What is infrastructure as a service?
Infrastructure as a service (IaaS) rents out computing, storage and networks on demand, to run any software on, operating system included.
A Runtime sandbox is infrastructure in that sense, a Linux machine with its
own kernel, sudo and a network you control, rented by the second with CPU
billed as measured: $0.025 per active vCPU-hour and $0.0075 per
GiB-hour of memory, with no plan fee. Every new account gets
100 free sandbox hours, no card (pricing).
The NIST definition
NIST's definition of cloud computing, SP 800-145 from September 2011, names three service models. In IaaS "the consumer is able to deploy and run arbitrary software, which can include operating systems and applications", and "does not manage or control the underlying cloud infrastructure". The same document lists five essential characteristics of any cloud:
| Characteristic | In NIST's words, shortened | On Runtime |
|---|---|---|
| On-demand self-service | Provision "without requiring human interaction" | One API call, CLI command or MCP tool |
| Broad network access | "Available over the network" | HTTPS API, SDKs, CLI and a remote MCP server |
| Resource pooling | Resources "dynamically assigned and reassigned" | Shared CPU with a guaranteed floor |
| Rapid elasticity | Scale "outward and inward commensurate with demand" | 100 sandboxes at once, paused ones free up CPU and memory |
| Measured service | Usage "monitored, controlled, and reported" | Per-run usage, CSV export and a daily cost |
IaaS, PaaS and SaaS
| Model | You manage | Example |
|---|---|---|
| IaaS | The operating system and everything above | Virtual machines, sandboxes, disks |
| PaaS | Your application and data | A platform that runs your web app for you |
| SaaS | Nothing but your settings | Email, a CRM |
Agent sandboxes sit at the IaaS end on purpose: an agent needs to install packages, run a shell and open ports, which a platform that hides the machine does not allow.
Related
- What is a bare-metal server?
- What is serverless computing?
- What is an agent sandbox?
- What is per-second billing?
Sources
Checked 27 September 2026.