SecLens.ONE
Free, open-source score of a domain's public email security across seven protocols, with the DNS fixes
ToolEmail SecurityCloud, Self-hosted, Open source
Pricing: Free, with no account required.
Reviewed by the Cyber Vendor Guide editorial team against the public sources cited below · Last reviewed September 2026 · How we review listings
What is SecLens.ONE?
SecLens.ONE is a free, open-source check of a domain's public email security, made by 42Sec PTE. LTD. in Singapore. It reads the domain's DNS and scores seven protocols (SPF, DMARC, DKIM, DNSSEC, MTA-STS, DANE and TLS-RPT) out of 100, giving more points for enforced policies than for records that are only published. Domains that declare they send no mail with a Null MX record are scored on a separate profile, so they are not marked down for missing mail infrastructure. Each assessment comes with the DNS records and MTA-STS policy file to publish and a staged plan for moving DMARC to enforcement, downloadable as one file. The scoring rules are published, and the same assessor is available on GitHub as an Apache-2.0 command-line tool written in Go that can check domains in bulk and output JSON. 42Sec benchmarks scores against its own July 2026 study of the Cloudflare Radar top one million domains, and says AI agents can run the check through an MCP server. No account is needed. Assessed domains appear in a public list of recent checks unless the private option is ticked.
Best for: Anyone who wants an outside view of how hard a domain is to spoof, and the DNS changes that would fix it
Key Features
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Sources & references
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Key facts
- Pricing
- Free, with no account required.
- Model
- Free
- Cloud
- Yes
- Self-hosted
- Yes
- Open source
- Yes