The Censys alternative for researcher-friendly internet intelligence
Internet-wide host, certificate and DNS intelligence in one engine - with perceptual favicon search, an MCP server and a free researcher tier.
Profundis is a unified internet-intelligence search engine. Like Censys, it indexes internet-wide assets - hosts, services and TLS certificates - for attack-surface and security research.
Profundis brings these datasets together with live and historical DNS, WHOIS and virtual hosts under one field:value syntax, then adds perceptual favicon similarity and an official MCP server. It is operated from the EU and offers a researcher-friendly free tier with anonymous host/DNS previews.
What Censys is known for
Censys is widely known for certificate-centric internet scanning and attack-surface management.
Why Profundis
A unified internet-intelligence engine - exposed hosts and services, DNS (live + historical/passive), WHOIS (with reverse/registrant lookups), TLS certificates and virtual hosts - all searchable in one place with a field:value syntax (wildcards, AND/OR/NOT).
Favicon perceptual-similarity search (MMH3 + visual similarity) that finds visually similar favicons, not just exact icon-hash matches - Profundis’s signature differentiator.
A free tier with no signup required for the hosts and DNS anonymous preview, plus transparent credit-based pricing from Free and Solo to Professional and Enterprise.
An official MCP (Model Context Protocol) server, so AI agents like Claude can call Profundis search as native tools - AI-agent-native distribution.
EU-based operation (Perspective Analytics SAS, France) for a data-residency / GDPR-friendly posture.
Profundis vs Censys
| Capability | Profundis | Censys |
|---|---|---|
| Internet-wide host & service data | Core feature | Core feature |
| TLS certificate search | Built in | Core feature |
| Unified DNS (live + historical/passive) | Built in | Supported |
| WHOIS + reverse/registrant lookups | Built in | Varies by plan |
| Field:value query syntax (wildcards, AND/OR/NOT) | Across all datasets | Supported |
| Favicon perceptual similarity | Visual similarity | - |
| Official MCP server for AI agents | Native tools | - |
| Free tier with no-signup host/DNS preview | No signup to preview | Varies by plan |
| OSINT tools suite (typosquat, subdomains, registrant…) | Included | Varies by plan |
| EU-based operator (GDPR posture) | France (EU) | Varies |
“✓” marks a Profundis capability. “-” means the capability is not a documented public feature of Censys at the time of writing - not a definitive statement about its roadmap. Based on publicly available information.
Frequently asked questions
Profundis has a free tier and an anonymous host/DNS preview that needs no signup, which makes it approachable for individual researchers. Higher quotas, the API and advanced tools are available on transparent credit-based paid plans.
Both index internet-wide hosts and TLS certificates. Profundis unifies that with live and historical DNS, WHOIS with reverse/registrant lookups and virtual hosts in one query language, and adds perceptual favicon similarity to discover related and lookalike infrastructure.
Yes. TLS certificate data is one of the datasets Profundis unifies alongside hosts, DNS, WHOIS and virtual hosts, all searchable with the same field:value syntax.
Yes. Profundis exposes an API and an official MCP server, letting AI agents like Claude run Profundis searches as native tools.
Profundis is operated by Perspective Analytics SAS in France (EU), giving it a data-residency and GDPR-friendly posture.
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