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Frequently asked questions about shellbox.dev.

Do you support post-quantum encryption?

Yes. Our SSH server supports the sntrup761x25519-sha512@openssh.com hybrid key exchange — a combination of the post-quantum NTRU Prime algorithm and classical X25519. OpenSSH 9.0+ clients (April 2022 onwards) negotiate this automatically. No configuration needed on your end.

How do I skip the "trust this host?" prompt?

We publish SSHFP DNS records secured with DNSSEC. This lets your SSH client verify our server's identity cryptographically through DNS, instead of asking you to trust on first use. Add this to your ~/.ssh/config:

Host shellbox.dev
    VerifyHostKeyDNS yes

Then connect normally: ssh shellbox.dev help. No fingerprint prompt.

I don't have an SSH key. How do I get started?

Generate one:

$ ssh-keygen -t ed25519

Press Enter to accept defaults. Then:

$ ssh shellbox.dev help

Your SSH key is your identity. No signup, no email, no password.

Do I need to create an account?

No. Your SSH public key is your account. The first time you connect, your account is created automatically from your key fingerprint. No registration required.

What happens when I disconnect?

Your box pauses. All processes, shell history, and files are preserved in a memory snapshot. Reconnect and everything resumes exactly where you left off. Billing stops while paused.

If you want a box to keep running after disconnect (e.g. for a background job), toggle keepalive: ssh shellbox.dev keepalive <name>

Can I use VS Code, Zed, or other IDEs?

Yes. Full SFTP support means VS Code Remote SSH, Zed, and any IDE with SSH remote capabilities work out of the box. Point your IDE at <name>@shellbox.dev and you're in.

How do HTTPS endpoints work?

Each box gets a public URL like https://dev1-a1b2c3d4.shellbox.dev with automatic TLS. HTTP requests to this URL are proxied to port 80 on your box.

How do email endpoints work?

Each box gets an email address like dev1-a1b2c3d4@in.shellbox.dev. Incoming emails are delivered as HTTP POST requests to /email on your box's HTTPS endpoint.

How do I transfer files?

Standard SCP and SFTP:

$ scp file.txt dev1@shellbox.dev:/root/
$ scp dev1@shellbox.dev:/root/file.txt ./
$ sftp dev1@shellbox.dev

What are the resource limits?

Each box: 2 vCPUs, 4GB RAM, 50GB SSD. Per account: up to 4 running boxes and 16 total boxes. Network bandwidth is shared and may be throttled if it affects other users.

Is my data backed up?

No. We do not perform backups. You are responsible for your data. Use scp or sftp to back up important files. You can also duplicate a stopped box as a point-in-time copy: ssh shellbox.dev duplicate <name> <backup>

Can I access my box from multiple devices?

Yes, if they share the same SSH key. Copy your private key to your other devices, or use an SSH agent. Each unique key fingerprint is a separate account.