On Runtime, inbound traffic is free. Each account's first 100 GiB of outbound traffic each month is free. Outbound traffic past that limit costs $0.02 per decimal GB. Traffic that a sandbox serves through previews, custom domains and TCP ports counts as outbound. Traffic over your WireGuard tunnel is not counted. Sandboxes without credit send data for free (pricing).
Why clouds charge for egress
Moving bytes out of a data center costs the provider transit and peering. The charge also makes it more expensive to move data to another provider. For this reason, egress is often called a lock-in fee. Two published examples show the range:
- AWS gives "100 GB of free data transfer out to the internet free each month, aggregated across all AWS Services and Regions", then bills per GB in tiers.
- Cloudflare R2 lists egress, "data transfer to Internet", as free. It charges for storage and operations instead.
What counts as egress
| Traffic | Usually billed as egress? | On Runtime |
|---|---|---|
| Data your machine sends to the internet | Yes | Yes, past the free allowance |
| Data your machine downloads | No | No |
| Replies to visitors of a site you host | Yes | Yes, through previews, domains, ports |
| Traffic to your own network | Often, at a lower rate | No, over a WireGuard tunnel |
Egress and agent sandboxes
An agent's outbound traffic is mostly small. It includes API calls to a model,
package installs and git clone. At $0.02 per GB, 1 TB past the
allowance costs $20.00. The larger risk is where the data
goes, not the bill. Egress control decides this.
Turn off a sandbox's internet, or allow only the hosts it needs.
Related
Sources
Checked 25 October 2026.