The Best Data Structure : Infix Postfix Prefix - Converter & Evaluator Alternatives in 2026

Ndiff compares Nmap scan results from two XML files, showing changes such as hosts and ports appearing or disappearing.

Manage two-step verification tokens on Android with Aegis Authenticator, a free, open-source app.

Big Number Calculator evaluates very large mathematical expressions in a web browser.

This browser-based converter turns user-supplied text into an image file for downloading or use in other documents.

Threat Radar displays current cyber threat intelligence on a live map, showing security activity from its data sources.

The action firewall for AI agents. Enforce policy and human approval before risky tool calls, shell commands, workflows, and production changes, with auditable evidence.

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.

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

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.

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

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

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.

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

Search a community-curated collection of bug bounty writeups and learning resources.

UUID Tools generates individual or bulk UUIDs and supports multiple UUID versions.

Test a browser for privacy leaks, including exposed IP addresses, device information, and fingerprinting risks.

Fraunhofer FKIE maintains Malpedia, a reference that organizes information about malware families.

Discover hosts and map networks with Nmap, a network exploration and security scanning tool.