TLS Configuration Generator
Pick your server and its version, choose a profile and copy a configuration built from the TLSRef Server Side TLS guidelines, the continuation of Mozilla’s. Post-quantum X25519MLKEM768 is switched on wherever your server version can name it. Already running a configuration? Paste it into “Explain my config”.
100% local — everything runs in your browser, nothing is sent to any server
Leave empty for the current release, 1.30.6.
The OpenSSL the server is built with (openssl version). Leave empty for 3.5.9, the long-term-support line.
Groups your server version cannot name are left out, and the notes below say why.
Tells browsers to use HTTPS only for two years.
Only useful while your CA still runs an OCSP responder.
Post-quantum key exchange is on: this configuration names X25519MLKEM768.
# Generated by ecdsa.com from TLSRef guideline 6.0, intermediate profile: nginx 1.30.6 with OpenSSL 3.5.9
# Options: HSTS
http {
server {
listen 443 ssl;
listen [::]:443 ssl;
http2 on;
ssl_certificate /path/to/signed_cert_plus_intermediates;
ssl_certificate_key /path/to/private_key;
# HTTP Strict Transport Security (63,072,000 seconds, needs ngx_http_headers_module)
add_header Strict-Transport-Security "max-age=63072000; includeSubDomains" always;
}
# Intermediate configuration
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ecdh_curve X25519MLKEM768:X25519:prime256v1:secp384r1;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305;
ssl_prefer_server_ciphers off;
# ssl_session_ticket_key is an alternative to the shared session cache
ssl_session_timeout 1d;
ssl_session_cache shared:MozSSL:10m; # about 40,000 sessions
# Redirect plain HTTP to HTTPS
server {
listen 80 default_server;
listen [::]:80 default_server;
return 308 https://$host$request_uri;
}
}
What this configuration sets
- Software
- nginx · 1.30.6 · OpenSSL 3.5.9
- Protocols
- TLSv1.2, TLSv1.3
- TLS 1.3 cipher suites
- TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384, TLS_CHACHA20_POLY1305_SHA256
- TLS 1.2 cipher suites
- ECDHE-ECDSA-AES128-GCM-SHA256, ECDHE-RSA-AES128-GCM-SHA256, ECDHE-ECDSA-AES256-GCM-SHA384, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-ECDSA-CHACHA20-POLY1305, ECDHE-RSA-CHACHA20-POLY1305
- Key-exchange groups
- X25519MLKEM768, x25519, secp256r1, secp384r1
- HSTS
- max-age 63,072,000 seconds
- OCSP stapling
- off
- Oldest compatible clients
- Firefox 31.3.0, Android 4.4.2, Chrome 49, Edge 15 on Windows 10, IE 11 on Windows 10, Java 8u161, OpenSSL 1.0.1l, Opera 20, Safari 9
Notes
- OKPost-quantum key exchange configured: X25519MLKEM768.
- WarningHSTS with includeSubDomains makes browsers refuse plain HTTP on every subdomain for 63,072,000 seconds: make sure all of them serve HTTPS before deploying.
- InfoCertificate key type: ECDSA and RSA.
- InfoECDSA certificate curves: P-256 and P-384.
- InfoRSA certificates: at least 2,048 bits.
- InfoCertificate lifetime: 90 days recommended, at most 366 days per the guideline.
- InfoOldest compatible clients: Firefox 31.3.0, Android 4.4.2, Chrome 49, Edge 15 on Windows 10, IE 11 on Windows 10, Java 8u161, OpenSSL 1.0.1l, Opera 20, and Safari 9.
Sources and license
Configurations follow the TLSRef Server Side TLS guidelines 6.0 (5.8 for the old profile) and the logic of the TLS Configurator, the successor of Mozilla’s SSL Configuration Generator, by April King, Gene Wood, Julien Vehent, Glenn Strauss and contributors. The guideline data and the ported Configurator code are used under the Mozilla Public License 2.0 and kept as separate files; our changes to the ported code are released under the same license.
Node.js, Java, .NET and the system-wide OpenSSL configuration are written by ecdsa.com on the same guidelines.
Where the settings come from
Every configuration on this page follows the TLSRef Server Side TLS guidelines, the community continuation of Mozilla's Server Side TLS guidelines. Guideline 6.0 defines two profiles. Modern allows TLS 1.3 only (RFC 9846, the 2026 revision of RFC 8446) and suits services whose clients are all from 2018 or later. Intermediate adds TLS 1.2 with forward-secret ECDHE and AEAD cipher suites only, and is the right default for almost every public server. The old profile, with TLS 1.0 and 1.1, was dropped in 6.0; the generator takes it from guideline 5.8, as the upstream TLS Configurator does, and says so in the output. TLS 1.0 and 1.1 have been deprecated since RFC 8996, so use the old profile only for clients that cannot do better.
The server templates are a port of the TLS Configurator, the successor of Mozilla's SSL Configuration Generator, covering 24 servers. Node.js, Java, .NET and the system-wide OpenSSL configuration are written by ecdsa.com on the same guidelines, which brings the total to 28. The guideline data and the ported code are licensed under the Mozilla Public License 2.0 and kept in separate files, as that license requires; the attribution under the tool links to both.
Why the version matters
A configuration must parse on the software that loads it. nginx learned http2 on in 1.25.1; Apache staples OCSP
only from 2.4.13; OpenSSL 3.0 refuses TLS 1.0 unless the security level is lowered to 0. The generator knows these
thresholds for every server, starts from the current release of each product, and adapts the output when you enter
an older version. A version that cannot do what the profile asks — the modern profile on a server without TLS 1.3,
say — produces an explanation instead of a configuration that would not start.
Post-quantum key exchange
Guideline 6.0 puts X25519MLKEM768 first in every profile. It is the hybrid of ML-KEM-768 and X25519 standardized in RFC 10024, and current browsers and CDNs negotiate it by default. A group list that names a group the software cannot parse makes many servers refuse to start, while a list that leaves it out silently turns post-quantum key exchange off. So the generator writes the group only where the version can name it: OpenSSL 3.5 for nginx, Apache, HAProxy and the other OpenSSL-based servers, Go 1.24 and Caddy 2.10, Traefik 3.5, JDK 27 for Java servers, Node.js 24.5 or 22.20. Where a server cannot name groups but its library offers the hybrid by default, the configuration keeps that default, and the result says which case applies. The "all hybrids" option adds SecP256r1MLKEM768 and SecP384r1MLKEM1024, built only from NIST-approved components, for servers that need them. How the hybrid works inside the handshake is shown step by step in the illustrated TLS 1.3 handshake and explained in X25519MLKEM768 explained.
HSTS and OCSP stapling
HSTS (RFC 6797) is on by default with a two-year
max-age and includeSubDomains, which makes browsers refuse plain HTTP on every subdomain; the notes remind you to
check that all of them serve HTTPS. OCSP stapling is off by default: since ballot
SC-063 publicly trusted CAs may stop running OCSP responders, and a certificate without an OCSP URL cannot be stapled.
The notes also carry the guideline's certificate advice and the maximum lifetime of public certificates on the day
you generate the configuration (CA/B Forum ballot SC-081) — see the
47-day certificate calculator for the full schedule.
Explain my config
The second tab reads an nginx or Apache httpd configuration you already run. It follows server blocks and virtual
hosts, applies inheritance from the http block or the server configuration, fills unset directives with the
defaults of your nginx or httpd version, and evaluates cipher strings the way OpenSSL 3 builds its list, so
HIGH:!aNULL turns into the exact suites a client may be offered. Findings are graded from critical (SSLv3,
compression, a stapling setup that keeps httpd from starting) to informational, each with its line number. Include
files are not followed: paste them too if they hold TLS settings.
What stays on your machine
Both modes run entirely in your browser; the page sends nothing anywhere. Configurations name the paths of the
certificate and key files, never their contents, and the explainer refuses a pasted private key. A share link puts
the settings — or the pasted configuration — after the # of the address, which browsers never send to a server.
The settings line inside a generated configuration is the same kind of link.
To see what your browser negotiates today, use the post-quantum browser check; to check deployed servers, the bulk domain checker. The differences between the protocol versions are compared in TLS 1.2 vs TLS 1.3 and X25519MLKEM768 vs X25519.