracks (music & sound effects) for immersive experiences like games and movies.
- Paracosmic · ef EF London 2025 · 2025 - Sentence-to-world game creation for studios.
- Holo-Light · Plug and Play PnP 2024 · 2024 - Holo-Light is a software development company providing technology, which enables the efficient usage of Augmented Reality in industrial environments.
7 more clusters
Climate and energy67 dead · 98 new entrants since 2025
- 4th State Energies · Plug and Play PnP 2026 · 2026 - 4th State Energies develops plasma-created silicon anode material to revolutionize lithium-ion batteries with significantly higher energy density and lower production costs, making them a drop-in replacement for graphite.
- Evoxia Labs · Plug and Play PnP 2026 · 2026 - Bioplastics to substitute fossil plastics.
- Membravo, Inc. · Plug and Play PnP 2025 · 2025 - Hydrogen separation membranes for lower cost, lower carbon hydrogen
- ZENCE OBJECT TECH · Plug and Play PnP 2025 · 2025 - Zence Object is an all-in-one sustainable partner, offering personalised waste to treasures material solutions.
AI infra and compute16 dead · 96 new entrants since 2025
- Calejo · Plug and Play PnP 2026 · 2026 - Calejo is an intelligence platforms that leverages the AI-potential helping corporates to optimize their business.
- Zant · Plug and Play PnP 2026 · 2026 - Zant simplifies and accelerates the deployment of AI models on edge devices, where cloud-based execution is limited by privacy, latency, or connectivity constraints.
- deepsilicon · Y Combinator S24 · 2024 - Software and hardware to run neural networks faster and cheaper
- Blyss · Y Combinator W23 · 2023 - End-to-end encrypted AI.
Data for AI39 dead · 82 new entrants since 2025
- Praxis Robotics · Y Combinator S26 · 2026 - Turns real businesses into robotics data vendors
- Sciloop · Y Combinator F25 · 2025 - Expert STEM reasoning data for frontier AI labs.
- Entrii · Plug and Play PnP 2025 · 2025 - Obtain analyzed data from retail and online commerce, with the key indicators for designing your growth strategy in international markets.
- Percival · Y Combinator X25 · 2025 - Accelerating data analysis for research
Security and compliance33 dead · 79 new entrants since 2025
- Cerberus · 500 Global 500G Eurasia 10 · 2026 - Cerberus is the world's first mathematically safe AI ethical hacker — the "Cursor for hacking" that makes security teams 10x more productive with AI that's provably guaranteed never to cause harm.
- Armilla AI · Plug and Play PnP 2025 · 2025 - Armilla AI protects organisations from AI risks.
- Nova · antler Antler United Arab Emirates 2025 · 2025 - AI-native contract intelligence platform enabling users to analyze, generate, and sign contracts
- Veriply · Plug and Play PnP 2024 · 2024 - Veriply is developing real-time internal audit tools for B2B transactions.
Commerce and marketplaces126 dead · 70 new entrants since 2025
- Partner Success · Plug and Play PnP 2026 · 2026 - 代理店連携管理クラウドサービス「PartnerSuccess(パートナーサクセス)」の提供
- Dome · Y Combinator F25 · 2025 - A unified API for prediction markets, like Kalshi and Polymarket
- MVX · Plug and Play PnP 2025 · 2025 - An Austin and Lagos-based software company simplifying global trade for businesses in emerging markets using technology; MVX & TradeAlly.
- Cafler · Plug and Play PnP 2024 · 2024 - Cafler is the leading marketplace for car services online, and an AI- Operating System for mobility companies.
Horizontal AI assistants43 dead · 69 new entrants since 2025
- BaseFrame · Y Combinator W26 · 2026 - Detect what AI can automate for your team
- DealLoop · spc · 2025 - Real-time intelligence for live conversations
- AQ22 · Plug and Play PnP 2024 · 2024 - AQ22 is a loan assessment AI solution built exclusively for credit analysts. Our platform boosts loan assessment efficiency, accuracy, and transparency for creditors, credit unions, and alternative lenders.
- supercontrast · Y Combinator F24 · 2024 - AI Co-Pilot for Design
Defense and space8 dead · 65 new entrants since 2025
- Spacedock (fma Orbital Outpost X) · Plug and Play PnP 2025 · 2025 - Spacedock is developing the intelligent plug and play connector for scaling space infrastructure.
- Spaceverse · Plug and Play PnP 2024 · 2024 - The Algorithm of Emotions
- Outbound Aerospace · antler Antler US 2024 · 2024 - Designing and building next generation airplanes.
- HStar · antler Antler US 2022 · 2022 - HStar building rapidly and fully reusable heavy rockets and spaceship to provide launch services around the world.
Shut down in the last six months
YC companies that were active in the 2026-02 snapshot and are marked inactive today (63). The freshest graveyard: the reason each one closed is still findable, and the buyers are still out there. Full trajectory report.
- Kyten Technologies · W26 · Robotics and physical world - Custom Aerospace-Grade Battery Packs
- Mendral · W26 · Vertical AI agents - AI DevOps Engineer
- Dome · F25 · Commerce and marketplaces - A unified API for prediction markets, like Kalshi and Polymarket
- Rovr · F25 · Developer tools - AI FDE Engine that runs your engineering workflows
- Percival · X25 · Data for AI - Accelerating data analysis for research
- Altrina · W25 · Vertical AI agents - The SOP Automation Platform
- Baseline AI · S24 · Vertical AI agents - AI document creation and data management for clinical trials
- camfer · S24 · Developer tools - Building the world’s first AI mechanical engineer.
- Lilac Labs · S24 · Vertical AI agents - We automate the person taking orders at drive-thrus with a voice AI
- Pre · S24 · Horizontal AI assistants - The AI accountability agent for startup founders
- Aedilic · W24 · Security and compliance - Open-Source AI-generated image/deepfake detection
- Glimmer · W24 · Data for AI - AI search for massive PDFs
- K-Scale Labs · W24 · Robotics and physical world - Open-source humanoid robots
- Preloop · W24 · Developer tools - Translate your experimental scripts into production ML services
- Tesseral · W24 · Agent infrastructure - The open source platform for managing identity in business software
- Thorntale · W24 · Horizontal AI assistants - The world's best presentation editor, powered by AI.
- Atla · S23 · Agent infrastructure - The improvement engine for AI agents
- Leafpress · S23 · Climate and energy - AI Energy Management
- Synch · S23 · B2B SaaS - Supercharging Sales
- Fetchr · W23 · Consumer - The Personal Shopper in Your Pocket
- Gluetrail · W23 · Developer tools - Create step by step articles with screenshots and videos 10x faster
- Homeflow · W23 · B2B SaaS - Simplifying insurance for large real estate investors
- Peeba · W23 · Commerce and marketplaces - Risk-free wholesale for retailers across Southeast Asia
- rift · W23 · B2B SaaS - B2B lead routing made simple
- Turntable · W23 · Developer tools - AI-native operating system for analytics teams
- Almond · S22 · Healthcare and bio - We make it easy to get great ObGyn care in-person and over telehealth
- Alima · W22 · Commerce and marketplaces - Fresh procurement made easy
- Livedocs · W22 · B2B SaaS - A New Kind of Notebook for Data Storytelling
- ngrow.ai · W22 · B2B SaaS - Low-code SaaS for marketing in push notifications
- PeakPath · W22 · B2B SaaS - Smartwatch powered coaching to improve teams sustainable performance
- Ploomber · W22 · AI infra and compute - Heroku for AI
- Seis · W22 · Fintech - Banking 100% in Spanish for the 44 million US Spanish speakers
- Uberduck · W22 · Horizontal AI assistants - Fast, professional content creation with AI audio, image, and video.
- Heimdal · S21 · Climate and energy - Affordable and verified direct air carbon capture and storage
- Mine · S21 · Consumer - The AI personal finance company.
- Nino Foods · S21 · Consumer - Building India's fast food empire
- OneStopKitchen · S21 · Vertical AI agents - AI-Driven Tech & Space Optimization to Scale Restaurants
- outloud.ai · S21 · Vertical AI agents - Building Gong.io for offline retail.
- Patterns · S21 · Vertical AI agents - Next-Gen Financial Analysis and Reporting with AI Agents
- PAYZE · S21 · Fintech - Stripe for former Soviet Union countries
- PropReturns · S21 · Commerce and marketplaces - End-to-end commercial real estate transaction platform
- TAG · S21 · Fintech - TAG is the First Digital Bank (Chime/Revolut/N26) for Pakistan
- Verde · S21 · Fintech - Digital lending platform for Brazilian farmers
- AXAR AI · W21 · Developer tools - Multi-agent orchestration platform
- ControlHub · W21 · Commerce and marketplaces - Purchasing Software | Procure-to-Pay SaaS
- Faction · W21 · Robotics and physical world - Driverless electric vehicles at a fraction of the cost of a car.
- Forcyte Biotechnologies · W21 · Healthcare and bio - Discover drugs that control how much cells "squeeze" to treat disease
- Lovd · W21 · Consumer - It's not used, it's Lovd.
- MindPortal · W21 · AI infra and compute - Thought-to-Language AI Models
- Payflow · S20 · Vertical AI agents - AI FP&A Agent for insights, reports, planning and forecasting.
- Shuttle · S20 · Developer tools - Build Backends. Fast.
- Breathe Well-being · W20 · Healthcare and bio - A digital well-being program to help people prevent or manage chronic…
- Peg (formerly Paymobil) · W20 · Fintech - The super simple stablecoin wallet with free transactions
- AudioFocus · S19 · Healthcare and bio - Hearing aids that work in noisy places, like restaurants, using ML.
- PlayAbly · S19 · B2B SaaS - We build games to help brands engage, convert, and retain customers
- Bensen · W19 · Commerce and marketplaces - Online and phone ordering for restaurant takeout and delivery
- Endpoint Health · W19 · Healthcare and bio - Precision-first therapies
- Parker · W19 · Fintech - Parker is a digital bank.
- Federacy · S18 · Security and compliance - Penetration testing and bug bounty platform.
- Torch · W18 · B2B SaaS - Leadership Development & Coaching Solutions | Torch
- NuCypher (aka Threshold Network) · S16 · Agent infrastructure - Network for decentralized threshold cryptography and end-to-end…
- Scope AR · S15 · B2B SaaS - Scope AR is the leading provider of User Guided Augmented Reality…
- Billforward · S14 · Fintech - Subscription billing, rate plan management and analytics as a…
More startup ideas by angle
- AI startup ideas →Where AI-native companies are actually being built
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- Stealth startups →How many accelerator startups are really in stealth
Validate any of them: Idea Check shows who already builds it; Idea Lab writes concepts from a cluster's data; Chat matches ideas to what you can build.