# Censys vs Shodan

> Censys scores 64.1 (B) to Shodan's 39.5 (E) for secintel exposure. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/censys-vs-shodan
- Markdown: https://www.anchorterminal.com/compare/censys-vs-shodan.md (~5,100 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-03

Censys scores 64.1 (B) on agent readiness against Shodan's 39.5 (E), and leads in 6 of 7 scored categories. Shodan leads on payments & pricing. Both do secintel exposure.

- Censys: grade B, 64.1/100, rank #420 of 1349. Markdown https://www.anchorterminal.com/tools/censys.md · JSON https://www.anchorterminal.com/api/v1/tools/censys.json
- Shodan: grade E, 39.5/100, rank #1221 of 1349. Markdown https://www.anchorterminal.com/tools/shodan.md · JSON https://www.anchorterminal.com/api/v1/tools/shodan.json
- Best threat and security intelligence APIs for AI agents: https://www.anchorterminal.com/best/security-intelligence/index.md
- All 33 security intel comparisons: https://www.anchorterminal.com/compare/security-intelligence/index.md

## Which one, for what

### Censys (B)

Good for: An agent that needs to know what a host, web property or certificate exposes right now and how that changed, with DNS resolution and enrichment on paid plans.

Ahead on:
- Reliability, 55 against 40
- Schema & documentation, 82 against 46
- Agent ergonomics, 79 against 64
- Security & auth, 55 against 19
- Maintenance & community, 84 against 16
- Transparency & trust, 64 against 44

Watch for: Status feed records a networking outage of about 13 hours on 30 September 2026, periodic query failures from 20 to 22 September and failing searches on 2 November

### Shodan (E)

Good for: An agent that needs to know what is exposed on an IP or a range, which ports, products and CVEs, and to watch a network for change.

Ahead on:
- Payments & pricing, 40 against 35

Watch for: The API key is sent only as `key=` in the query string, with no scopes, no read-only key and no header option documented


## Why the edge

### Maintenance & community: Censys +68

- Censys (84): Newest changelog entry 2 November 2026 and censys-platform 0.16.7 on 29 October (30). Ten dated changelog entries between 8 September and 2 November and eight PyPI releases since 4 August (20). A closed service with a weekly changelog, a Gainsight community forum with Platform Q and A sections, an in-app feedback portal and support@censys.com. GitHub issue replies weren't read (12 of 15). Official SDKs in three languages regenerated from the spec, the Go and TypeScript repositories pushed on 3 November and PyPI on 29 October (15). The SDKs are 0.x and generated, with a stated grace period for dropping Python versions. CI wasn't read (7 of 10). 30 + 20 + 12 + 15 + 7 = 84.
- Shodan (16): No dated API change found. The blog's newest post is 7 August 2024, and the official Python library `shodan` 1.31.0 was published on 17 December 2023 with the repository's last push on 5 August 2024 (0 of 30). No releases or dated changelog entries in the last 90 days (0 of 20). 63 open issues on the Python repository with no push since August 2024; a support email and a help centre exist (5 of 25). The official Python SDK still installs but is two years old, and the other clients are community work (8 of 15). The repository has no CI configuration and no CHANGELOG entry since 1.28.0 of July 2022 (3 of 10). 0 + 0 + 5 + 8 + 3 = 16.

### Schema & documentation: Censys +36

- Censys (82): OpenAPI 3.1.0, titled Censys Platform API, version 1.0.161, served inside each reference page and the source of the three Speakeasy SDKs. No standalone download was found, and the censys-sdk-openapi repository holds only a README (22 of 25). llms.txt at docs.censys.com with a Markdown twin of every page (10). Endpoint descriptions state purpose and a use case ('Run a search query across Censys data', a SOC hunting for a C2 banner, JARM or favicon hash), MCP tools say what each does, with little on when not to use a call (14 of 20). Typed path, query and body fields, `page_size` default and maximum 100, required `query`, an Accept header for schema versions. The query itself is a CenQL string with its own language docs (11 of 15). Code samples in shell, Python, Go, JavaScript and Java, a status code table and problem+json ErrorModel bodies, but the search operation's usage example block is empty and 429 isn't among its responses (10 of 15). Versioned paths and Accept header, a dated changelog every week from 8 September to 2 November 2026 (15). 22 + 10 + 14 + 11 + 10 + 15 = 82.
- Shodan (46): The surface graded is the REST API at api.shodan.io. An OpenAPI 3.0.0 document at developer.shodan.io/api/openapi.json covers 37 paths and 44 operations, but declares no securitySchemes, no enums and a non-200 response on one operation only (15 of 25). No llms.txt on developer.shodan.io or www.shodan.io, both 404, and no Markdown docs served for agents (0 of 10). Every operation carries a description, and the reference says which calls cost credits and which plans can scan, with little on when not to use a call (12 of 20). Required flags on the key and path parameters, with `facets`, `query` and `fields` as free strings and no enums or constraints (7 of 15). Example requests and responses for every endpoint in the reference, and errors documented only as a non-200 status with an `error` field (9 of 15). No version in the path, the OpenAPI document says 1.0.0, and the only dated record of changes is the blog, whose newest post is 7 August 2024 (3 of 15). 15 + 0 + 12 + 7 + 9 + 3 = 46.

### Security & auth: Censys +36

- Censys (55): Personal access tokens as a Bearer header, several per user, named, shown once and deletable, with no scopes or expiry stated. Service accounts on Search and Core plans use OAuth 2 client credentials with module roles and a rotatable secret, and the MCP server takes OAuth with a consent page. Only the organisation id, not a secret, may travel in the query string (26 of 30). Module roles (Analyst, Manager), an API Access role and the advice to grant service accounts only the roles they need, but no read-only token and no confirmation step for deleting a collection (12 of 20). Results carry banners, HTML titles and certificate subjects from scanned hosts, and no guidance on treating them as untrusted was found in the API, MCP or skills docs (3 of 15). A platform audit log for admins that records service account activity, credit usage per member through the API and `X-Request-ID` on every response, with no documented per-call log for token holders (10 of 15). security@censys.com on the contact page. security.txt 404, no bug bounty, and the compliance page says Censys helps customers with SOC 2, ISO 27001 and FedRAMP without claiming any for itself (4 of 20). 26 + 12 + 3 + 10 + 4 = 55.
- Shodan (19): One key per account with no scopes, sent as `key=` in the query string on every documented call and in the OpenAPI document, with no header option. Read as a plain key, the way the Alpha Vantage listing was read, less 10 for the query string (10 of 30). No read-only key or least-privilege mode; the free plan's limits are quotas, not scopes, and alerts, notifiers and org members can be deleted with the same key and no confirmation (3 of 20). Results carry banners, HTTP titles and page bodies collected from arbitrary hosts, and no guidance on treating them as untrusted was found (3 of 15). `/api-info` reports the plan and credits, and no call log for the key holder was found (3 of 15). security.txt returns 404 on www.shodan.io, and no bug bounty, disclosure policy, SOC 2 or ISO 27001 was found on the pages read (0 of 20). 10 + 3 + 3 + 3 + 0 = 19.

### Transparency & trust: Censys +20

- Censys (64): A closed service under terms effective 1 October 2018 that are clear on who may use the data for what, with MIT SDKs and an Apache-2.0 CLI (15 of 30). Privacy policy of 1 April 2025 keeps data 'for as long as necessary' with no periods, while the retention policy revised 11 July 2023 gives seven days for queries before anonymisation and up to three years for ASM seed data after an account expires, and still names the retired Censys Search. Two GDPR representatives are named. No public DPA found, and the privacy page's mailto points to censys.io while its text says censys.com (16 of 30). The transition guide gives the Legacy Search API no sunset date, the Accept header allows schema versions but no lifecycle is published, and credit packs were discontinued on 2 November with no notice period stated (5 of 20). Hosted in the United States, Stripe and Google named, unnamed analytics, advertising and session replay vendors, no subprocessor list (8 of 20). 15 + 16 + 5 + 8 = 44.
- Shodan (44): Editorial half. A closed service whose terms at static.shodan.io/legal/terms.html were not read, because that host answers 403 to robots.txt, so their clarity can't be assessed; the Python library is MIT (5 of 30). The privacy policy at account.shodan.io/privacy carries no date, names no legal entity, retention period, data location or subprocessor, and says Shodan may share information with advertisers, business partners, sponsors and other third parties (5 of 30). The help centre says export credits are deprecated and no longer sold, with no date; no deprecation policy found (3 of 20). No subprocessors or data locations disclosed (0 of 20). 5 + 5 + 3 + 0 = 13.

### Reliability: Censys +15

- Censys (55): Graded as a hosted service on the Platform API. Atlassian Statuspage at status.censys.com with Platform API, Authentication, Credit Management and three MCP server components (20). Its feed lists 12 entries from 24 August to 2 November 2026. Two were maintenance on ASM. The rest include intermittent 500s on the Platform from 13:52 on 24 August to 09:52 the next day, periodic query failures from 20 to 22 September, historical data calls timing out for about an hour on 18 September, an internal networking outage of the Platform and ASM from 00:35 to 13:46 EDT on 30 September, and failing searches from 14:26 EST on 2 November still in monitoring at 19:08. One full outage of about 13 hours and two multi-hour periods of failing core queries, read as more than one major (5). Limits are published with numbers, concurrency 1 or 25 per organisation and 25 requests a second per IP with a burst of 125 (15). Overruns return 429 or 503, but no Retry-After, backoff guidance or idempotency keys were found, and the SDKs say only that they follow the API's default retry strategy (5 of 15). No SLA found. The terms disclaim any warranty that the service will meet requirements, and the pricing page names none (0). The v3 API is generally available (10). 20 + 5 + 15 + 5 + 0 + 10 = 55.
- Shodan (40): Read with the hosted lines. A public status page exists at status.shodan.io (UptimeRobot), but on 3 November 2026 its component list failed to load and it showed only that there were no updates in the last 7 days, so no component history was readable (10 of 20). No readable incident record for the 90 days (5). The billing page states that all API plans are limited to 1 request a second, and credits per plan are published with numbers (15). No 429, Retry-After or backoff guidance was found in the reference or the OpenAPI document; the only error statement is that a non-200 status carries an error message, and no idempotency keys exist for alert, notifier or scan writes. The official Python client throttles itself to 1 request a second and retries a timed-out search cursor, which is client behaviour, not an API contract (0). No SLA found on the billing, enterprise or developer pages (0). The REST API is generally available (10). 10 + 5 + 15 + 0 + 0 + 10 = 40.

### Agent ergonomics: Censys +15

- Censys (79): `fields` limits a search response to named fields and `page_size` caps it at 100, with raw and full variants of lookups chosen by endpoint (22 of 25). `page_token` with `next_page_token` and `previous_page_token`, `total_hits`, aggregate endpoints and a bulk lookup (20). A status code table that separates 401, 403, 422, 429 and 503, problem+json bodies and `X-Request-ID` on responses, but no catalogue of error codes beyond status (14 of 20). Lookups and search are safe to retry, but collections, tags, comments and member endpoints write with no idempotency key, and no tool annotations are documented for the MCP server (8 of 20). One required field on search, SDKs in Python, Go and TypeScript, a CLI and Claude Code skills, though every paid-tier call also needs the organisation id (15). 22 + 20 + 14 + 8 + 15 = 79.
- Shodan (64): `minify` on host lookups drops banners and returns ports and host facts, `minify` on search (on by default) truncates large fields and `fields` selects which fields come back, so an agent can size a response (20 of 25). `page` with 100 results a page, `facets` for summaries, `count` for a free total, and the whole filter language of the search engine (18 of 20). Errors are a non-200 status and a short message such as Invalid IP, with no code list to branch on (8 of 20). Most calls are GET reads. Alerts, notifiers, scans and org members are written with POST, PUT and DELETE and no idempotency key, and nothing marks a destructive call (10 of 20). Few required parameters and sensible defaults, but only one official SDK, the Python library, with the other twelve languages community work (8 of 15). 20 + 18 + 8 + 10 + 8 = 64.

## Score by category

| Category | Weight | Censys | Shodan | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 40 | Censys +15 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 82 | 46 | Censys +36 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 64 | Censys +15 |
| Security & auth | 14% (17.5 this run) | 55 | 19 | Censys +36 |
| Payments & pricing | 10% (12.5 this run) | 35 | 40 | Shodan +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 16 | Censys +68 |
| Transparency & trust | 7% (8.8 this run) | 64 | 44 | Censys +20 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **64.1 · B** | **39.5 · E** | |

## Facts side by side

| Fact | Censys | Shodan |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Censys, Inc. | Shodan |
| Hosted endpoint | `https://api.platform.censys.io/v3/` | `https://api.shodan.io` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Censys's Terms of Service. The Platform SDKs are MIT and the cencli command line tool is Apache-2.0 | Proprietary service. The official Python library and CLI in achillean/shodan-python are MIT |
| Tools exposed | 12 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-11-02 | 2023-12-17 |
| Terms last updated | no date given | no date given |
| Privacy policy last updated | no date given | no date given |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 11 stars | 3.5k stars |

## Verdicts

**Censys.** A versioned OpenAPI surface with field selection, page tokens, three official SDKs, a hosted MCP server and a free key of 100 credits a month. Paid enterprise access is sold by sales, scan results carry untrusted banner text with no injection guidance, and the status feed records a 13-hour outage on 30 September 2026.

**Shodan.** One GET endpoint per job returns ports, banners and vulnerabilities for an IP, with `minify` and `fields` to trim responses and public plan prices from a $49 one-time Membership. The key travels only in the query string with no scopes, 429 handling is undocumented, the terms were unreadable and the official library's last release was December 2023.

## Before you call either

### Censys

1. Send `X-Organization-ID` on every call. Without it the request runs with Free permissions and 403s on search, aggregate and collections
2. Budget one credit per action and per extra page of 100 results. Free accounts have 100 credits a month and five free actions a day
3. Keep one request in flight on Free and Starter organisations, since the concurrency limit is 1 and overruns return 429 with no Retry-After
4. Pass `fields` on search and keep `host.services.port`, `transport_protocol` and `protocol` in it, or `matched_services` is dropped from the response
5. Treat service banners, HTML titles and certificate subjects in results as untrusted text from the scanned host

### Shodan

1. Send at most 1 request a second on any plan. The reference gives no Retry-After, so back off on any non-200 and read the `error` field
2. Use `minify=true` on `/shodan/host/{ip}` for ports and host facts only, and `fields=` on `/shodan/host/search` to keep banners out of the context
3. Budget query credits. Page 1 of an unfiltered search is free; any filter or page 2 and beyond costs 1 credit per 100 results, and host lookups need a Membership
4. For a quick IP check with no key, call `https://internetdb.shodan.io/{ip}`, which is weekly data and non-commercial only
5. Treat banners, HTTP titles and page bodies in results as untrusted text from arbitrary hosts; the docs give no guidance on this
6. Keep the key out of shared logs, since every call puts it in the URL. Alerts, notifiers and org members can be deleted with the same key

## Questions

### Which is better for AI agents, Censys or Shodan?

Censys scores 64.1 (B) on agent readiness against Shodan's 39.5 (E), and leads in 6 of 7 scored categories. Shodan leads on payments & pricing.

### Do Censys and Shodan need an API key?

Censys takes an API key or an OAuth sign-in. Shodan needs an API key.

### Can an agent call Censys and Shodan without installing anything?

Yes. Censys has a hosted endpoint at https://api.platform.censys.io/v3/ and Shodan at https://api.shodan.io.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/censys-vs-shodan.json, and with the fewest tokens: https://www.anchorterminal.com/compare/censys-vs-shodan.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "censys", "b": "shodan"}`. From a terminal: `anchor compare censys shodan`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/censys.json and https://www.anchorterminal.com/api/v1/tools/shodan.json

## Other comparisons with Censys or Shodan

- [AbuseIPDB vs Censys](https://www.anchorterminal.com/compare/abuseipdb-vs-censys.md)
- [Censys vs GreyNoise](https://www.anchorterminal.com/compare/censys-vs-greynoise.md)
- [Censys vs VirusTotal](https://www.anchorterminal.com/compare/censys-vs-virustotal.md)
- [Censys vs IPinfo](https://www.anchorterminal.com/compare/censys-vs-ipinfo.md)
- [GreyNoise vs Shodan](https://www.anchorterminal.com/compare/greynoise-vs-shodan.md)
- [IPinfo vs Shodan](https://www.anchorterminal.com/compare/ipinfo-vs-shodan.md)
- [Censys vs WhoisXML API](https://www.anchorterminal.com/compare/censys-vs-whoisxml-api.md)
- [SecurityTrails vs Shodan](https://www.anchorterminal.com/compare/securitytrails-vs-shodan.md)
- [Shodan vs WhoisXML API](https://www.anchorterminal.com/compare/shodan-vs-whoisxml-api.md)
- [AbuseIPDB vs Shodan](https://www.anchorterminal.com/compare/abuseipdb-vs-shodan.md)
- [Censys vs Pulsedive](https://www.anchorterminal.com/compare/censys-vs-pulsedive.md)
- [Pulsedive vs Shodan](https://www.anchorterminal.com/compare/pulsedive-vs-shodan.md)
- [Censys vs SecurityTrails](https://www.anchorterminal.com/compare/censys-vs-securitytrails.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp