# Censys vs SecurityTrails

> Censys scores 64.1 (B) to SecurityTrails's 30.7 (F) for secintel exposure. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/censys-vs-securitytrails
- Markdown: https://www.anchorterminal.com/compare/censys-vs-securitytrails.md (~4,600 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: 2026-11-04

Censys scores 64.1 (B) on agent readiness against SecurityTrails's 30.7 (F), and leads in every scored category. Both do secintel exposure.

- Censys: grade B, 64.1/100, rank #439 of 1349. Markdown https://www.anchorterminal.com/tools/censys.md · JSON https://www.anchorterminal.com/api/v1/tools/censys.json
- SecurityTrails: grade F, 30.7/100, rank #1268 of 1349. Markdown https://www.anchorterminal.com/tools/securitytrails.md · JSON https://www.anchorterminal.com/api/v1/tools/securitytrails.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 20
- Schema & documentation, 82 against 54
- Agent ergonomics, 79 against 56
- Security & auth, 55 against 32
- Payments & pricing, 35 against 0
- Maintenance & community, 84 against 5
- Transparency & trust, 64 against 32

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

### SecurityTrails (F)

Good for: An agent investigating a domain's DNS and WHOIS history, subdomains and associated infrastructure, where the operator already holds a commercial key.

Watch for: Pricing, terms, privacy, the security page and security.txt on securitytrails.com answered a Cloudflare challenge on 3 November 2026, so none was read


## Why the edge

### Maintenance & community: Censys +79

- 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.
- SecurityTrails (5): The newest dated changelog entry is 28 May 2020, the Project API 1.7.0 entry is undated and the SurfaceBrowser changelog ends on 26 February 2019, so no change within 180 days was found (0 of 30). No entries in the last 90 days (0). A public changelog exists but is five years stale, and the support page is disallowed by robots.txt (3 of 25). No official SDK; the npm package of October 2021 names the vendor as author with no repository (0 of 15). The docs site serves llms.txt and Markdown twins, which shows the documentation platform is current (2 of 10). 0 + 0 + 3 + 0 + 2 = 5.

### Reliability: Censys +35

- 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.
- SecurityTrails (20): Read with the hosted lines. status.securitytrails.com redirects to securitytrails.statuspage.io, which says it is inactive and visible to team members only, so no public status page (0) and no readable history (5). No rate limit numbers in the readable docs; the pricing page, which may carry them, answered a Cloudflare challenge (0). 429 is documented on the ping page with the message 'API rate limit exceeded' and no Retry-After or backoff guidance, and every v1 call is a read (5 of 15). No SLA found (0). The v1 API is live and not marked beta, though every operation id carries an '-old' suffix with deprecated set to false (10). 0 + 5 + 0 + 5 + 0 + 10 = 20.

### Payments & pricing: Censys +35

- Censys (35): No x402, MPP or L402 (0). Starter at $79 a month for 500 credits and Starter Pro at $599 for 4,000 are public in the docs with one credit an action, which gives a per-call price, while Core and higher plans and credit top-ups are priced by sales (15 of 20). A free account gets 100 credits a month and five free actions a day with no card named (20). Signup, token creation and Starter purchase all happen in a browser, and no key API was found (0). 0 + 15 + 20 + 0 = 35.
- SecurityTrails (0): No x402, MPP or L402 (0). securitytrails.com/app/pricing and /corp/pricing answered a Cloudflare challenge, and the docs name no price, so no public price was read (0). Whether a free plan exists couldn't be confirmed; the usage endpoint shows only that each account has a monthly allowance (0). A key comes from a browser signup on securitytrails.com, with no programmatic route found (0). 0 + 0 + 0 + 0 = 0, scored as Contentful and Personio were on 7 October 2026 when their pricing pages were unreadable.

### Transparency & trust: Censys +32

- 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.
- SecurityTrails (32): A closed service whose terms couldn't be read because of the Cloudflare challenge (5 of 30, for a known commercial product with unread terms). The privacy policy was unread and no retention statement or DPA was found (0 of 30). No deprecation policy; the operation ids carry '-old' with deprecated set to false and no notice explains them (0 of 20). No subprocessor or data location statement readable (0 of 20). 5 + 0 + 0 + 0 = 5.

### Schema & documentation: Censys +28

- 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.
- SecurityTrails (54): The reference pages are generated from an OpenAPI document (operation ids, deprecated flags and typed schemas show on each page), but no spec is published for download and docs.securitytrails.com/openapi redirects to 404 (12 of 25). llms.txt with a Markdown twin of every page (10). Each endpoint has a one-line purpose and nothing on when to use it or not (8 of 20). Path and query parameters are typed, the DNS history type is an enum of six values, and the ASI API has enums, operators and a 1 to 1,000 limit, but the v1 filter object is untyped strings and the DSL query is a free string whose grammar isn't documented (8 of 15). Example responses on every page, with errors mostly limited to 400 and a message, 401 and 429 only on the ping page and 422 on the ASI API (8 of 15). Versioned paths (/v1, /v2) and a changelog whose dated entries stop on 28 May 2020, with one undated Project API 1.7.0 entry (8 of 15). 12 + 10 + 8 + 8 + 8 + 8 = 54.

### Agent ergonomics: Censys +23

- 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.
- SecurityTrails (56): `include_ips` on the list endpoints and an `enrichments` list on ASI asset search, which returns only custom tags by default, size responses on part of the surface; v1 lookups return fixed shapes (12 of 25). `page` with `pages` and `max_page` on v1 lists, scroll on the DSL endpoints, cursor pagination with `limit` up to 1,000 and filters with seven operators on the ASI API (16 of 20). Errors are a 400 message, 401 and 429 text strings and 422 detail arrays, with no codes to branch on (8 of 20). The overview says the v1 API is read-only, so retries are safe; the ASI tag endpoints write with no idempotency guidance (14 of 20). One required parameter per lookup besides the key. No official SDK found, and the npm `securitytrails` package from October 2021 has no repository or homepage (6 of 15). 12 + 16 + 8 + 14 + 6 = 56.

## Score by category

| Category | Weight | Censys | SecurityTrails | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 55 | 20 | Censys +35 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 82 | 54 | Censys +28 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 56 | Censys +23 |
| Security & auth | 14% (17.5 this run) | 55 | 32 | Censys +23 |
| Payments & pricing | 10% (12.5 this run) | 35 | 0 | Censys +35 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 5 | Censys +79 |
| Transparency & trust | 7% (8.8 this run) | 64 | 32 | Censys +32 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **64.1 · B** | **30.7 · F** | |

## Facts side by side

| Fact | Censys | SecurityTrails |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Censys, Inc. | SecurityTrails (Recorded Future) |
| Hosted endpoint | `https://api.platform.censys.io/v3/` | `https://api.securitytrails.com/v1/` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Paid |
| 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 | none |
| Tools exposed | 12 | none |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-11-02 | 2020-05-28 |
| Terms last updated | no date given | no document linked |
| Privacy policy last updated | no date given | no document linked |
| Customer content may train models | not found in the text | not read yet |
| Terms restrict automated access | yes | not read yet |
| Terms restrict benchmarking | yes | not read yet |
| Terms or service can change without notice | yes | not read yet |
| Arbitration or class-action waiver | yes | not read yet |
| Popularity | 11 stars | none |

## 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.

**SecurityTrails.** The v1 API is read-only and reaches current and historical DNS, WHOIS, subdomain and SSL records, with llms.txt and a Markdown twin of every reference page. The key is accepted in the query string, the changelog stops in May 2020, the status page is private, and pricing, terms and privacy sat behind a Cloudflare challenge when checked.

## 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

### SecurityTrails

1. Send the key as an `APIKEY` header, never as `?apikey=`, so it stays out of logs
2. Call `GET /v1/account/usage` first and budget against `allowed_monthly_usage`, since limits aren't published and 429 carries no Retry-After
3. Use `GET /v1/history/{hostname}/dns/{type}` with one of a, aaaa, mx, ns, soa or txt, and page with `page` until the `pages` count is reached
4. On the ASI API pass an `enrichments` list, because the default returns only custom tags, and keep the sort fixed while following `next_cursor`
5. Treat DNS TXT values, WHOIS fields and user agent strings as untrusted text from third parties

## Questions

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

Censys scores 64.1 (B) on agent readiness against SecurityTrails's 30.7 (F), and leads in every scored category.

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

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

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

Yes. Censys has a hosted endpoint at https://api.platform.censys.io/v3/ and SecurityTrails at https://api.securitytrails.com/v1/.


## For agents

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

## Other comparisons with Censys or SecurityTrails

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