The Best Cap Alternatives in 2026

Cap offers an open-source, self-hosted CAPTCHA alternative using proof-of-work and instrumentation challenges.

Add proof-of-work verification to websites with mCaptcha, a privacy-focused automated CAPTCHA system.

Build self-hosted, privacy-respecting CAPTCHA flows with the LibreCaptcha framework.

Add a proof-of-work CAPTCHA system to an application using the mCaptcha backend component.

BlackVault protects AI API credentials with rate limits, budget caps, model restrictions, and an emergency kill switch.

Run a privacy-focused home security camera system with support for multiple USB or Raspberry Pi cameras.

Store, generate, and organize one-time password codes with 2FAuth, a self-hosted manager for individuals and teams.

Solve reverse engineering challenges published on challenges.re, a challenge-focused site.

Inspect iOS and macOS applications with Malimite, a decompiler project hosted on GitHub.

Manage two-factor authentication codes with OTP Auth, an iOS app listed on the App Store.

Generate secure SSL configurations for selected web, database, and mail software.

SSL for Free provides SSL and wildcard certificates for enabling HTTPS on websites.

Let’s Encrypt is a nonprofit that provides automated TLS certificates for securing websites with HTTPS.

GoPlus offers Web3 security tools including audits, APIs, a user security hub, and a browser extension.

Search the National Vulnerability Database, a public resource for vulnerability information.

WhatsMyDNS checks DNS record propagation across global resolvers for record types including A, AAAA, MX, and TXT.

Find which websites support two-factor authentication and what methods they offer in this directory.

View Toronto Police calls for service on a map that updates in real time, according to the supplied page description.

Use Metasploit to find security issues, verify mitigations, and manage authorized penetration testing assessments.

The Snyk Security Database provides vulnerability details and remediation guidance for packages and cloud configurations.

The URL Decoder and Encoder converts text between encoded and decoded forms, including JavaScript URLs.

Lucia was deprecated in March 2025. The website was updated in July 2026 and points to code/auth_session.ts as a single-file replacement for the NPM package and to the Auth Book for auth information.

Pulsedive provides threat intelligence tools to search, scan, and enrich IP addresses, URLs, domains, and other indicators.

DNSPerf compares the performance and uptime of enterprise and commercial DNS providers.