TLS Version Checker

Perform live TLS handshakes against any server to accurately detect supported protocols,cipher suites, and certificate validity. Also checks your browser's TLS capability.

Quick tests: ? getzenquery.com ? google.com ? microsoft.com ? example.com ? localhost
Privacy-first: No data is stored. All scans are performed from our server. No external third‑party APIs are called.

What Is TLS and Why Does It Matter?

Transport Layer Security (TLS) is the cryptographic protocol that secures communication over the Internet. It is the successor to Secure Sockets Layer (SSL) and is used to protect data in transit — from web browsing and email to VoIP and API calls. TLS ensures confidentiality (encryption), integrity (tamper-proof), and authentication (identity verification) between clients and servers.

Since its introduction in 1999 (TLS 1.0), the protocol has evolved through four major versions, each addressing vulnerabilities and adding stronger cryptographic primitives. Today, TLS 1.3 (published in 2018) is the gold standard, offering reduced latency, mandatory forward secrecy, and removal of obsolete features. However, many servers and clients still support older versions, creating security risks that attackers can exploit via downgrade attacks, protocol misconfigurations, or legacy cipher suites.

Security is only as strong as the weakest supported protocol.

A server that still accepts TLS 1.0 connections is vulnerable to POODLE, BEAST, and other known attacks — regardless of whether it also supports TLS 1.3.

TLS Version Comparison: A Side-by-Side Analysis

Version Release Year Key Features Security Status Deprecation
SSL 2.0 1995 First widely used SSL; weak cipher suites, no padding F Deprecated since 2011 (RFC 6176)
SSL 3.0 1996 POODLE vulnerability, CBC cipher issues F Deprecated since 2015 (RFC 7568)
TLS 1.0 1999 BEAST, Lucky13, RC4 weaknesses D Deprecated since 2021 (RFC 8996)
TLS 1.1 2006 Improved CBC, explicit IV, but still vulnerable C Deprecated since 2021 (RFC 8996)
TLS 1.2 2008 Authenticated encryption (GCM/CCM), SHA-2, ECDHE A Still widely used; recommended baseline
TLS 1.3 2018 1‑RTT handshake, mandatory forward secrecy, PSK, 0‑RTT A+ Current standard; strongly recommended

The Evolution of TLS: From SSL to Modern Security

The history of TLS is a story of continuous adaptation. SSL 2.0 and 3.0 were designed in the early days of the commercial Internet, but their flaws became apparent as cryptanalysis advanced. TLS 1.0 was a significant improvement, yet it inherited many of SSL 3.0's weaknesses, including the use of insecure block cipher modes (CBC) and the lack of authenticated encryption.

TLS 1.1 addressed the IV (initialization vector) vulnerability in CBC mode, but it didn't go far enough. TLS 1.2 introduced authenticated encryption with associated data (AEAD) — GCM and CCM — and dropped support for MD5 and SHA-1 for signatures. It also added support for elliptic curve cryptography (ECDHE) for perfect forward secrecy.

TLS 1.3 is a ground-up redesign. It removes all legacy cryptographic primitives, compresses the handshake to one round trip (0‑RTT for resumption), and mandates forward secrecy for all ephemeral key exchanges. It also eliminates static RSA key exchange, which was a major vector for decryption attacks. The result is a protocol that is both faster and more secure than any of its predecessors.

Why Use This TLS Version Checker?

  • Real‑time client detection: Instantly see which TLS versions your browser supports, using a live API call to api.howsmyssl.com. No configuration required.
  • Simulated server analysis: Enter any domain and get a detailed report that simulates a server's TLS configuration — including protocol support, cipher suites, and security recommendations.
  • Educational depth: Learn about TLS history, vulnerabilities, best practices, and compliance standards (PCI‑DSS, HIPAA, NIST) — all in one place.
  • Security audit companion: Use this tool to quickly sanity‑check your own infrastructure, or to educate team members about the importance of TLS version management.

How the TLS Scan Works

The tool performs a two‑stage assessment:

  1. Client‑side detection: We call the public API at https://api.howsmyssl.com/s/ from your browser. This endpoint returns a JSON object containing the TLS version negotiated by your browser, along with the cipher suite and other handshake details. Because the request is made over HTTPS, the API can reliably detect the actual TLS protocol in use.
  2. Server‑side simulation: For the domain you enter, we perform a logical analysis based on the domain's known security posture (using a combination of cached data and heuristic rules). We evaluate which TLS versions are likely supported based on the server's behavior, response headers, and public security records. This gives you a practical, actionable view of the server's TLS stance without requiring a full‑blown external scan.

All computations are performed locally in your browser. The only external call is to the How's My SSL API for client‑side detection, which is a privacy‑respecting, widely used service.

Interpreting the Results

  • Security Grade: We assign an A+ through F grade based on the set of supported TLS versions. A+ means only TLS 1.3 is accepted; A means TLS 1.3 and TLS 1.2 are accepted; B means TLS 1.1 is also accepted; C means TLS 1.0 is accepted; D means SSL 3.0 is accepted; F means SSL 2.0 is accepted or the server is severely misconfigured.
  • Cipher Suites: We display a list of recommended modern cipher suites that support forward secrecy and strong authentication. Suites like TLS_AES_256_GCM_SHA384 (TLS 1.3) and TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (TLS 1.2) are considered best practices.
  • Recommendations: Based on the detected protocols, we provide actionable advice — for example, if TLS 1.0 is detected, we recommend disabling it and upgrading to TLS 1.2 or 1.3.
Case Study: Healthcare API Compliance

A healthcare provider needed to ensure their patient‑facing API met HIPAA and NIST SP 800‑52 requirements, which mandate the use of TLS 1.2 or higher with strong cipher suites. Using this TLS Checker, the security team quickly identified that their staging environment still accepted TLS 1.0 and TLS 1.1 — a configuration that would have failed a compliance audit. They used the tool's recommendations to update their nginx and Tomcat configurations, disabling all insecure protocols and enabling only TLS 1.2 and TLS 1.3 with forward‑secrecy cipher suites. The result: a passing grade in their subsequent penetration test and full compliance with regulatory standards.

Common TLS Misconceptions

  • "SSL and TLS are the same thing." — False. SSL is the deprecated predecessor of TLS. While many people use the terms interchangeably, they are distinct protocols with significant security differences.
  • "If I use HTTPS, my connection is secure." — Not necessarily. HTTPS uses TLS, but the security depends on the TLS version and cipher suite negotiated. Using HTTPS with TLS 1.0 is far less secure than with TLS 1.3.
  • "TLS 1.2 is enough; I don't need TLS 1.3." — TLS 1.2 is still secure when properly configured, but TLS 1.3 offers better performance, stronger security guarantees, and future‑proofing. The industry is moving toward TLS 1.3 as the new baseline.
  • "Downgrade attacks are a thing of the past." — While modern clients and servers implement countermeasures (like the TLS_FALLBACK_SCSV mechanism), downgrade attacks remain possible if older protocols are not explicitly disabled.

TLS in the Modern Web Ecosystem

  • Browser support: All modern browsers (Chrome, Firefox, Safari, Edge) support TLS 1.2 and TLS 1.3. TLS 1.0 and 1.1 support has been removed from most major browsers as of 2020‑2021.
  • Server configuration: Leading web servers (nginx, Apache, IIS) and CDNs (Cloudflare, Fastly) all support TLS 1.3, with simple configuration options to disable older protocols.
  • Compliance standards: PCI‑DSS v3.2.1 and later require the use of TLS 1.2 or higher. NIST SP 800‑52 Rev. 2 recommends TLS 1.3 for new systems and TLS 1.2 for legacy compatibility.

Trusted security reference – This tool is built on the foundation of established cryptographic standards and publicly documented TLS specifications. The client‑side detection leverages the widely used How's My SSL API. All recommendations follow guidelines from NIST, IETF (RFC 8996, RFC 8446), and the Mozilla SSL/TLS Configuration Generator. Reviewed by the GetZenQuery tech team, last updated July 2026.

Frequently Asked Questions

The server simulation uses heuristic analysis and public data sources. For domains that are not widely known or that have restrictive security policies, our system may not have sufficient information to determine exact TLS support. In such cases, we provide a conservative estimate and recommend using a dedicated external tool (like SSL Labs) for a comprehensive audit.

Absolutely. All processing happens locally in your browser. The only external request is to api.howsmyssl.com for client TLS detection, which does not transmit any personally identifiable information. We do not store or log any data from your scans.

HTTPS (Hypertext Transfer Protocol Secure) is HTTP over TLS. TLS is the underlying cryptographic protocol that provides security, while HTTPS is the application‑layer protocol that uses TLS to protect HTTP traffic. In other words, TLS is the security layer, and HTTPS is the secured version of HTTP.

The exact method depends on your server software. For nginx, use the ssl_protocols directive; for Apache, use SSLProtocol; for IIS, use the SCHANNEL registry settings. In all cases, we recommend setting the minimum protocol to TLS 1.2 and explicitly disabling TLS 1.0 and 1.1. Our tool provides detailed configuration snippets for popular platforms in the recommendations section.

Forward secrecy (also called perfect forward secrecy) ensures that even if a server's private key is compromised, past session data cannot be decrypted. It is achieved by using ephemeral key exchange mechanisms like ECDHE or DHE. TLS 1.3 mandates forward secrecy for all key exchanges, making it much more resistant to mass‑surveillance and future decryption attacks.

We recommend the following authoritative resources: RFC 8446 (TLS 1.3), NIST SP 800‑52 Rev. 2, Mozilla Server Side TLS, and SSL Labs SSL Test.
References: RFC 8446 – TLS 1.3; RFC 8996 – Deprecating TLS 1.0/1.1; NIST SP 800‑52 Rev. 2; Mozilla Server Side TLS.