# What are egress fees?

Egress fees are what a cloud charges for data that leaves its network. The
charge is usually per gigabyte sent to the internet. Data that comes in is free.

**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](/docs/pricing#network-products)).

## 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](/glossary/egress-control) decides this.
Turn off a sandbox's internet, or allow only the hosts it needs.

## Related

- [What is egress control?](/glossary/egress-control)
- [What is an egress proxy?](/glossary/egress-proxy)
- [What is object storage?](/glossary/object-storage)
- [GiB vs GB](/glossary/gib-vs-gb)

## Sources

Checked 25 October 2026.

- [Amazon EC2 on-demand pricing, data transfer](https://aws.amazon.com/ec2/pricing/on-demand/)
- [Cloudflare R2 pricing](https://developers.cloudflare.com/r2/pricing/)
- [Runtime pricing: network products](/docs/pricing#network-products)