
reCAPTCHA
hCaptcha
Cloudflare Turnstile
Akismet
Private Captcha
mosparo
Cap Captcha
ALTCHA is a free CAPTCHA alternative that uses a proof-of-work mechanism to protect your website, and online services from spam.

With Cozystack, you can transform your bunch of servers into an intelligent system with a simple REST API for spawning Kubernetes clusters, Database-as-a-Service, virtual machines, load balancers, HTTP caching services, and other services with ease.

Which is more popular?
Based on our record, ALTCHA seems to be more popular. It has been mentioned 3 times since March 2021.
Website, pricing, platforms and company facts side by side.
|
|
|
|
|---|---|---|
| Website | altcha.org | cozystack.io |
| Pricing | ||
| Platforms | — | |
| Listed in |
In their own words, as submitted to SaaSHub.


ALTCHA uses a proof-of-work mechanism to protect your website, APIs, and online services from spam and unwanted content. Unlike other solutions, ALTCHA is free, open-source and self-hosted, without external services, does not use cookies nor fingerprinting, does not track users, and is fully...
No description of Cozystack yet.
What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


No analysis of ALTCHA yet.
Overall verdict
Why this product is good
Recommended for
Walkthroughs and reviews on video.
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing ALTCHA and Cozystack.
ALTCHA's answer
What makes ALTCHA unique is that it is free, open-source and self-hosted, without external services, does not use cookies nor fingerprinting, does not track users, and is fully compliant with GDPR. Unlike other captcha solutions, ALTCHA does not require users to solve puzzles or captchas and uses a proof-of-work mechanism instead.
ALTCHA's answer
Here are some key reasons why a person should choose ALTCHA over its competitors:
So in summary, ALTCHA's privacy compliance, open design, accessibility, machine compatibility and modern approach give it clear advantages over competing captcha solutions.
ALTCHA's answer
JavaScript and Svelte.
ALTCHA's answer
Our primary audience for ALTCHA Forms includes enterprises, medium and small businesses, non-profits, and individuals who need a reliable, secure, and compliant solution for data collection and management. Whether you're a large corporation dealing with extensive regulatory requirements, a small business looking to protect customer and employee data, a non-profit organization managing sensitive information, or an individual seeking robust data security, ALTCHA Forms provides the tools and features necessary to meet your needs. With a focus on compliance, user-friendly design, and advanced security measures, our platform is tailored to support diverse users in navigating complex regulatory landscapes and ensuring data protection.
Share your experience with using ALTCHA and Cozystack. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


The captcha on orkestr is Altcha. Self-hosted, no third-party JS, no Google, no behavioral tracking. Users don't see a puzzle. There's a single checkbox and a quiet "verifying..." while the browser does some math. About a second, total. - Source: dev.to / 4 months ago
Here's how PoW works for form protection (using the ALTCHA wire format):. - Source: dev.to / 5 months ago
Go based, similar to JS based ALTCHA https://altcha.org/ discussed at https://news.ycombinator.com/item?id=43971068. - Source: Hacker News / 9 months ago
Tracking Cozystack since Feb 2024.
When comparing ALTCHA and Cozystack, you can also consider the following products.

reCAPTCHA is a free security service that protects your websites from spam and abuse.
Compare reCAPTCHA to ALTCHA or Cozystack:

Do you use a captcha to keep out bots? hCaptcha is a drop-in replacement for reCAPTCHA that earns website owners money and helps companies get their data labeled.
Compare hCaptcha to ALTCHA or Cozystack:

Cloudflare's service for any company to replace CAPTCHAs and deliver a better experience to web visitors.
Compare Cloudflare Turnstile to ALTCHA or Cozystack:

Akismet is a spam fighting service that protects millions of WordPress sites from comment and contact form spam.
Compare Akismet to ALTCHA or Cozystack:

Independent, privacy-first, self-hostable CAPTCHA service made in EU
Compare Private Captcha to ALTCHA or Cozystack:
