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Zipline supports multiple domains, allowing you to serve files from different domains or subdomains. This is useful for branding, organizing uploads, or providing different access URLs.

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How Custom Domains Work

Zipline can serve files from multiple domains simultaneously. When configured:
  • Files can be accessed via any configured domain
  • You can set a default domain for new uploads
  • Users can choose which domain to use for their uploads
  • All domains must point to your Zipline instance

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Configuration

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Setting the Default Domain

The default domain is used for generating URLs when uploading files: 
CORE_DEFAULT_DOMAIN=files.example.com
This domain will be used in:
  • File URLs returned by the API
  • Shortened URLs
  • Email notifications and webhooks

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Configuring Multiple Domains

You can configure additional domains that Zipline will accept requests from: 
DOMAINS=files.example.com,cdn.example.com,uploads.example.org
The DOMAINS configuration is stored in the database (see prisma/schema.prisma:149). You can also manage domains through the admin dashboard after initial setup.

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DNS Configuration

1

Add DNS A/AAAA records

For each domain, create DNS records pointing to your server:A Record (IPv4):
files.example.com    A    203.0.113.1
cdn.example.com      A    203.0.113.1
AAAA Record (IPv6):
files.example.com    AAAA    2001:db8::1
cdn.example.com      AAAA    2001:db8::1
2

Wait for DNS propagation

DNS changes can take up to 48 hours to propagate globally, but usually complete within a few minutes to hours.Verify DNS propagation:
nslookup files.example.com
nslookup cdn.example.com

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Reverse Proxy Configuration

Configure your reverse proxy to accept requests from all domains.

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Nginx

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    
    # List all domains
    server_name files.example.com cdn.example.com uploads.example.org;

    ssl_certificate /etc/ssl/certs/your-cert.crt;
    ssl_certificate_key /etc/ssl/private/your-key.key;

    location / {
        proxy_pass http://localhost:3000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

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Caddy

files.example.com, cdn.example.com, uploads.example.org {
    reverse_proxy localhost:3000
}
Caddy will automatically obtain separate SSL certificates for each domain!

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Apache

<VirtualHost *:443>
    ServerName files.example.com
    ServerAlias cdn.example.com uploads.example.org

    SSLEngine on
    SSLCertificateFile /etc/ssl/certs/your-cert.crt
    SSLCertificateKeyFile /etc/ssl/private/your-key.key

    ProxyPreserveHost On
    ProxyPass / http://localhost:3000/
    ProxyPassReverse / http://localhost:3000/
</VirtualHost>

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SSL Certificates for Multiple Domains

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Let’s Encrypt with Certbot

Obtain a certificate covering all domains: 
sudo certbot --nginx -d files.example.com -d cdn.example.com -d uploads.example.org
Or for Apache: 
sudo certbot --apache -d files.example.com -d cdn.example.com -d uploads.example.org

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Caddy (Automatic)

Caddy automatically obtains and manages certificates for all configured domains: 
files.example.com, cdn.example.com, uploads.example.org {
    reverse_proxy localhost:3000
}

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Cloudflare

If using Cloudflare:
  1. Add all domains to your Cloudflare account
  2. Enable SSL/TLS (Full or Full (strict) mode)
  3. Configure DNS records for each domain
  4. Cloudflare automatically provides SSL certificates

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Use Cases

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Separate Upload and CDN Domains

Use different domains for uploads and file delivery: 
CORE_DEFAULT_DOMAIN=uploads.example.com
DOMAINS=uploads.example.com,cdn.example.com
  • uploads.example.com - Admin interface and uploads
  • cdn.example.com - Public file access
This allows you to apply different caching rules or CDN configurations to your file delivery domain.

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Multiple Brands/Projects

Use different domains for different projects: 
DOMAINS=files.project-a.com,files.project-b.com,shared.cdn.com
Users can choose which domain to use when uploading files.

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Regional Domains

Provide region-specific domains: 
DOMAINS=us.example.com,eu.example.com,asia.example.com
Combine with GeoDNS to route users to the nearest server.

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Managing Domains via Admin Dashboard

After initial setup, you can manage domains through the Zipline admin interface:
  1. Log in as an administrator
  2. Navigate to Settings → Server
  3. Scroll to Domains section
  4. Add or remove domains as needed
  5. Click Save
Ensure DNS and reverse proxy configurations are updated before adding domains in the dashboard, or files may not be accessible.

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HTTPS URL Generation

When using custom domains with HTTPS: 
CORE_RETURN_HTTPS_URLS=true
CORE_DEFAULT_DOMAIN=files.example.com
CORE_TRUST_PROXY=true
This ensures:
  • File URLs use https:// instead of http://
  • Correct domain is used in generated URLs
  • Proxy headers are respected

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Wildcard Domains

For subdomain-based file serving (e.g., user1.files.example.com, user2.files.example.com):

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DNS Configuration

Create a wildcard DNS record: 
*.files.example.com    A    203.0.113.1

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Reverse Proxy Configuration

Nginx: 
server {
    listen 443 ssl http2;
    server_name *.files.example.com;

    ssl_certificate /etc/ssl/certs/wildcard-cert.crt;
    ssl_certificate_key /etc/ssl/private/wildcard-key.key;

    location / {
        proxy_pass http://localhost:3000;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}
Caddy: 
*.files.example.com {
    reverse_proxy localhost:3000
}

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Wildcard SSL Certificate

Certbot with DNS challenge: 
sudo certbot certonly --manual --preferred-challenges dns -d "*.files.example.com"
Wildcard certificates require DNS validation. You’ll need to add a TXT record during the challenge.

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Troubleshooting

Check:
  • DNS records point to correct server IP: nslookup your-domain.com
  • Domain is listed in DOMAINS configuration or admin dashboard
  • Reverse proxy accepts requests for the domain
  • SSL certificate covers the domain
  • Firewall allows traffic on ports 80/443
This happens when CORE_DEFAULT_DOMAIN isn’t set correctly:
  • Verify CORE_DEFAULT_DOMAIN matches your primary domain
  • Restart Zipline after changing configuration
  • Clear any cached URLs in ShareX or other clients
  • Ensure SSL certificate covers all domains (use SAN certificate or separate certs)
  • For Let’s Encrypt, include all domains in the certbot command
  • For Caddy, it automatically handles multiple domains
  • Check certificate details: openssl s_client -connect domain.com:443 -servername domain.com
This occurs when Cloudflare SSL mode is misconfigured:
  • Set Cloudflare SSL mode to Full or Full (strict)
  • Ensure CORE_RETURN_HTTPS_URLS=true is set
  • Verify reverse proxy doesn’t force HTTP redirects
  • Check reverse proxy Host header is being passed: proxy_set_header Host $host;
  • Verify CORE_TRUST_PROXY=true is set
  • Ensure no conflicting server blocks in reverse proxy config

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Best Practices

  • Use descriptive domains: files.example.com, cdn.example.com instead of random subdomains
  • Plan your structure: Decide on domain purposes before deploying
  • Document your setup: Keep track of which domains serve which purposes
  • Monitor all domains: Set up monitoring for all configured domains
  • Consistent SSL: Ensure all domains have valid SSL certificates
  • DNS TTL: Use reasonable TTL values (e.g., 300-3600 seconds) for easier updates
Consider using a CDN like Cloudflare, CloudFront, or BunnyCDN in front of your custom domains for better performance and DDoS protection.

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