You asked about APIs
33 people built something like it. 2 are gone.
That is 9% of the ones whose fate we could settle, against 23% across the whole register. 10 were acquired.
| Launched | What it was | Today |
|---|---|---|
| 2011-06-01 | YCSegment Software and APIs to collect, clean, and control customer data. · segment.com | acquired |
| 2016-01-01 | Protects organizations from getting breached through their APIs. · salt.security | still up |
| 2021-06-01 | YCExa Web search rebuilt for LLMs · exa.ai | still up |
| 2021-01-01 | YCMindee AI Document Understanding API · mindee.com | still up |
| 2015-01-01 | YCMoltin eCommerce building blocks through simple APIs for websites & apps.… · moltin.com | acquired |
| 2024-09-01 | Real-time B2B data via simple APIs · crustdata.com | still up |
| 2022-01-01 | Healthcare Price Transparency APIs and Data Products · serifhealth.com | still up |
| 2024-01-01 | YCMiden Card issuer processor and banking stack for businesses in Sub-… · miden.co | still up |
| 2022-01-01 | YCWingback Wingback provides tools and APIs for SaaS pricing and packaging. · wingback.com | gone |
| 2014-01-01 | YCWit.ai Natural Language for Developers --Wit is an API that makes it easy… · wit.ai | acquired |
| 2014-01-01 | Create APIs where they don't exist. With kimono you can quickly… · kimonolabs.com | acquired |
| 2023-06-01 | YCFiber AI The freshest data APIs for AI sales, recruiting, & growth products · fiber.ai | still up |
| 2018-06-01 | Developer-friendly and enterprise-grade APIs for financial market… · alphavantage.co | still up |
| 2020-01-01 | YCFlowglad Analyze, act, and automate across systems · flowglad.com | still up |
| 2022-01-01 | Customer support tool purpose-built for companies that sell APIs · fogbender.com | still up |
| 2022-01-01 | YCDecent Cross-chain routing + trading APIs. One-click transactions with any… · decent.xyz | acquired |
| 2018-06-01 | YCOptic Making APIs Developer-friendly · useoptic.com | acquired |
| 2024-01-01 | YCInteguru Generate fast, reliable APIs for any platform · integuru.com | still up |
| 2025-09-01 | YCLapis AI that creates and runs ads, end-end · trylapis.com | still up |
| 2021-01-01 | YCPensil New-Age White Label Community Platform SDKs and APIs for Games,… · pensil.in | gone |
| 2012-01-01 | YCSlidePay Banking and Payment Platform APIs. Exited October 2014. · angel.co | acquired |
| 2018-06-01 | YCOneGraph GraphQL API to connect all of the internet's APIs. Join us at Netlify! · onegraph.com | acquired |
| 2017-06-01 | Natural language processing APIs for developers. · plasticity.ai | acquired |
| 2026-06-01 | APIs for robotics data teams to verify data quality for model training · hebbianrobotics.com | still up |
| 2026-01-01 | Agentic Payments for APIs · orthogonal.com | still up |
| 2026-01-01 | YCZatanna Turning all software into agent-first APIs · zatanna.ai | still up |
| 2023-01-01 | YCSuperAPI Programmable API gateway that makes APIs cacheable · trysuperapi.com | still up |
| 2025-09-01 | API for parsing multimodal unstructured data · unsiloed.ai | still up |
| 2026-06-01 | We give AI agents realtime web context via API · context.dev | still up |
| 2024-09-01 | Empowering Physical Therapists to Go Independent · joinhealthspark.com | still up |
| 2012-06-01 | YCEligible Insurance Billing APIs for Healthcare Businesses · eligible.com | still up |
| 2013-06-01 | Banking APIs; acquired by Silicon Valley Bank in August 2015 · standardtreasury.com | acquired |
| 2021-01-01 | YCWaypoint The email API built for product teams · usewaypoint.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.