TLS Checker API

GET

Check supported TLS versions and highest negotiable protocol for any domain.

TLS Check inspects which TLS/SSL protocol versions a server supports. It probes TLS 1.0 through 1.3, reports which are negotiable, and derives a security verdict — the highest supported version, whether deprecated protocols are still exposed, and a composite risk score.

Try it — live request, no key required

Request

GETapi.apiverve.com/v1/tlscheck?domain=amazon.com

Query parameters

domainstring

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "domain": "amazon.com",
    "tlsVersions": {
      "TLSv1": true,
      "TLSv1.1": true,
      "TLSv1.2": true,
      "TLSv1.3": true
    },
    "highestVersion": "TLSv1.3",
    "hasDeprecatedTLS": true,
    "isSecure": false,
    "riskScore": 55,
    "riskLevel": "medium"
  }
}

About the TLS Checker API

TLS Check connects to the provided domain and port and runs a TLS handshake for each protocol version to determine which are supported. It identifies the highest negotiable version (like TLS 1.2/1.3), flags whether deprecated TLS 1.0/1.1 remain exposed, and returns a composite risk score summarizing the server's protocol security.

What people use it for

Payment Gateway Auditing: Before onboarding merchant checkout domains, fintech compliance auditors check whether incoming endpoints accept legacy protocols like TLS 1.0 or 1.1.
Deployment Pipeline Verification: Flag outdated web server configurations during production releases by testing handshake support across all modern protocol versions before traffic switches over.
Attack Surface Scanning: Security analysts query customer-facing domains periodically to find legacy protocol support and review the highest negotiable version across exposed web ports.
Vendor Security Assessments: When evaluating SaaS suppliers, procurement teams inspect external hostnames to confirm that partner servers negotiate TLS 1.2 or 1.3.

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
GraphQL: Query language
MCP: For AI agents

View all integrations →

Other ways to use TLS Checker

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.on VerveSheets Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.on VerveContext

Questions.

Common questions about the TLS Checker API.

Read the docs →

Which TLS versions does the check test against?

The check runs live handshakes for TLS 1.0, 1.1, 1.2, and 1.3. You can target any standard domain and specify a custom port if the service does not run on standard HTTPS port 443.

Which plan fits 25,000 domain TLS checks a month?

The Starter plan easily covers this volume. Each check costs 2 credits, so 25,000 scans use 50,000 of the 200,000 credits on Starter, working out to about $0.30 per 1,000 calls. The Free plan includes 100 checks each month for testing.

Are the risk score and deprecated protocol flags available on the Free plan?

No, those are premium fields. The Free plan reports raw version support and the highest negotiable TLS version. The composite risk score, risk level band, deprecated TLS flag, and overall security verdict unlock on any paid plan.

Does this check use cached data or scan live?

Every check performs real-time TLS handshakes directly against the destination host and port at the moment of your request. It does not rely on cached or historical scan databases.

What does the response return if a server refuses all TLS connections?

If none of the tested TLS protocols successfully negotiate a handshake, each protocol flag returns false and the highest version field returns null. You can use that null check to detect non-TLS services or connection failures.

Request parameters — GET /v1/tlscheck

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

Parameter	Type	Example	Description
`domain`Required	string	`amazon.com`	The domain to check the TLS/SSL configuration for domain

Optional

Parameter	Type	Example	Description
`port`Optional	integer	`443`	The port to connect to (usually 443 for HTTPS) default 443 · range 1-65535

Example request

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curl "https://api.apiverve.com/v1/tlscheck?domain=amazon.com&port=443" \
  -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.

Header	When	Value
`x-api-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Response — GET /v1/tlscheck

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.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "domain": "amazon.com",
    "tlsVersions": {
      "TLSv1": true,
      "TLSv1.1": true,
      "TLSv1.2": true,
      "TLSv1.3": true
    },
    "highestVersion": "TLSv1.3",
    "hasDeprecatedTLS": true,
    "isSecure": false,
    "riskScore": 55,
    "riskLevel": "medium"
  }
}

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.

Field	Type	Example	Description
`domain`	string	`"amazon.com"`	Domain name that was checked for TLS configuration
`tlsVersions`	object	`{...}`	Whether the server completes a handshake at each protocol version, keyed TLSv1, TLSv1.1, TLSv1.2 and TLSv1.3
`TLSv1`	boolean	`true`	Whether TLS 1.0 protocol is supported by server
`1`	boolean	`true`	Whether TLS 1.1 protocol is supported by server
`2`	boolean	`true`	Whether TLS 1.2 protocol is supported by server
`3`	boolean	`true`	Whether TLS 1.3 protocol is supported by server
`highestVersion`	string	`"TLSv1.3"`	The highest TLS version the server supports (e.g. TLSv1.3), or null if none were negotiable
`hasDeprecatedTLS`Premium	boolean	`true`	Whether the server still supports deprecated TLS 1.0 or 1.1, which are insecure and disallowed by PCI-DSS
`isSecure`Premium	boolean	`false`	Whether the server supports a modern TLS version (1.2/1.3) and does not expose any deprecated version
`riskScore`Premium	number	`55`	Composite 0-100 risk score based on missing modern TLS and exposure of deprecated protocols (higher is riskier)
`riskLevel`Premium	string	`"medium"`	Risk band derived from the score: low, medium or high

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.

Header	What it carries
`x-api-remaining-credits`	Credits left in the current cycle
`x-api-credits-used`	Credits spent in the current cycle
`x-api-max-credits`	The allowance for the cycle
`x-api-version`	Version of the endpoint that answered

Errors

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

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter that has to change.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted here	A key restriction or an IP allow-list — never a bad key.
`429`	Rate limited, or out of credits	Read `error` to tell them apart, then back off or top up.

What a call costs — 2 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.

Plan	Per month	Credits	TLS Checker calls	Per 1,000 calls
Free	Free	200	100	Free
Starter	$29.99	200,000	100,000	$0.30
Pro	$99.99	1,000,000	500,000	$0.20
Mega	$299.99	4,000,000	2,000,000	$0.15

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.

Compare all pricing tiers →

Call it from cURL — GET /v1/tlscheck

No SDK to install — this is a plain HTTPS call to /v1/tlscheck with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/tlscheck" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/tlscheck-apiSource, issues and the examples this page is built from.ReferenceTLS Checker API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/tlschecknpm APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Node.js — GET /v1/tlscheck

Install the Node.js SDK, then call the TLS Checker API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/tlscheck

Node.js

const res = await fetch("https://api.apiverve.com/v1/tlscheck", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/tlscheckThe published Node.js client, versioned and signed.GitHubapiverve/tlscheck-apiSource, issues and the examples this page is built from.ReferenceTLS Checker API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Python — GET /v1/tlscheck

No SDK to install — this is a plain HTTPS call to /v1/tlscheck with your key in the x-api-key header. Swap in a real key and it runs as-is.

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/tlscheck",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

Also published for

@apiverve/tlschecknpm APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from C# / .NET — GET /v1/tlscheck

Install the C# / .NET SDK, then call the TLS Checker API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.TLSChecker

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/tlscheck");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.TLSCheckerThe published C# / .NET client, versioned and signed.GitHubapiverve/tlscheck-apiSource, issues and the examples this page is built from.ReferenceTLS Checker API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/tlschecknpm

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — GET /v1/tlscheck

No SDK to install — this is a plain HTTPS call to /v1/tlscheck with your key in the x-api-key header. Swap in a real key and it runs as-is.

req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/tlscheck", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")

res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))

Resources

Also published for

@apiverve/tlschecknpm APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — GET /v1/tlscheck

No SDK to install — this is a plain HTTPS call to /v1/tlscheck with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/tlscheck");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);

$response = curl_exec($ch);
echo $response;

Resources

Also published for

@apiverve/tlschecknpm APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — GET /v1/tlscheck

No SDK to install — this is a plain HTTPS call to /v1/tlscheck with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/tlscheck")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.body

Resources

Also published for

@apiverve/tlschecknpm APIVerve.API.TLSCheckerNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

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TLS Checker API

Try it — live request, no key required

About the TLS Checker API

What people use it for

Ways to call it

Other ways to use TLS Checker

Questions.

Request parameters — GET /v1/tlscheck

Required

Optional

Authentication

Response — GET /v1/tlscheck

Response fields

Response headers

Errors

What a call costs — 2 credits per call

Call it from cURL — GET /v1/tlscheck

Resources

Also published for

Call it from Node.js — GET /v1/tlscheck

Resources

Also published for

Call it from Python — GET /v1/tlscheck

Resources

Also published for

Call it from C# / .NET — GET /v1/tlscheck

Resources

Also published for

Call it from Go — GET /v1/tlscheck

Resources

Also published for

Call it from PHP — GET /v1/tlscheck

Resources

Also published for

Call it from Ruby — GET /v1/tlscheck

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — TLS Checker API

Networking

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