Password Utilities

Is Common Password

Validates passwords against common password databases to prevent weak credential selection. Access via MCP in Cursor/Windsurf or REST at `/v1/password/is-common`. Returns boolean indicating if password appears in breach lists like rockyou.txt. Essential for registration flows and security audits where deterministic password strength validation matters.

API Endpoint

GET /v1/password/is-common

Code Examples

curl "https://tinyfn.io/v1/password/is-common" \
  -H "X-API-Key: YOUR_API_KEY"

const response = await fetch('https://tinyfn.io/v1/password/is-common', {
  headers: { 'X-API-Key': 'YOUR_API_KEY' }
});
const data = await response.json();
console.log(data);

import requests

response = requests.get('https://tinyfn.io/v1/password/is-common',
    headers={'X-API-Key': 'YOUR_API_KEY'})
data = response.json()
print(data)

Use via MCP

Add to your AI agent

Connect your AI agent (Claude, Cursor, Windsurf, etc.) to TinyFn's password tools:

{
  "mcpServers": {
    "tinyfn-password": {
      "url": "https://tinyfn.io/mcp/password",
      "headers": {
        "X-API-Key": "YOUR_API_KEY"
      }
    }
  }
}

Learn more about MCP setup →

Related Tools

FAQ

How do I check if a password is commonly used in MCP tools?

Call the is-common-password tool with your password string. It returns true/false based on known breach databases and common password lists.

What password databases does this tool check against?

Checks against curated lists including rockyou.txt, have-i-been-pwned compilations, and other security research datasets containing millions of compromised passwords.

Does this tool store or log the passwords I check?

No, passwords are processed ephemerally for comparison only. The tool performs deterministic lookups without storing input data.

Can I integrate this into user registration workflows?

Yes, perfect for real-time password validation. Use the REST endpoint in forms or the MCP tool in AI-powered registration assistants.

What's the difference between this and basic password complexity rules?

Complexity rules check patterns (length, characters) while this checks actual breach history. A 12-character password can still be common if it's 'Password123!'.

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