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The LeakCheck API lets you check whether an identifier — an email address, username, phone number, domain or password hash — appears in known data breaches and info-stealer logs. There are two APIs:
  • Pro API v2 — authenticated with an API key. Returns full breach records (including passwords and all leaked fields), supports every search type and pagination. Available on paid plans.
  • Public API — no authentication required. Returns only the list of breach sources and the categories of exposed data, never the data itself. Free, including commercial use.

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Pro API vs Public API

Pro API v2Public API
Search by e-mail, username✅✅
Sources display✅✅
Passwords display✅❌
Full data exposure✅❌
Allowed RPS3 (upgradeable)1
Search by password, domain name✅ (from Enterprise)❌
Pricingfrom $9.99/mofree

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Base URLs

Pro API v2:  https://leakcheck.io/api/v2
Public API:  https://leakcheck.io/api/public

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Quick start

curl "https://leakcheck.io/api/v2/query/example@example.com" \
  -H "Accept: application/json" \
  -H "X-API-Key: $LEAKCHECK_APIKEY"

Pro API v2 lookup

The main query endpoint: request, response and pagination.

Search types

Everything you can search by, from emails to info-stealer origins.

Public API

Free breach-source lookups without an API key.

Python wrapper & CLI

Official leakcheck package on PyPI, with a CLI tool included.

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Commercial usage

You are free to use the Public API for commercial purposes — the only requirement is a “Powered by LeakCheck” link on your website (see Public API terms). If you wish to use the Pro API commercially, please contact our support team at the@leakcheck.net and describe your project.