
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.

Lasso Moderation
Moderation API
CleanSpeak
Sightengine
ContentAnalyzer.ai
Trusted Content Decisions, Powered by AI.
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.
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| Website | altcha.org | checkstep.com |
| Pricing | — | |
| Platforms | — | |
| Company | — | Startup from the United Kingdom · 20 - 49 employees |
| 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...
Checkstep is an AI content moderation platform built for Trust and Safety teams at scale. The platform scans text, images, video and audio, applies a configurable policy engine covering every major abuse type, and routes edge cases to human moderators through review queues. Its AI Marketplace...
What each product offers, as listed by its team.


How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing ALTCHA and Checkstep.
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 Checkstep. 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 / 6 months ago
Go based, similar to JS based ALTCHA https://altcha.org/ discussed at https://news.ycombinator.com/item?id=43971068. - Source: Hacker News / 10 months ago
Tracking Checkstep since Sep 2026.
When comparing ALTCHA and Checkstep, 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 Checkstep:

Content moderation tooling out of the box. Easily moderate your content with the help of AI, custom automation and an easy to use dashboard.
Compare Lasso Moderation to ALTCHA or Checkstep:

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 Checkstep:

Content moderation is tedious and time-consuming. The Moderation API uses artificial intelligence to analyze, detect, extract and even cover up all the kinds of data you rely on. Spend less time moderating with an AI-powered solution.
Compare Moderation API to ALTCHA or Checkstep:

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

Keep inappropriate content and trolls out of your community
Compare CleanSpeak to ALTCHA or Checkstep: