generated: '2026-07-11'
method: probed
source: live DNS/TLS/HTTP probes of apis.yml + OpenAPI hosts
hosts:
- host: substack.com
  https: true
  tls_version: TLSv1.3
  cert_expires: Aug 22 07:50:09 2026 GMT
  hsts: true
  hsts_max_age: 31536000
- host: support.substack.com
  https: true
  tls_version: TLSv1.3
  cert_expires: Aug 16 23:44:59 2026 GMT
  hsts: true
  hsts_max_age: 259200
domains:
- domain: substack.com
  dnssec: false
  caa: []
  spf: true
  dmarc: true
  dmarc_policy: reject