# Show HN: LinkPreview.io - Debug social cards across 6 platforms (no signup)

I built a tool that shows how your URL looks when shared on Twitter, Facebook, LinkedIn, Slack, Discord, and Google Search. All in one view, no login required.

Try it: https://linkpreview.io

## The Problem

Debugging broken social share cards currently requires jumping between 5+ platform tools (Facebook Debugger, Twitter Card Validator, LinkedIn Post Inspector), each requiring authentication. I wanted one place to paste a URL and see everything.

## What's Different

Most tools just show raw meta tag data. This renders actual preview cards and scores your tags 0-100 with actionable fixes.

- Both card variants (Twitter/Facebook each have large + compact layouts) - Truncation visualization (shows exactly where titles get cut on each platform) - Scored recommendations (20+ checks with copy-paste code snippets) - Zero friction (no signup, <2 second results)

## Tech Stack

SvelteKit (Svelte 5), Cloudflare Pages, Cheerio for server-side parsing. Client bundle <30KB gzipped.

The hard part was SSRF protection. The API fetches user-provided URLs, so I had to block private IPs, cloud metadata endpoints (169.254.169.254), and check every redirect hop to prevent attackers from using my server to port-scan internal networks.

## What I Learned

Open Graph is inconsistent across platforms. Twitter falls back to og:title sometimes. Facebook requires og:type, LinkedIn doesn't. Google ignores Open Graph entirely. Character limits vary wildly and are undocumented.

## Future

Phase 2: bulk CSV upload, scheduled monitoring, API access, Chrome extension.

Built over a weekend. Feedback welcome.

SvelteKit, Tailwind v4, Cloudflare Pages

Show HN: Linkpreview.io – Debug and preview social share cards