Building a Privacy-First URL Shortener on Blockchain

Source: Dev.to

Why Traditional URL Shorteners Are a Privacy Nightmare

• When you click a bit.ly link, the service logs your IP, timestamp, and user agent.
• It sees the destination URL.
• It can track your browsing patterns.
• It may sell this data to advertisers.
• Even if you trust the shortener, its database can be hacked.

Solution: cryptly – a Privacy‑First URL Shortener

I built cryptly to solve this problem using blockchain and encryption.

Encryption (Client‑Side)

const encrypted = await crypto.subtle.encrypt(
  { name: "AES-GCM", iv: iv },
  key,
  urlBuffer
);

Blockchain Storage

• Encrypted URL stored on the Cronos blockchain.
• Immutable and decentralized.
• No centralized database to hack.

Decryption (Browser)

• Browser fetches the encrypted payload from the blockchain.
• Decrypts locally using the Web Crypto API.
• The server never sees the destination URL.

Tech Stack

• Cloudflare Workers – serverless, edge deployment.
• Web Crypto API – native browser encryption.
• Cronos blockchain – decentralized storage.

Privacy Benefits

• ✅ Server never sees destination URLs.
• ✅ No tracking, no analytics.
• ✅ No database to leak.
• ✅ Censorship‑resistant (blockchain).

Live Demo & Source

• Demo:
• Source:

Still in early stages but feedback is welcome!

privacy #blockchain #webdev #opensource