HOW.IS
?

How is readthedocs.io?

Looks fine risk 0/100

Registered 12 years ago, on no blocklists we checked, valid HTTPS, the site answered 200 in 213 ms.

Why

02050100
finecarefulhigh risk
  • ·Nothing in the checks added risk.

Rule-based: domain age, blocklists, TLS. A heuristic, not a guarantee.

How readthedocs.io looks right now
The home page, rendered by how.is in a sandboxed browser. Nothing on it is clickable here.
Site
200
213 ms · ends at about.readthedocs.com
HTTPS
56 d
left on a Google Trust Services certificate
Age
12 years
registered 2014-06-14
Blocklists
0
listings across 5 lists

Everything we looked at

DNS records5 record types
A104.16.253.120
104.16.254.120
AAAA2606:4700::6810:fd78
2606:4700::6810:fe78
MX1 aspmx.l.google.com
10 aspmx3.googlemail.com
10 aspmx2.googlemail.com
5 alt1.aspmx.l.google.com
5 alt2.aspmx.l.google.com
NSivan.ns.cloudflare.com
tegan.ns.cloudflare.com
CAA{'type': 'CAA', 'issue': ' amazontrust.com', 'critical': 0}
{'type': 'CAA', 'issue': 'comodoca.com', 'critical': 0}
{'type': 'CAA', 'critical': 0, 'issuewild': 'amazonaws.com'}
{'type': 'CAA', 'critical': 0, 'issuewild': 'ssl.com'}
{'type': 'CAA', 'critical': 0, 'issuewild': 'comodoca.com'}
{'type': 'CAA', 'issue': 'ssl.com', 'critical': 0}
{'type': 'CAA', 'critical': 0, 'issuewild': 'pki.goog; cansignhttpexchanges=yes'}
{'type': 'CAA', 'issue': 'pki.goog; cansignhttpexchanges=yes', 'critical': 0}
{'type': 'CAA', 'issue': 'digicert.com; cansignhttpexchanges=yes', 'critical': 0}
{'type': 'CAA', 'critical': 0, 'issuewild': 'letsencrypt.org'}
{'type': 'CAA', 'critical': 0, 'issuewild': 'digicert.com; cansignhttpexchanges=yes'}
{'type': 'CAA', 'issue': 'letsencrypt.org', 'critical': 0}
RegistrationCloudflare, Inc
registrarCloudflare, Inc
registered2014-06-14
expires2028-06-14
last changed2026-08-12
nameserversivan.ns.cloudflare.com
tegan.ns.cloudflare.com
statusclient transfer prohibited
registered 2014-06-14expires 2028-06-14
HTTPS certificate56 days left
validyes
issuerGoogle Trust Services
coversreadthedocs.io, *.readthedocs.io
protocolTLSv1.3
issued 2026-09-24expires 2026-12-23
DNSSECinsecure

Domain is not signed with DNSSEC

. → io → readthedocs.io
Email authenticationpoor
SPFnone
DMARCnone
DKIMnone of 1 common selectors

Whether mail claiming to be from this domain can be checked as genuine.

Security scoregrade B · 145/205
Basic Security
10/40missing: DNSSEC Enabled, Nameserver Diversity
Record Security
15/45missing: SPF Record, DMARC Record, DKIM Presence
Advanced Security
25/25
Domain Reputation
50/50
Threat Detection
45/45missing: Domain Age Check
Blocklists0 listings · 8 lookups
SURBL MultidomainURIBL MultidomainSpamCop104.16.254.120Barracuda104.16.254.120UCEPROTECT Level 1104.16.254.120SpamCop104.16.253.120Barracuda104.16.253.120UCEPROTECT Level 1104.16.253.120

Green: clean. Red: listed. Grey: the list did not answer.

Ask it yourself

Agents get this as data. Bought through the API, the checks behind this page cost $0.070: profile $0.025 + trust $0.020 + screenshot $0.020 + site status $0.005.

curl "https://how.is/v1/domain/trust?domain=readthedocs.io" \ -H "Authorization: Bearer $HOWIS_KEY" # or pay per call in USDC (x402), no key: the 402 tells your agent the price curl -i "https://how.is/v1/domain/profile?domain=readthedocs.io"

MCP: add https://how.is/mcp to Claude, Codex or Cursor (one-line install) and ask for domain_trust on readthedocs.io. Reference: /llms.txt.

Watch readthedocs.io. DNS read at the source every 5 minutes; certificate, blocklists and expiry every 6 hours. You get an email only when something changes.

Watch — $1 / 30 days