Censys

Search engine for Internet connected host and devices

API keyHTTPSNo CORSSecurity

Verified today: 100% uptime

Is Censys free, and does it need an API key?

A free Censys account can use the Platform API, but only its lookup endpoints: fetch a host, certificate or web property you already know. Search needs a paid plan, and the old API ID and secret no longer work for free users.

Price: Free tier, paid above it
API key: Required, free signup
Free limits: Lookup endpoints only: hosts, certificates and web properties.

How to get a Censys API key

Create a free Censys Platform account.
Generate a Personal Access Token in your account settings.
Send it as a Bearer token. Legacy Search API IDs and secrets are disabled for free users.

Send it as Authorization: Bearer YOUR_TOKEN

Checked by hand on 2026-10-24 against Censys: transition guide for free users and Censys: get started with the APIs. Providers change their terms, so confirm on their own pages before you commit.

API key

Required, free signup

HTTPS

Supported

Browser calls

No, needs a proxy

Status

Live · 100/100

Overview & Architectural Role

Censys provides programmatic access to search engine for internet connected host and devices. Delivered over secure HTTPS protocols, it exposes structured endpoints designed to integrate cleanly into modern frontend frameworks, backend microservices, and automated data pipelines without requiring local database provisioning.

Who it is built for

Engineers building web dashboards, mobile applications, CLI utilities, or background cron workers in need of reliable security data feeds.

Architectural Advantage

Consuming Censys removes the operational overhead of running custom scrapers, orchestrating headless browser fleets, or manually seeding and maintaining a local database. Instead of reverse-engineering volatile DOM layouts or dealing with anti-bot IP blocks, your application connects directly to a standardized JSON interface designed for backend ingestion with consistent schema schemas. Dedicated authentication ensures rate quotas and credential tracking per project environment.

What our checks found

Health score: 100/100
Reliability: 100%
Average latency: 2159ms

Last checked 2026-10-24. Measured independently, not self-reported by the provider.

Core Use Cases & Architecture Ideas

Practical real-world patterns for integrating Censys into software systems.

Automated SaaS Feature Integration

Embed data and functionality from Censys directly into application onboarding, profile enrichment, or reporting dashboards.

Architecture: Backend service worker fetches Censys during user workflows, caches responses in Redis, and hydrates UI state.

Scheduled Reporting & Monitoring Bot

Periodically extract updates from Censys to generate daily digests, analytics reports, or Slack notifications.

Architecture: A scheduled GitHub Action or cron worker executes a lightweight script calling Censys, formatting markdown summaries for stakeholders.

Rapid Prototyping & Hackathon Showcase

Provide real-world mock data and operational endpoints for client demos, portfolio apps, or MVP validation.

Architecture: Static client SPA queries Censys directly to populate mock dashboards, graphs, and interactive UI states without a custom backend.

Code Implementation Examples

Production-ready starting templates with error handling for Censys.

// Requires an API key. Check the docs for whether it goes in a header or a query parameter.
// Modern native fetch with error handling
async function callApi() {
  try {
    const response = await fetch('https://docs.censys.com/api/v1/resource', {
      method: 'GET',
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY',
      Accept: 'application/json',
    },
    });

    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }

    const data = await response.json();
    console.log('Response payload:', data);
    return data;
  } catch (error) {
    console.error('API request failed:', error);
    throw error;
  }
}

// callApi();

This API does not send CORS headers, so a browser will block a direct call from your front end. Call it from your server, or put a small proxy in front of it.

Response Payload & Live Testing

Inspect the expected JSON structure returned by Censys.

Expected JSON Response Payload

Authentic sample payload structure to evaluate schema attributes before integration.

{
  "status": 200,
  "api": "Censys",
  "endpoint": "/censys",
  "data": {
    "id": 101,
    "title": "Censys Sample Payload",
    "description": "Search engine for Internet connected host and devices",
    "verified": true,
    "category": "Security",
    "updated_at": "2026-10-24T07:39:06.853Z"
  },
  "meta": {
    "response_time_ms": 2159,
    "cached": false
  }
}

Format: application/json

Integration Considerations & Best Practices

Technical factors to keep in mind when integrating Censys into production environments.

Implement In-Memory or Edge Caching

Avoid triggering rate limits on public feeds by caching response payloads in Redis, Vercel KV, or standard HTTP Cache-Control headers with a 5-to-15 minute TTL.

Shield Credentials in Backend Route Handlers

Never expose private API keys in client-side JavaScript or bundle environments. Proxy requests through a Next.js API route or serverless backend to keep secret keys out of public DevTools inspection.

CORS Proxy Required for Browser Frontend Calls

This API does not send Access-Control-Allow-Origin response headers. Direct fetch() calls from browser JavaScript will fail due to Same-Origin Policy. Route your calls through a server backend or lightweight edge proxy.

Validate HTTP Status Before Parsing JSON

Always inspect response.ok before executing response.json(). Upstream services returning 4xx or 502 Bad Gateway often serve HTML error pages, which cause syntax errors when parsed as JSON.

Where this listing comes from

FishFish is an automated service designed to quickly detect and mitigate phishing threats before they can be exploited for malicious purposes. It provides a streamlined solution for identifying harmful resources efficiently.

No keyCORSHTTPS

Verified today: 100% uptime

View Details

Censys — common questions

Answered from what our own scheduled checks found, not from the provider's marketing.

Is the Censys API free?

Does Censys need an API key?

Yes, and it is free: you get one by signing up. Send it as Authorization: Bearer YOUR_TOKEN.

How do I get a Censys API key?

1. Create a free Censys Platform account. 2. Generate a Personal Access Token in your account settings. 3. Send it as a Bearer token. Legacy Search API IDs and secrets are disabled for free users.

What are the Censys API rate limits?

Lookup endpoints only: hosts, certificates and web properties.

Can I call Censys from browser JavaScript?

Not directly. Censys did not return CORS headers when we checked, so the browser will block your page from reading the response even though the request itself succeeds. Call it from a server, or put a small proxy in front of it.

Is Censys still working?

Yes, as of 2026-10-24. Our automated check reached Censys and recorded a 100% reliability score with a median response time of 2159 ms. We re-check on a schedule, and this page updates with the result.