Free Cyber Email & Domain Security
Verification You Can Trust
Enter a host domain to check its trusted sender score and protect against SPOOF email phishing scams. Newly registered domains may take up to 24 hours to propagate before appearing in results.
Check Your Domain Now
Trusted Sender Network
- Cyber security tools bundled into one free app
- DKIM wizard for email authentication setup
- Developer tools and API access
- Multiple-domain trust checker with upload support
- Email reputation visibility and accountability
- DMARC compliance research integration
- Trusted sender scores for email service providers
- Sign in / sign up for user accounts



DMARC Email Security
- Ultimate DMARC project guide with complete implementation steps
- Anti-spoof conformance fact sheets for compliance
- Email authentication and anti-spoofing best practices
- DMARC email reputation sales and marketing tips
- Email deliverability improvement strategies
- DMARC compliance research resources



Cyber Security API
- Programmatic access to domain trust verification
- API documentation available on Postman
- Integrate trusted sender scoring into your workflows
- Support for bulk domain checks
- RESTful API design for easy integration
- Free access for developers and security teams


Security in Action
About Trusted Sender Score
Trusted Sender Score is a free cyber email and domain security verification service by Zulu Labs Inc. It helps organizations and domain owners protect against email spoofing, phishing scams, and other email-based threats through domain trust checking and DMARC tools.
The companion app, Trusted Sender Network, bundles email and cyber security tools into one free application — including a DKIM wizard, developer tools, and a Cyber Security API.
Trusted Sender Score provides a practical, accessible way for individuals and organizations to verify the legitimacy of email senders and domain identities before engaging with incoming messages. By entering a host domain into the free checker, users gain immediate insight into a sender's standing within the broader email ecosystem. This verification layer is especially valuable in an era where spoofed addresses and impersonation attempts have become increasingly sophisticated. The service empowers everyday email users to make informed decisions about which messages deserve their attention and which should be treated with caution, effectively turning domain security into a straightforward, user-friendly process rather than a complex technical undertaking.
The fight against phishing relies on visibility, and Trusted Sender Score delivers exactly that by revealing the reputation and trust signals associated with any given domain. When a sender's identity can be checked quickly and reliably, the advantage shifts to the recipient. Cybercriminals depend on confusion and haste, hoping that targets will click before they think. A quick verification step disrupts that strategy at its core. The platform is designed to be fast enough to fit naturally into everyday workflows, so checking a domain before responding to an unexpected email becomes a habit rather than a chore, strengthening overall cyber hygiene one verification at a time.
Newly registered domains present a unique challenge in the trust landscape, as they may not yet appear in verification results until propagation completes. This brief window is precisely when malicious actors often strike, registering domains to launch campaigns before reputation systems catch up. Trusted Sender Score accounts for this reality, advising users to be especially cautious with very recent registrations while also providing a mechanism to check once propagation has settled. Understanding this timing nuance helps users interpret results correctly, avoiding both false confidence in unknown senders and unnecessary suspicion of legitimate new businesses establishing their email presence for the first time.
Beyond simple sender checks, the platform bundles a comprehensive set of security tools into a single free application, removing the friction of juggling multiple services. From DKIM wizard assistance that guides users through email authentication setup to multi-domain trust checking with upload support, the toolkit addresses the full spectrum of email security needs. This consolidated approach means that even those without dedicated IT teams can implement meaningful protections. Each tool is designed with the same clean, intuitive interface, so moving between functions feels natural and consistent, reducing the learning curve and encouraging regular use of the security features available.
Email reputation visibility plays a central role in the platform's mission, giving senders and receivers alike a clearer picture of how domains are perceived across the internet. For legitimate organizations, understanding their own sender score allows them to identify and correct issues that might be causing messages to land in spam folders or be flagged by recipients. For those receiving messages, the same data provides context for evaluating unfamiliar senders. This two-way transparency fosters a healthier email environment where accountability is the norm and good practices are rewarded with better deliverability and stronger trust relationships across the network.
Developer tools and API access extend the value of Trusted Sender Score beyond the web interface, enabling technical teams to integrate domain verification directly into their own applications and workflows. This programmatic approach allows businesses to build security checks into their existing systems, whether that means validating sender domains before processing form submissions, screening inbound messages, or automating trust assessments at scale. The availability of these resources underscores the platform's commitment to serving both casual users and sophisticated developers, ensuring that the underlying security intelligence can be leveraged wherever it is needed most.
DMARC compliance research and integration round out the platform's protective capabilities, helping organizations understand and implement the authentication standards that underpin trustworthy email delivery. By connecting sender score data with DMARC insights, users gain a more complete picture of how their domains are being used and whether unauthorized parties are attempting to send mail under their identity. This alignment between verification and compliance supports a proactive security posture, where organizations move beyond merely reacting to threats and instead establish the structural safeguards that prevent abuse in the first place.
At its core, Trusted Sender Score is about restoring confidence in an essential communication channel that has been steadily eroded by spoofing and phishing. Email remains one of the most important tools for business and personal communication, yet its openness makes it vulnerable to exploitation. By providing free, accessible verification that anyone can use, the platform democratizes security in a way that benefits the entire ecosystem. Whether checking a single domain or managing trust across many, users gain the clarity needed to navigate their inboxes with greater assurance, making every interaction safer and every decision more informed.
Domain Administration
Domain Admin
Manage Your Domain Verification
Learn how to become a domain administrator for Trusted Sender Score and manage your domain verification settings. The process gives you control over how your domain's trusted sender score is presented and maintained.
Zulu EDM Settings
Email Domain Management
Configure Zulu EDM settings for your domain to ensure proper email authentication and alignment with DMARC policies. Essential for organizations serious about email security.
Resources
Research Sitemap
Explore the cyber-security research sitemap for in-depth resources on DMARC compliance, email reputation, and domain trust scoring methodologies.
Media Releases
Stay informed with the latest media releases and updates from Trusted Sender Score and Zulu Labs Inc regarding email security developments.
Resources Lightbox
Access a curated collection of guides, fact sheets, and tools through the resources lightbox — your quick reference for email and domain security.
Multi-Language Support
Trusted Sender Score supports English and Spanish, making domain security verification accessible to a broader audience.