TLS Configuration

Which TLS protocol versions a hostname accepts, what it negotiates by default (version, cipher, ALPN, SNI), certificate trust, and handshake timing, measured from this server. A protocol result is "supported", "not-supported", or "unable-to-test" when the check could not reach a clean verdict. Costs 4 credits per request.

Cost: 4 credits per request, out of 300 per day.

Test in Web Console

Parameter	Type	Required	Description
`domain`	string	Yes	Hostname or https:// URL (reduced to its hostname). Private and internal addresses are rejected.

Example request

curl "https://netsh.io/api/v1/tls-configuration?domain=example.com&api_key=YOUR_API_KEY"

Example response

{
  "ok": true,
  "data": {
    "domain": "example.com",
    "ip": "172.66.147.243",
    "families": [
      { "family": 4, "ip": "172.66.147.243", "status": "ok", "version": "TLSv1.3", "cipher": "TLS_AES_256_GCM_SHA384", "alpn": "h2", "certFingerprint": "61:53:A9:6F:...:22:00", "totalMs": 53, "error": null },
      { "family": 6, "ip": "2606:4700:83b5:72db:f20d:0:ef6b:ff98", "status": "ok", "version": "TLSv1.3", "cipher": "TLS_AES_256_GCM_SHA384", "alpn": "h2", "certFingerprint": "61:53:A9:6F:...:22:00", "totalMs": 51, "error": null }
    ],
    "protocols": [
      { "version": "TLSv1.3", "result": "supported" },
      { "version": "TLSv1.2", "result": "supported" },
      { "version": "TLSv1.1", "result": "supported" },
      { "version": "TLSv1", "result": "supported" }
    ],
    "negotiated": { "version": "TLSv1.3", "cipher": "TLS_AES_256_GCM_SHA384", "alpn": "h2", "http2": true },
    "sni": { "sent": true, "required": true },
    "certificate": {
      "ok": true,
      "subject": "example.com",
      "issuer": "Cloudflare TLS Issuing ECC CA 3",
      "validFrom": "2026-07-29T22:10:08.000Z",
      "expiryDate": "2026-10-27T22:17:21.000Z",
      "daysRemaining": 35,
      "hostnameMatch": true,
      "hostnameMismatchReason": null,
      "chainLength": 4,
      "trusted": true,
      "trustError": null
    },
    "timing": { "tcpMs": 26, "tlsHandshakeMs": 27, "totalMs": 53 },
    "connectionError": null
  },
  "meta": { "tool": "tls-configuration", "version": "v1" }
}

SSL Certificate Checker