Is Have I Been Pwned safe to use?

Yes. It uses k-anonymity for password checks, so your password never leaves your device in full, and it is run by a well-regarded security researcher. It is the reference tool for a reason.

Can I check for breaches without an API key?

For email lookups on the HIBP website, yes. For automated or bulk checks through the API, HIBP requires a key. Some open-source tools bundle their own access or use keyless paste-search as a fallback.

What should I do if my email is in a breach?

Change that site password, change it anywhere you reused it, and turn on two-factor authentication. The breach itself you cannot undo; the reuse is what you control.

BreachesJune 16, 20266 min read

Free and Open-Source Have I Been Pwned Alternatives (2026)

By Scott Anderson, Clearfront maintainer

Have I Been Pwned is the reference for breach checking, but it is not the only option, and it is not always the right one. This is an honest comparison of the free and open-source tools for checking your breach exposure, plus how they actually work under the hood.

What are the best free Have I Been Pwned alternatives?

The strongest free options are Mozilla Monitor for a consumer-friendly breach check, DeHashed and LeakCheck for deeper lookups, Intelligence X for archived leak data, and self-hosted tools like Clearfront if you want to run the check on your own machine. Each fills a gap HIBP leaves.

HIBP is excellent and I use it. But it is one index, it rate-limits its API behind a key, and it only tells you the breach, not the rest of your exposure. Depending on what you need, another tool may fit better.

How do breach checkers work without seeing your password?

Good breach checkers use k-anonymity: your password is hashed, and only the first five characters of the hash are sent to the server, which returns every match for that prefix so the comparison happens on your side. The service never sees your actual password.

This matters because a breach checker that asks for your real password is a breach waiting to happen. HIBP pioneered the k-anonymity model for its Pwned Passwords range, and it is the standard any trustworthy tool should follow. If a site wants your plaintext password to check whether it leaked, close the tab.

The alternatives, and where each one fits

Mozilla Monitor

Free, backed by Mozilla, built on HIBP data with a friendlier interface and ongoing monitoring. The best pick for a non-technical person who just wants email alerts.

DeHashed and LeakCheck

Paid, but they index credential data and paste dumps that HIBP does not, including some plaintext. Useful for investigators who need to see what actually leaked, not just that a breach happened.

Intelligence X

An archive of leaks, pastes, and historical data. Strong when you need the record of an old breach that other indexes have dropped.

Clearfront

Open-source and self-hosted. It checks breach exposure through the HIBP API and cross-references public paste dumps, but it does the rest of the footprint sweep in the same run: which accounts your email is registered on, which usernames connect, what a broker knows. You run it locally with your own keys, so your email is not logged by a third party. The tools reference lists every source it uses.

Why breach data alone is not the full picture

A breach hit is a starting point, not a conclusion. The email in the breach is registered on other sites. The password in it was probably reused. The username attached to it maps elsewhere. Checking the breach and stopping there misses the chain that actually gets people compromised.

That is the case for running a full footprint scan instead of a single lookup. See how the passes connect in the self-OSINT walkthrough, or if you just leaked-checked yourself after the news, read how to check the 24 billion record dump.

Frequently asked questions

Is Have I Been Pwned safe to use?: Yes. It uses k-anonymity for password checks, so your password never leaves your device in full, and it is run by a well-regarded security researcher. It is the reference tool for a reason.
Can I check for breaches without an API key?: For email lookups on the HIBP website, yes. For automated or bulk checks through the API, HIBP requires a key. Some open-source tools bundle their own access or use keyless paste-search as a fallback.
What should I do if my email is in a breach?: Change that site password, change it anywhere you reused it, and turn on two-factor authentication. The breach itself you cannot undo; the reuse is what you control.

Scott Anderson believes your personal data is yours to own and protect. He built Clearfront, a free, open-source tool for scanning and scrubbing your own digital footprint from public data, and he writes about OSINT, breach exposure, and personal privacy.