certpost 1.0.0b9

Let's Encrypt certificate manager with DNS-01 challenges, web admin panel, and TLS termination proxy

certpost

Let's Encrypt certificate manager with DNS-01 challenges, web admin panel, and TLS termination proxy. Written in Go — single static binary, no dependencies. Supports Cloudflare and Technitium DNS Server.

Features

• Automatic certificate issuance — Let's Encrypt via ACME v2, DNS-01 challenges
• Multiple DNS providers — Cloudflare and Technitium DNS Server, with split provider support (e.g. Cloudflare for ACME, Technitium for records)
• Web admin panel — manage domains, view status, download certs, view logs (protected by admin key login)
• DNS management — automatically creates and manages A/CNAME records for your subdomains
• Background renewal — proactively renews the 2 oldest certs daily, with a 30-day expiry safety net
• Per-domain API tokens — each domain gets its own bearer token for certificate retrieval
• TLS termination proxy — built-in proxy with SNI routing and automatic cert refresh
• Certificate fetching — download .crt and .key files via CLI or admin panel
• Interactive setup — certpost-server setup and certpost init wizards for easy configuration
• Single static binary — no runtime dependencies, no openssl required
• Modular DNS — protocol-based design makes it easy to add new providers

Requirements

• Go 1.22+ (for building)
• A supported DNS provider: Cloudflare (API token + zone ID) or Technitium DNS Server (server URL + API token)

Building

make build

Produces output/certpost-server and output/certpost.

Cross-compile for Linux:

make build-linux-amd64
make build-linux-arm64

Server

Initial setup

certpost-server setup -d /path/to/data

This walks you through creating a config.json with your DNS provider settings, base domain, and port. An admin key is generated automatically.

Starting the server

certpost-server run -d /path/to/data

The admin panel is available at http://localhost:8443. Log in with the admin key (printed on startup). From the panel you can:

• Add subdomains — enter an IP address or CNAME target, creates the DNS record via the configured provider, and issues a Let's Encrypt certificate
• View certificate status and expiry dates
• Copy or rotate per-domain API tokens
• Download certificate files
• View server logs

Configuration

The config.json in your data directory. Use a single dns key when one provider handles everything:

{
  "base_domain": "example.com",
  "admin_key": "auto-generated-admin-key",
  "bind": "0.0.0.0",
  "port": 8443,
  "dns": {
    "provider": "cloudflare",
    "api_token": "your-cloudflare-api-token",
    "zone_id": "your-zone-id"
  }
}

For split configurations, use dns_acme and dns_records:

{
  "base_domain": "example.com",
  "admin_key": "auto-generated-admin-key",
  "bind": "0.0.0.0",
  "port": 8443,
  "dns_acme": {
    "provider": "cloudflare",
    "api_token": "your-cloudflare-api-token",
    "zone_id": "your-zone-id"
  },
  "dns_records": {
    "provider": "technitium",
    "server_url": "https://dns.example.com",
    "api_token": "your-technitium-api-token",
    "zone": "example.com"
  }
}

Client

Fetch certificates

certpost fetch -s http://certpost:8443 -t <token> -d app.example.com -o /etc/ssl/certs

With automatic refresh every 24 hours:

certpost fetch -s http://certpost:8443 -t <token> -d app.example.com --refresh 24

TLS termination proxy

certpost proxy -c proxy.json

Generate a config interactively

certpost init

Security

• Admin panel is protected by an admin key with cookie-based auth
• Certificate API uses per-domain bearer tokens (not shared)
• Private keys are stored in JSON files — protect the data directory with filesystem permissions
• TLS proxy loads certs directly into memory via tls.X509KeyPair — no temp files

Licence

Released under the Unlicense — public domain.