SSL Certificate Checker API

About the SSL Certificate Checker API

SSL Checker works by fetching the live SSL certificate of the website provided and returning its details — issuer, subject, validity dates and key strength — along with derived checks computed from the certificate: current validity, days until expiry, an expiring-soon flag, and self-signed detection.

What people use it for

Expiring Certificate Alerts

DevOps teams check domain validity dates daily to send renewal alerts before certificates expire and cause browser warnings.

Customer Domain Audits

When clients point custom hostnames to a SaaS platform, automated onboarding scripts verify validity status and key strength before activating traffic.

Weak Cipher Detection

Flag outdated configurations across corporate web properties by checking whether deployed certificates meet minimum encryption key bit lengths.

Partner Domain Verification

To prevent broken checkouts, e-commerce marketplaces inspect partner payment gateways to confirm validity windows before routing shopper transactions.

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON

Default REST response

XML

Markup format

YAML

Human-readable

CSV

Tabular export

Beta

GraphQL

Query language

New

MCP

For AI agents

Request parameters — GET /v1/sslchecker

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

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curl "https://api.apiverve.com/v1/sslchecker?domain=ebay.com" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Response — GET /v1/sslchecker

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

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{
  "status": "ok",
  "error": null,
  "data": {
    "subject": {
      "C": "US",
      "ST": "California",
      "O": "eBay, Inc.",
      "CN": "ebay.com"
    },
    "issuer": {
      "C": "GB",
      "O": "Sectigo Limited",
      "CN": "Sectigo Public Server Authentication CA OV R36"
    },
    "subjectaltname": "DNS:ebay.com, DNS:befr.ebay.be, DNS:benl.ebay.be, DNS:cafr.ebay.ca, DNS:e-bay.it, DNS:ebay.at, DNS:ebay.be, DNS:ebay.ca, DNS:ebay.ch, DNS:ebay.co.uk, DNS:ebay.com.au, DNS:ebay.com.hk, DNS:ebay.com.my, DNS:ebay.com.sg, DNS:ebay.de, DNS:ebay.es, DNS:ebay.fr, DNS:ebay.ie, DNS:ebay.in, DNS:ebay.it, DNS:ebay.nl, DNS:ebay.ph, DNS:ebay.pl, DNS:ebay.us, DNS:ebay.vn, DNS:wwww.ebay.co.uk, DNS:wwww.ebay.com, DNS:wwww.ebay.com.au, DNS:wwww.ebay.de, DNS:wwww.ebay.in, DNS:wwww.ebay.it",
    "infoAccess": {
      "CA Issuers - URI": [
        "http://crt.sectigo.com/SectigoPublicServerAuthenticationCAOVR36.crt"
      ],
      "OCSP - URI": [
        "http://ocsp.sectigo.com"
      ]
    },
    "ca": false,
    "bits": 2048,
    "valid_from": "Jul 28 00:00:00 2025 GMT",
    "valid_to": "Jul 28 23:59:59 2026 GMT",
    "serialNumber": "99F408949A6416EDC3B8F5EC77B2EBE5",
    "domain": "ebay.com",
    "isExpired": false,
    "isValid": true,
    "daysUntilExpiry": 20,
    "isExpiringSoon": true,
    "isSelfSigned": false
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

What a call costs — 10 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Zero-code embed — one snippet, no backend

Drop an interactive SSL Certificate Checker form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.

Changelog — SSL Certificate Checker API

Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.

Currently v1Data refreshed realtime