OverPhish: Phishing Domain Blocker

OverPhish: Phishing & Malware Domain Blocker

Stop phishing before it stops you. OverPhish is a lightweight, privacy-first browser extension that blocks access to known phishing and malware domains in real time — all processing happens locally in your browser.

Key Features

• Instant Protection — Uses a fast Bloom filter + reversed suffix Trie for sub-millisecond domain checks. Blocks malicious sites before they load.
• Daily Updated Blocklist — Automatically merges high-quality public sources (OpenPhish, PhishTank, URLHaus, Hagezi TIF, Jarelllama Scam Blocklist) every 24 hours.
• 100% Private & Local — Zero telemetry, no accounts, no data collection. The only network request is the daily download of a public, plain-text blocklist from overphish.io/blocklist.txt. Nothing about your browsing ever leaves your device.
• User-Friendly Controls — Clear block page with "Allow Once" (temporary bypass) and permanent whitelist options. Built-in permanent whitelist for major providers (Google, Microsoft, Apple, etc.) to avoid breaking legitimate sites.
• Lightweight & Efficient — Under 300KB install size. No performance impact, even on lower-end devices.
• Transparency & Audit-Friendly — The full source code is publicly available on GitHub for independent verification and security auditing (redistribution prohibited). See the repository for details.

How It Works OverPhish intercepts navigation requests and checks domains against a local index built from the latest blocklist. If a match is found, it blocks the request and shows a warning page — preventing phishing pages from loading.

Privacy First OverPhish collects absolutely nothing. No tracking pixels, no analytics, no user data transmission. All threat detection runs entirely offline after the initial blocklist fetch. Full Privacy Policy.

Supported Browsers

• Now available on Firefox!
• Also on Chrome Web Store
• Edge and other Chromium-based browsers via the Chrome store

Important Notes

• This extension uses Manifest V3 with declarativeNetRequest for efficient blocking.
• Source code is published solely for transparency and auditing — redistribution or republishing is strictly prohibited.
• Official downloads only from trusted stores. Never install from unofficial sources.

Help keep the web safer — install OverPhish today!

Questions or security reports? Visit overphish.app or the GitHub repo.