usefulweb.appDependable little tools for people and AI agents. Developer & data tools

Developer & data tools

Deterministic helpers for developers, data and research. · 15 tools

  • HeaderLens

    Is a website down? Multi-region status, redirects, TLS and security headers.

    Uses live data · JSON API · MCP

  • Accessibility Snapshot

    Static WCAG 2.2 snapshot of a page: findings by severity, evidence and manual checks.

    Uses live data · JSON API · MCP

  • Browser Compatibility Checker

    Which browsers support a CSS property, JS API or HTML element? MDN data + Baseline status.

    Uses live data · JSON API · MCP

  • CiteShape

    Paste a DOI, ORCID iD, ISBN or arXiv ID: validated, resolved, and formatted as APA, BibTeX and RIS.

    Uses live data · JSON API · MCP

  • CyberChef-lite Pipeline

    One-click decoding recipes: JWT, base64 → gunzip → JSON, double URL decode, hex dump.

    JSON API · MCP

  • DataFresh

    Is this dataset or API still fresh? Newest record, update cadence check and schema drift.

    Uses live data · JSON API · MCP

  • FileFit

    Can this app open, edit or convert that file format? Verified facts with sources.

    JSON API · MCP

  • LocaleKit Country Format Rules

    Address form fields, postal-code regex, calling code and date formats for any country.

    JSON API · MCP

  • Network Speed Tester

    Measure latency, jitter, download and upload speed between your browser and our server.

    JSON API · MCP

  • RuleDate Deadline Calculator

    Business-day and deadline maths with public holidays and a step-by-step rule trace.

    JSON API · MCP

  • Safe Markdown Preview

    Render Markdown with GFM tables and footnotes to sanitised HTML and see what was removed.

    JSON API · MCP

  • TimeFair Meeting Planner

    Find fair meeting times across time zones, with DST-exact local times and rotation.

    JSON API · MCP

  • Unicode Inspector

    Every code point with name, script and bytes, plus hidden characters and look-alikes.

    JSON API · MCP

  • UnitProof Unit Calculator

    Unit maths you can audit: dimension check, exact factors and a full derivation tree.

    JSON API · MCP

  • Unix Permission Calculator

    chmod calculator: octal ↔ rwx, setuid/sticky, u+x style changes, umask and ls -l.

    JSON API · MCP

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