<!doctype html><htmllang=en-us><head><metacharset=utf-8><metahttp-equiv=x-ua-compatiblecontent="ie=edge"><metaname=viewportcontent="width=device-width,initial-scale=1,shrink-to-fit=no"><linkrel=preloadas=fonthref=/fonts/vendor/jost/jost-v4-latin-regular.woff2type=font/woff2crossorigin><linkrel=preloadas=fonthref=/fonts/vendor/jost/jost-v4-latin-700.woff2type=font/woff2crossorigin><linkrel=stylesheethref=/main.1d7b9bbcf00913c73e2065e39eee858e0f46e4df74991d5a1e752637e5e62952ca719c4211dfa5893caa677fed84c424a249acaa289e0d7274c90a024fb35e1f.cssintegrity="sha512-HXubvPAJE8c+IGXjnu6Fjg9G5N90mR1aHnUmN+XmKVLKcZxCEd+liTyqZ3/thMQkokmsqiieDXJ0yQoCT7NeHw=="crossorigin=anonymous><noscript><style>img.lazyload{display:none}</style></noscript><metaname=robotscontent="index, follow"><metaname=googlebotcontent="index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1"><metaname=bingbotcontent="index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1"><title>mCaptcha - mCaptcha</title><metaname=descriptioncontent="mCaptcha is proof-of-work based captcha system that is privacy focussed and fully automated."><linkrel=canonicalhref=/><metaname=twitter:cardcontent="summary_large_image"><metaname=twitter:imagecontent="//static/images/landing.jpg"><metaname=twitter:titlecontent="Defend Like Castles"><metaname=twitter:descriptioncontent="mCaptcha is proof-of-work based captcha system that is privacy focussed and fully automated."><metaname=twitter:sitecontent="@"><metaname=twitter:creatorcontent="@"><metaproperty="og:title"content="Defend Like Castles"><metaproperty="og:description"content="mCaptcha is proof-of-work based captcha system that is privacy focussed and fully automated."><metaproperty="og:type"content="website"><metaproperty="og:url"content="/"><metaproperty="og:image"content="//static/images/landing.jpg"><metaproperty="og:updated_time"content="2021-03-09T00:00:00+00:00"><metaproperty="og:site_name"content="mCaptcha"><metaproperty="article:publisher"content="https://www.facebook.com/"><metaproperty="article:author"content="https://www.facebook.com/"><metaproperty="og:locale"content="en_US"><linkrel=alternatetype=application/rss+xmlhref=/index.xml><scripttype=application/ld+json>{"@context":"http://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"\/"}]}</script><metaname=theme-colorcontent="#fff"><linkrel=apple-touch-iconsizes=180x180href=/apple-touch-icon.png><linkrel=icontype=image/pngsizes=32x32href=/favicon-32x32.png><linkrel=icontype=image/pngsizes=16x16href=/favicon-16x16.png><linkrel=manifesthref=/site.webmanifest></head><bodyclass=home><divclass="header-bar fixed-top"></div><headerclass="navbar fixed-top navbar-expand-md navbar-light"><divclass=container><inputclass="menu-btn order-0"type=checkboxid=menu-btn>
<spanclass=toggle-dark><svgxmlns="http://www.w3.org/2000/svg"width="20"height="20"viewBox="0 0 24 24"fill="none"stroke="currentcolor"stroke-width="2"stroke-linecap="round"stroke-linejoin="round"class="feather feather-moon"><pathd="M21 12.79A9 9 0 1111.21 3 7 7 0 0021 12.79z"/></svg></span><spanclass=toggle-light><svgxmlns="http://www.w3.org/2000/svg"width="20"height="20"viewBox="0 0 24 24"fill="none"stroke="currentcolor"stroke-width="2"stroke-linecap="round"stroke-linejoin="round"class="feather feather-sun"><circlecx="12"cy="12"r="5"/><linex1="12"y1="1"x2="12"y2="3"/><linex1="12"y1="21"x2="12"y2="23"/><linex1="4.22"y1="4.22"x2="5.64"y2="5.64"/><linex1="18.36"y1="18.36"x2="19.78"y2="19.78"/><linex1="1"y1="12"x2="3"y2="12"/><linex1="21"y1="12"x2="23"y2="12"/><linex1="4.22"y1="19.78"x2="5.64"y2="18.36"/><linex1="18.36"y1="5.64"x2="19.78"y2="4.22"/></svg></span></button><ulclass="navbar-nav social-nav order-3 order-md-5"><liclass=nav-item><aclass=nav-linkhref=https://github.com/mCaptcha><svgxmlns="http://www.w3.org/2000/svg"width="20"height="20"viewBox="0 0 24 24"fill="none"stroke="currentcolor"stroke-width="2"stroke-linecap="round"stroke-linejoin="round"class="feather feather-github"><pathd="M9 19c-5 1.5-5-2.5-7-3m14 6v-3.87a3.37 3.37.0 00-.94-2.61c3.14-.35 6.44-1.54 6.44-7A5.44 5.44.0 0020 4.77 5.07 5.07.0 0019.91 1S18.73.65 16 2.48a13.38 13.38.0 00-7 0C6.27.65 5.09 1 5.09 1A5.07 5.07.0 005 4.77 5.44 5.44.0 003.5 8.55c0 5.42 3.3 6.61 6.44 7A3.37 3.37.0 009 18.13V22"/></svg><spanclass="ms-2 visually-hidden">GitHub</span></a></li></ul><divclass="collapse navbar-collapse order-4 order-md-1"><ulclass="navbar-nav main-nav me-auto order-5 order-md-2"><liclass=nav-item><aclass=nav-linkhref=/about/>About</a></li><liclass=nav-item><aclass=nav-linkhref=/blog/>Blog</a></li><liclass=nav-item><aclass=nav-linkhref=/community/>Community</a></li><liclass=nav-item><aclass=nav-linkhref=/contact/>Contact</a></li><liclass=nav-item><aclass=nav-linkhref=/docs/prologue/introduction/>Docs</a></li></ul><divclass="break order-6 d-md-none"></div><formclass="navbar-form flex-grow-1 order-7 order-md-3"><inputid=userinputclass="form-control is-search"type=searchplaceholder="Search docs..."aria-label="Search docs..."autocomplete=off><divid=suggestionsclass="shadow bg-white rounded"></div></form></div></div></header><divclass="wrap container"role=document><divclass=content><sectionclass="section container-fluid mt-n3 pb-3"><divclass="row justify-content-center"><divclass="col-lg-12 text-center"><h1class=mt-0>Defend Like Castles</h1></div><divclass="col-lg-9 col-xl-8 text-center"><pclass=lead>mCaptcha is proof-of-work based captcha system that is privacy focussed and fully automated.</p><aclass="btn btn-primary btn-lg px-4 mb-2"href=/docs/prologue/introduction/role=button>Get started</a><pclass=meta>Libre software <ahref=https://github.com/mCaptcha>GitHub</a></p></div></div></section></div></div><sectionclass="section section-sm"><divclass=container><divclass="row justify-content-center text-center"><divclass=col-lg-5><h2class=h4>Privacy focused</h2><p>Doesn't track, doesn't profile your users.</p></div><divclass=col-lg-5><h2class=h4>Robust and Accurate</h2><p>Got users behind <ahref=https://en.wikipedia.org/wiki/Network_address_translation>NATs</a>? No issues. We don't use IP address for rate-liming. NAT or not you get the mCaptcha experience.</div><divclass=col-lg-5><h2class=h4>Best-in-class UX</h2><p>mCaptcha is silent, so silent that your users won't even feel it. No more anoying imgaes, no more helping for Big Brothers with their ML stuff</p></div></div><divclass="row justify-content-center text-center"><divclass=col-lg-5><h2class=h4>Defend like castles</h2><p>Our <ahref=https://en.wikipedia.org/wiki/Proof_of_work>PoW</a>-based solution defends fiersly. mCaptcha makes attacking your site more experience than what it will take for you to respond to the attacker's requests</p></div><divclass=col-lg-5><h2class=h4>Libre Soft
