Hackernews posts about W21

W21 is a year class in Y Combinator's (YC) accelerator program, indicating that these are startups that were part of the Winter 2021 batch.

1. Show HN: A simple Hackernews client for iOS and Android (github.com)
   40 points by trevor-e 14 days ago | 5 comments
2. Launch HN: A0.dev (YC W25) – React Native App Generator
   263 points by sethburster 10 days ago | 97 comments
3. Launch HN: Karsa (YC W25) – Buy and save stablecoins internationally
   129 points by Shasnani 22 days ago | 224 comments
4. Launch HN: Confident AI (YC W25) – Open-source evaluation framework for LLM apps
   109 points by jeffreyip 1 day ago | 25 comments
5. Launch HN: Promptless (YC W25) – Automatic updates for customer-facing docs
   106 points by prithvi2206 3 days ago | 60 comments
6. Launch HN: Pinch (YC W25) – Video conferencing with immersive translation
   72 points by christiansafka 17 days ago | 43 comments
7. Launch HN: Roark (YC W25) – Taking the pain out of voice AI testing
   60 points by zammitjames 4 days ago | 29 comments
8. Show HN: CopyCat (YC W25) – Free Alternative to OpenAI's $200 Operator (www.runcopycat.com)
   34 points by gsabin 28 days ago | 19 comments
9. Launch HN: Massdriver (YC W22) – Self-serve cloud infra without the red tape
   33 points by coryodaniel about 5 hours ago | 37 comments
10. Show HN: Helicone (YC W23) – OSS LLM Observability and Development Platform (github.com)
    29 points by justintorre75 29 days ago | 7 comments
11. AI and WW1 Aerial Balloon Photos 1916-1918 (reticulated.net)
    1 points by pwillia7 1 day ago | discuss
12. WG21 C++ Committee Meeting Report, Hagenberg 2025 (old.reddit.com)
    1 points by quuxplusone 1 day ago | discuss
13. Boom (YC W16) On starting and scaling aerospace company (www.ycombinator.com)
    1 points by vednig 24 days ago | discuss
14. Show HN: A pure TypeScript library for editing videos in the Browser (github.com)
    3 points by K9-P5 about 7 hours ago | discuss
15. F-strings for C++26 proposal [pdf] (www.open-std.org)
    183 points by HeliumHydride 19 days ago | 213 comments
16. Show HN: Quiz Me GPT: AI generated trivia questions for any topic you choose (wd13.ca)
    2 points by willd13 10 days ago | discuss
17. The Impact of the 2018 Trade War on U.S. Prices and Welfare (2019) (www.nber.org)
    2 points by throw0101d 11 days ago | discuss
18. F-strings proposal for C++26 [pdf] (www.open-std.org)
    2 points by HeliumHydride 20 days ago | discuss
19. Battery offers six months of standby (www.theverge.com)
    1 points by pawurb 1 day ago | 1 comments
20. AI and WWI Aerial Balloon Photos 1916-1918 (reticulated.net)
    1 points by pwillia7 about 8 hours ago | discuss
21. Clojure 1.12 Overview [video] (www.youtube.com)
    1 points by tosh 12 days ago | discuss
22. I read every 1990s Cypherpunk email (docs.google.com)
    1 points by rapawel 20 days ago | discuss
23. Is DeepSeek just a tip of a disruptive iceberg? (instagram.flis11-2.fna.fbcdn.net)
    1 points by NatalijaAAD 24 days ago | discuss
24. YC Graveyard: 821 inactive Y Combinator startups (ycgraveyard.iamwillwang.com)
    384 points by memalign 27 days ago | 231 comments
25. 21st Century C++ (cacm.acm.org)
    177 points by bandwitch 16 days ago | 269 comments
26. 21st Century C++ (cacm.acm.org)
    109 points by steveklabnik 16 days ago | 2 comments
27. LLM Hallucination Benchmark: R1, o1, o3-mini, Gemini 2.0 Flash Think Exp 01-21 (github.com)
    17 points by zone411 11 days ago | 3 comments
28. The Phantom T2110 High-Speed Camera Records at 483,300 FPS (petapixel.com)
    7 points by PaulHoule 16 days ago | discuss
29. An Arctic 'beyond recognition' by 2100 (www.colorado.edu)
    6 points by geox 14 days ago | discuss
30. Epsio Outperforms Apache Flink by Up to 21x on TPC-DS Dataset (www.epsio.io)
    4 points by dkgs1998 23 days ago | 1 comments