Censys API

API

Search engine API for Internet-connected hosts and devices

Overview

The Censys API provides programmatic access to its search engine for Internet-connected assets like hosts, certificates, and autonomous systems. Key endpoints include /v2/hosts/search (IPv4/domain queries), /v2/certificates/search (SSL/TLS certs), and /v2/asns/search (ASN data). Responses are JSON-formatted, containing details such as open ports, protocols, software versions, and certificate metadata. Use cases include security research, vulnerability assessment, threat intelligence gathering (e.g., tracking exposed services), and compliance monitoring for sensitive infrastructure.

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
JSON Response Format
Host/Certificate/ASN Search
Advanced Filtering
Historical Data (Paid)
Pagination Support

Frequently Asked Questions

? Is the Censys API free to use?

Yes, it offers a free tier with limited requests; paid tiers unlock higher limits and historical data access.

? Does it require an API Key?

Yes, all requests need authentication via an API key obtained from the Censys account dashboard.

? What is the response format?

The API primarily returns structured data in JSON format for all endpoints.

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Tool Info

Pricing Freemium

Category Security

Platform Public API

Pros

⊕ Comprehensive Asset Coverage
⊕ Detailed Metadata
⊕ Threat Intelligence Utility
⊕ Well-Documented
⊕ Automation Capabilities

Cons

⊖ Free Tier Rate Limits
⊖ Paid Access for Full Features
⊖ Complex Query Syntax
⊖ No Free SLA
⊖ Requires API Key