Cap is a fast, lightweight, and modern open-source CAPTCHA alternative based on SHA-256 proof-of-work (PoW). It’s 250x smaller than hCaptcha, privacy-focused, fully customizable, and easy to self-host. Cap helps prevent spam and abuse without tracking users, making it ideal for privacy-conscious developers. Built for speed and simplicity, Cap is perfect for modern web apps, forms, and APIs that need secure, lightweight human verification.
DiffSense
Interesting! How does it work? How does it verify i'm a human?
Cap
@sentry_co it uses private, accessible proof-of-work. you can read more on the docs
DiffSense
@tr3 Very interesting! Forgive me! But I did not understand the problem and the solution here. So I asked perplexity. It came up with a pretty good answer: https://www.perplexity.ai/search/how-does-this-technology-work-GRfvnIltTXKObXZPQBvVaA#0 Maybe some content for your readme docs to make it more succinct?
One question remains. So the PoW algo. Makes it prohibitive for bots to cheat the captcha. How much cost does it penalize bots with? is this CPU watts or? Like 0.1$ in computation?
And do you think this is the future of captcha? Mine some "bitcoins", to fight bots?
Cap
@sentry_co hi there, you should read the effectiveness page, it explains much more in detail: https://capjs.js.org/guide/effectiveness.html
just like training AIs or mining bitcoin is expensive, so is solving a huge quantity of proof-of-work. i recommend checking https://www.researchgate.net/publication/374638786_Proof-of-Work_CAPTCHA_with_password_cracking_functionality
DiffSense
@tr3 It doesnt say anything about how much cost is incurred on the bots. Some transparency around this would be gold. Also Does it increase the difficulty of the challenge on repeated attempts? If not, may this be a future feature? The research paper you linked to describes a password cracking functionality. Is cap used for this purpose? That raises ethical dilemma, and End user legal dilemmas. Also how does it perform on mobile devices with limited computational resources and battery? Some transparency around this would also be great. Btw. I think this project is really cool! So that's why I'm curious. 😸 I also asked pplx regarding the research paper. And it echoed some of the questions: https://www.perplexity.ai/search/what-are-some-of-the-pros-and-uy_EbHZ1TsSlpMGSkFVTXw#0
Migma AI
We'll use this, looks so good and modern. Can we customize the style?
Cap
@migma yep! everything is customizable through css variables
I like the lightweight and privacy-focused approach! 😄
SyncSignature
That looks great!
Cap
@neelptl2602 thank you!
Pontoon
Congrats on the launch, looks great!
really cool. upvoted
kool