Censys

API

Search engine for internet-connected hosts and devices (security intelligence)

Overview

Censys API provides programmatic access to its search engine for internet-connected hosts, certificates, and domains. Key endpoints include /v2/hosts/search (query hosts by IP/domain), /v2/certificates/search (certificate metadata), and /v2/domains/search (domain records). Responses are in JSON format. Use cases include security teams discovering exposed assets, researchers identifying vulnerable devices, threat analysts tracking threat actors' infrastructure, and compliance teams auditing public-facing systems. It supports filtering by attributes like open ports, software versions, or certificate details to refine searches.

Example Integration (JavaScript)

script.js JS


fetch('https://search.censys.io/api')
  .then(res => res.json())
  .then(data => console.log(data))
  .catch(err => console.error(err));

Key Features

RESTful API
JSON response format
Host/certificate/domain search endpoints
Advanced filtering capabilities
API key authentication

Frequently Asked Questions

? Is Censys free to use?

Yes, Censys offers a free tier with limited monthly queries; paid plans are available for higher volume and advanced features.

? Does it require an API Key?

Yes, authentication via API key is mandatory for all API requests. Keys can be obtained from the Censys account dashboard.

? What is the response format?

All API responses are in JSON format, containing structured data about hosts, certificates, or domains based on the query.

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Tool Info

Pricing Freemium

Category Security

Platform Public API

Pros

⊕ Comprehensive internet asset data
⊕ Detailed metadata (ports, software, certificates)
⊕ Supports advanced query filtering
⊕ Integrates with security workflows

Cons

⊖ Rate-limited free tier
⊖ Paid plans needed for high-volume access
⊖ Steep learning curve for advanced queries
⊖ Occasional data staleness