Altcha

Altcha is a Craft CMS plugin that protects your forms with ALTCHA proof-of-work spam protection. A visitor's browser solves a small cryptographic challenge instead of picking out traffic lights, and the whole exchange stays on your own site — the challenge is issued and verified by your Craft install, with no third-party service, no cookies, and no tracking to disclose under GDPR.

Features

• Formie captcha — registers as a native captcha in Formie, switched on per form from Formie's own captcha settings, with the widget injected into the form for you.
• Integrations for Craft's form plugins — Comments, Contact Form, Guest Entries, and Craft's own registration, login, and forgot-password forms, each behind its own toggle.
• Blanket mode — enforce a solved challenge on any front-end POST you list by action path, for form plugins with no captcha API of their own.
• Replay protection — a solved payload is accepted exactly once, so a captured submission can't be posted again.
• Environment-backed HMAC key — generate a signing key with a console command and reference it from your .env, so the secret never lands in project config.
• The widget ships with the plugin — ALTCHA's widget v3 is vendored into the plugin's asset bundle, so nothing loads from a CDN.
• Per-widget options — override the display mode, theme, auto-solve behavior, or any other widget attribute for a single form.
• Inert until you say so — every integration is off by default, so installing the plugin changes nothing about your site until you opt a form in.

Documentation

Visit the repository README for all documentation on usage and configuration.