Custom Domains for Portals and Shares
Brand your Fastio portals and shares with your own domain. Full custom domain support with DNS validation, SSL certificates, and org-branded login pages.
Your portals and shares can now live on your own domain.
Instead of sharing links like go.fast.io/s/abc123, you can now use files.yourcompany.com or any subdomain you control. This works for content portals, shared folders, and file transfers.
How It Works
Head to your workspace settings and open the Custom Domains section. Add any subdomain you own, and we’ll walk you through the DNS setup. Point a CNAME record to our servers, and we handle the rest: DNS validation, SSL certificate provisioning, and automatic HTTPS.
Once your domain is active, every portal and share in that workspace is accessible through it. Login pages show your organization’s branding. SSO flows work seamlessly across domains. Even the Intercom support widget adapts to the custom domain context.
What’s Included
- DNS validation via Cloudflare DNS for fast, reliable CNAME checks
- Automatic SSL certificates provisioned and renewed through Caddy
- Org-branded login pages that resolve your organization from the hostname
- Full SSO support with cross-domain authentication via signed OAuth state tokens
- Download security controls (off, medium, high) that work across custom domains
- Guest access that works exactly as it does on the default domain
All active custom domains are visible to every workspace member. Pending domains (still validating DNS) are visible only to admins.
Plan Availability
Custom domains are available on paid plans. You can add the domain and validate DNS on any plan, but activation requires an upgrade. The settings UI shows a clear upgrade prompt if you’re on the free tier.
Getting Started
Open any workspace’s settings, scroll to Custom Domains, and add your subdomain. The whole setup takes about five minutes if your DNS propagates quickly.