
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.

NovoPsych
Clinical assessment tools for psychologists, therapists and occupational therapists. Send measures by secure link and review scored results, severity bands and reports.

Which is more popular?
Based on our record, ALTCHA seems to be more popular. It has been mentioned 4 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | altcha.org | clientforms.app |
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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...
Clinical assessment tools for psychologists, therapists and occupational therapists. Send measures such as the PHQ-9, GAD-7 and DASS-21 by secure link and get scored results, severity bands and reports ready to review. The catalogue also includes DSM-5 ADHD assessments and autism screening tools....
What each product offers, as listed by its team.


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


As answered by people managing ALTCHA and ClientForms.app.
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.
ClientForms.app's answer:
Neurodivergent-first design. Most digital forms just replicate paper online. ClientForms is built specifically for ADHD and autism patients - progress bars with time remaining (helps with time blindness), softer colours instead of harsh white, sticky headers so you always know where you are. The forms are designed to reduce anxiety and improve completion rates.
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.
ClientForms.app's answer:
Most clinical software treats patients as an afterthought. ClientForms is designed specifically for neurodivergent users who are filling out the forms, progress indicators, time estimates, calmer colours, predictable layouts. One link, no signup required, works on any device. Patients just open and complete.
ALTCHA's answer
JavaScript and Svelte.
ClientForms.app's answer:
Frontend: Next.js 15 (React 19), Tailwind CSS Backend: Supabase (PostgreSQL, Row-Level Security) Authentication: Clerk Payments: Stripe Hosting: Vercel (Sydney region) Database hosting: Supabase (Australian data residency)
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.
ClientForms.app's answer:
Psychologists who assess ADHD and autism. Typically private practice, solo or small group (1-5 clinicians), currently using paper forms and spending hours on admin per assessment. They want something that works and is secure.
Share your experience with using ALTCHA and ClientForms.app. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


ALTCHA won on the boring things. It is open source, self-hosted and collects nothing, and it ships official libraries in both Go and PHP, the two languages our two layers already speak. So the same protocol runs twice on every store, by... - Source: dev.to / about 1 month ago
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 / 6 months ago
Here's how PoW works for form protection (using the ALTCHA wire format):. - Source: dev.to / 8 months ago
Tracking ClientForms.app since Dec 2025.
When comparing ALTCHA and ClientForms.app, you can also consider the following products.

reCAPTCHA is a free security service that protects your websites from spam and abuse.
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NovoPsych is a tool that is used for outcome monitoring via conducting psychological tests online.
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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.
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Cloudflare's service for any company to replace CAPTCHAs and deliver a better experience to web visitors.
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Akismet is a spam fighting service that protects millions of WordPress sites from comment and contact form spam.
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Independent, privacy-first, self-hostable CAPTCHA service made in EU
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