About Trusted Sender Score
Trusted Sender Score is a free cyber email and domain security verification service built to help organizations defend against email spoofing, phishing scams, and other email-based threats.
What We Do
Trusted Sender Score gives domain owners, IT administrators, and security professionals a straightforward way to assess domain and email sender trustworthiness. By entering a host domain, users receive a trust evaluation that helps identify potential vulnerabilities before they can be exploited.
The service is a product of Zulu Labs Inc and is offered at no cost — part of a broader commitment to raising the bar on email security across the internet.
Why It Matters
Email spoofing and phishing attacks continue to be among the most common vectors for cyber threats. Without proper domain authentication, malicious actors can impersonate legitimate domains, damaging brand reputation and putting recipients at risk.
Trusted Sender Score addresses this by providing:
- Free domain trust verification — check any host domain's security posture
- Anti-spoofing protection — identify gaps that leave domains vulnerable to impersonation
- DMARC tools and guidance — resources to help implement email authentication standards
The Bigger Picture
Trusted Sender Score is part of a wider ecosystem. The companion Trusted Sender Network app bundles email and cyber security tools into a single free application, while the Cyber Security API enables developers to integrate domain trust data into their own workflows.
Together, these tools help organizations move from reactive threat response to proactive email security management.
Explore More
Ready to dive deeper? Learn how the scoring works on our Metrics page, follow step-by-step guidance on How To Use the tool, or visit the FAQ for answers to common questions.