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for websites and APIs.


ALTCHA’s Spam Filter is like a good robot, automatically classifying user-submitted data and intercepting spam before it reaches you.

Improve Accessibility and Eliminate Spam

Invisible Protection

Integrate a truly invisible spam protection without Captchas on your server.

Better Conversions

Increase user conversion rates by eliminating Captchas from your website.

Highly Accurate

Achieve reliable classification through methodical analysis of input data.

Email Validation

Detect fake or suspicious email addresses and distinguish between "free" and "work" emails.

IP Address Validation

Identify whether an IP address is associated with a data center, proxy, or TOR exit for malicious activity.


Effectively block certain countries, regions, or continents from accessing or using your website or APIs.

Privacy-Focused Solution

All our services, including the Spam Filter, prioritize privacy and comply with GDPR and CCPA data privacy regulations. ALTCHA’s Spam Filter is custom-built and hosted privately in the EU and USA. Importantly, it does not use or rely on commercial services like ChatGPT or similar AI technologies, and we do not share your data with any third parties.

More about compliance

Akismet vs. Spam Filter

Based on the latest Anti-Spam Report and comprehensive testing,
ALTCHA’s Spam Filter outperforms in both speed and accuracy.

2.62 ×
2.17 ×
more accurate
100 ×
more privacy

See how ALTCHA Spam Filter compares to Akismet, CleanTalk, ChatGPT and others in the report.

Read the full report

Methodical Data Analysis

Instead of relying on traditional machine learning algorithms, ALTCHA’s Spam Filter utilizes a methodical analysis of input data. This approach thoroughly examines text, email addresses, and IP addresses using sophisticated rules, ensuring reliable and predictable data classification without unexpected results.

With Super-Easy Integration

Using the Widget

ALTCHA’s Widget combined with the Spam Filter simplifies the process with minimal setup on your server.

When set up with the Widget, the Spam Filter checks data before it’s sent to your server. This helps improve user experience by giving immediate feedback on potential spam, allowing users to correct their input.

Integrate Widget or Read Tutorial

Using the API

For straightforward spam protection, use the API to check for spam directly on your server.

Integrate API

fetch('', {
body: JSON.stringify({
email: '',
ipAddress: '',
text: 'To spam or not to spam...'
headers: {
'authorization': 'Bearer ...',
'content-type': 'application/json',
'referer': ''
method: 'POST',

Versatile Use Cases

Safeguarding your websites and applications.

ALTCHA Spam Filter is a comprehensive solution designed to protect your digital assets from spam and abuse. Utilizing real-time data analysis, the Spam Filter detects and blocks spam before it reaches your system. This proactive approach ensures a clean, user-friendly environment, keeping your websites, APIs, and applications secure and efficient.

Highly customizable, ALTCHA Spam Filter can be tailored to fit your specific requirements, whether you’re managing simple contact forms or complex transactional data.


Prevent spam from infiltrating your website forms, ensuring clean and reliable data collection.


Automatically filter out spam from comments, reviews, and other user-generated content, maintaining the integrity of your site's interactions.


Identify and block malicious actors and fake accounts with robust email validations and IP-related checks, including geo-location analysis.


Reduce chargebacks and fraudulent transactions, ensuring a safer and more secure shopping experience for your customers.


Reliable and affordable spam protection.

Our Spam Filter is available as a SaaS product through an API service. For users of ALTCHA Forms, the Spam Filter is included in your plan, with API requests available according to your plan’s configuration.

If you prefer to use only the Spam Filter API without ALTCHA Forms, check out our AntiSpam plans.

Try ALTCHA Forms

Discover how ALTCHA Forms seamlessly integrates our anti-spam solutions, including access to the Spam Filter API.

Explore Forms

Estimate API Calls

Adjust the slider to match your expected volume of form submissions you want to check for spam.

Protecting your forms also with the ALTCHA's Widget requires twice the amount of API calls.

Submissions: 0 / month
Estimated API calls: 0 / month
Recommended plan:

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OSS hosted on GitHub • Website made with Astro Starlight.

Crafted in EU, with Europeans in mind.
Hosted in Germany. USA region available.

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