{
 "metric": "smtp-starttls",
 "segment": "global",
 "anchor": "domain",
 "label": "global domains",
 "population": "domains worldwide",
 "states": [
  "offered",
  "absent"
 ],
 "quiet_failure_states": [
  "absent"
 ],
 "measurement": "Connect to the lowest-preference MX on port 25, `EHLO`, check for the `STARTTLS` capability. Denominator: `has_mx`, further restricted to MXs that answer.",
 "why_it_matters": "If STARTTLS is not offered, every inbound message crosses the internet in plaintext, readable by anything on the path. The domain may have perfect SPF/DMARC and still be handing its mail over in the clear.",
 "limits": "~32% of small-company MXs never answer within a 6s timeout and are excluded, so this is measured over *reachable* mail servers.",
 "data_tier": "smtp",
 "population_predicate": "has_mx",
 "entity_type": "domain",
 "kind": "failure",
 "latest": {
  "day": "2026-08-14",
  "n": 1136,
  "qf_pct": 2.38,
  "ci": [
   1.64,
   3.44
  ],
  "dist": {
   "offered": 97.62,
   "absent": 2.38
  },
  "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
 },
 "series": [
  {
   "day": "2026-08-02",
   "n": 1169,
   "qf_pct": 3.51,
   "ci": [
    2.6,
    4.72
   ],
   "dist": {
    "offered": 96.49,
    "absent": 3.51
   },
   "snapshot": "common-crawl-domain-stratified-c150-g2500-seed20260729"
  },
  {
   "day": "2026-08-04",
   "n": 1146,
   "qf_pct": 2.44,
   "ci": [
    1.7,
    3.51
   ],
   "dist": {
    "offered": 97.56,
    "absent": 2.44
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  },
  {
   "day": "2026-08-05",
   "n": 1150,
   "qf_pct": 2.35,
   "ci": [
    1.62,
    3.39
   ],
   "dist": {
    "absent": 2.35,
    "offered": 97.65
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  },
  {
   "day": "2026-08-07",
   "n": 1134,
   "qf_pct": 2.29,
   "ci": [
    1.57,
    3.34
   ],
   "dist": {
    "offered": 97.71,
    "absent": 2.29
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  },
  {
   "day": "2026-08-14",
   "n": 1136,
   "qf_pct": 2.38,
   "ci": [
    1.64,
    3.44
   ],
   "dist": {
    "offered": 97.62,
    "absent": 2.38
   },
   "snapshot": "common-crawl-domain-stratified-c400-g2500-seed20260729"
  }
 ],
 "license": "CC BY 4.0",
 "source": "https://quietfailures.com/datasets/smtp-starttls/global"
}