Best Free CAPTCHA Software

Turnstile delivers frustration-free, CAPTCHA-free web experiences to website visitors - with just a simple snippet of free code. Moreover, Turnstile stops abuse and confirms visitors are real without the data privacy concerns or awful UX that CAPTCHAs thrust on users. Give your web visitors an even better experience. Turnstile confirms they are real with no visual puzzle - totally transparent to visitors. Turnstile always preserves the privacy of web visitors on your site - without sacrificing effectiveness. Unlike other CAPTCHA options, we never harvest data for ad retargeting. Deploy in minutes with just a quick code snippet - and totally free of charge. Humans spend about 500 years each day solving CAPTCHAs - wasting time and creating frustration. This is why Cloudflare built a better alternative to CAPTCHAs with Managed Challenge and now Turnstile.

MTCaptcha is a smart captcha service that prioritizes privacy and accessibility. It offers an adaptive invisible noCaptcha that is easy for humans but hard for bots, making verification frictionless. MTCaptcha is GDPR and WCAG compliant, ensuring that your data is never sold or shared with third parties. The captcha images are certified colorblind safe and the widget is fully VPAT compliant and optimized for screen readers. MTCaptcha supports any language and can be fully customized to match any webpage. It also supports audio in captcha, making it accessible to users who are visually impaired. MTCaptcha is trusted by Enterprises, Government, NGOs worldwide and is available in all the major world languages. MTCaptcha works around the world, including in China, making it a truly global captcha solution. It is backed by an adaptive Risk Engine that monitors and responds to threats, making it difficult for bots but easy for humans.

ALTCHA is a modern security and privacy-focused platform built to defend web services from bots and abuse — without compromising the user experience. At the heart of its ecosystem is ALTCHA Sentinel, a next-generation threat detection and mitigation system designed to protect websites, APIs, and applications from automated attacks, spam, and other forms of abuse. ALTCHA Sentinel stands out by combining adaptive machine learning, behavioral analysis, and smart verification techniques. It doesn’t rely on intrusive CAPTCHAs or outdated blocking tactics; instead, it works invisibly behind the scenes, analyzing traffic patterns in real time to identify and stop threats before they cause harm. Sentinel protects critical entry points like sign-up forms, login pages, and comment sections — all while keeping the experience seamless for real users.

Organizations—from startups to large enterprises—use Friendly Captcha to protect their websites and online services from spam and abuse. Friendly Captcha respects your user’s privacy and works automatically, so your users don’t have to do anything. Based on the underlying mechanisms of the blockchain, Friendly Captcha employs a fundamentally new approach to securely defend your websites and online services from spam and bots. Friendly Captcha does not depend on tracking your users and exploiting personal data. Plus, your users no longer have to deal with tedious labeling tasks. They don’t have to do anything at all.

Dynamic & PoW CAPTCHA: Real-Time Bot & Cyber Threat Defense | Prosopo Procaptcha Prosopo Procaptcha provides comprehensive protection against various automated threats, including web scraping, credential stuffing, account takeover attempts, clicks fraud, distributed denial of service (DDoS) attacks, inventory hoarding, credit card fraud, and other forms of malicious bot activity that can harm your online business or compromise user data. With no hidden fees and transparent pricing, our solution provides an affordable alternative to expensive services like reCAPTCHA and hCaptcha. Procaptcha dynamically evaluates user interactions by analyzing browser environments and behavior. Based on risk scores, it automatically applies the appropriate challenge, making it difficult for bots to bypass while ensuring a smooth experience for real users.

BotDetect™ CAPTCHA generator is a non-stalking form-security solution that uses a mix of measures, that are easy for humans but hard for bots, to prevent automated form posting. BotDetect also provides an audio Captcha alternative to keep websites accessible to people with impaired vision, enabling you to make WCAG and Section 508 compliant websites. The years of Google’s relentless abuses of their organic and paid search monopolies, and the years of their equally relentless campaign of disinformation and FUD about captchas, took a toll among our former competitors there are only two viable players left. During its first decade, BotDetect was unique among Captcha generators in offering many different Captcha image and sound algos. While each of them was easily comprehensible to humans, the random use of multiple Captcha generation algos made the generated captchas extremely difficult to pass automatically.

The TextCaptcha service provides access to textual CAPTCHA challenges via a simple JSON or XML API over HTTP. The question is the textual challenge that should be presented to the user. The answers are the MD5 hashes of correct lower cased answers: you should be able to check responses from real users you challenge with the question against these checksums. A text CAPTCHA is more accessible to visually impaired users than their image-based alternatives like ReCAPTCHA. Using text is also more flexible if for example you need to present the challenge over a text-only channel like SMS or IRC. The problem with text CAPTCHAs is that they provide inherently more information than a distorted image. They are parseable, under the right conditions solveable. With the advent of contextual parsing tools such as Wolfram Alpha, such simple logic puzzles have become easier to solve programatically.

Online businesses rely on CaptchaFox to defend and safeguard their website and services against automated bot attacks. CaptchaFox protects against account takeover, credential stuffing, spam and scalping while complying with global privacy laws, such as GDPR, CCPA, and more. Through minimized data collection and retention during verification, the privacy of your users is always preserved. CaptchaFox utilizes a variety of data signals and dynamic response challenges to verify the authenticity of visitors without the use of cookies or trackers. The challenges have low friction and are easy for humans to solve but difficult for bots. The service is available in multiple languages and scales to incoming traffic through our global infrastructure. Enterprise customers can access advanced threat insights to achieve complete risk awareness.

TrustCaptcha protects your website from bots and spam—without frustrating users. Unlike traditional CAPTCHAs that rely on image puzzles and clicks, TrustCaptcha works invisibly in the background. It activates as users type, completing before they hit submit—reducing bounce rates and improving conversions. Behind the scenes, a smart trust scoring system evaluates each request, while a lightweight proof-of-work mechanism makes spam attacks costly for bots but unnoticeable for real users. This combination blocks abuse without disrupting the user experience. Fully GDPR-compliant and customizable, TrustCaptcha lets you adjust language, design, and visibility—even run it completely hidden. Integration is fast with clear documentation and support for major frameworks. Choose between fixed pricing or pay-per-use, so you only pay for what you need. TrustCaptcha delivers secure, seamless protection that boosts performance—not friction.

CaptchaText is 100% FREE, built on a revolutionary ZERO database architecture, powered by a proprietary Hybrid In-Memory Indexing (Hybrid IMI) engine algorithm, that enables CAPTCHA authentication to be performed using minimal data bits against server memory. CaptchaText's multi-layered security approach includes real-time IP verification, sophisticated bot detection algorithms, and intelligent token management that adapts to your traffic patterns. With support for 23 languages and flexible customization options, CaptchaText seamlessly integrates into any website while providing robust protection against automated threats. Experience the power of advanced security without any cost limitations, powered by a revolutionary Zero Database architecture and proprietary Hybrid In-Memory Indexing engine. This cutting-edge technology enables CaptchaText to provide enterprise-grade protection at unprecedented efficiency, allowing to offer their complete feature set at no cost. By eliminating