---
title: Riza
slug: riza
url: "https://toolweight.com/options/riza"
homepage: "https://riza.io"
categories: sandbox-providers
last_verified: 2026-01-15
license: CC-BY-4.0
---

# Riza

> WASM-isolated code interpreter API for LLM output, with no filesystem or network.

Riza compiles language runtimes to WebAssembly and runs untrusted code inside a WASM sandbox with no filesystem and no network unless you explicitly grant them. That makes it the strictest isolation model here and the most limited: no package installs, no processes, no shell. For the narrow case of evaluating a model's Python or JavaScript safely and instantly, the constraint is the feature.

## Identity

|  |  |
| --- | --- |
| Name | Riza |
| Company | Riza |
| One-liner | WASM-isolated code interpreter API for LLM output, with no filesystem or network. |
| Site | https://riza.io |
| Docs | https://docs.riza.io |
| Founded | 2024 |
| Funding | Seed |
| Brand | https://toolweight.com/vendors/Riza |
| Compared in | 1 |

## Where it is compared

### [Sandbox providers](https://toolweight.com/compare/sandbox-providers)
Ranked **#20 of 20** on default weights.
| Field | Value | Confidence | Verified | Source | Note |
| --- | --- | --- | --- | --- | --- |
| Cold start | 120 ms | Inferred | - | - | Estimate for an API call executing a short script. WASM instantiation is the cheapest start in the roster. |
| Cold start (claimed) | - | Unknown | - | - | Marketed on isolation rather than latency. |
| Isolation | wasm | Vendor-claimed | 2026-01-15 | https://docs.riza.io | Language runtimes compiled to WebAssembly. |
| Root in guest | ○ | Vendor-claimed | 2026-01-15 | https://docs.riza.io | There is no OS to be root of. |
| Egress control | blocked-by-default | Vendor-claimed | 2026-01-15 | https://docs.riza.io | Filesystem and network are off unless explicitly granted per execution, the strictest default here. |
| Max runtime | 1 min | Inferred | - | - | Executions are short-lived by design. |
| Persistent FS | ○ | Vendor-claimed | 2026-01-15 | https://docs.riza.io | - |
| Snapshot & fork | ○ | Inferred | - | - | - |
| Custom images | ○ | Vendor-claimed | 2026-01-15 | https://docs.riza.io | No package installs: you supply code, not an environment. |
| GPU | ○ | Inferred | - | - | - |
| Runtimes | python, javascript-typescript, ruby, php | Inferred | - | - | - |
| Preview URLs | ○ | Inferred | - | - | - |
| Browser inside | ○ | Inferred | - | - | - |
| File up/download | ◐ | Inferred | - | - | Input and output objects rather than a filesystem API. |
| Sydney region | ○ | Inferred | - | - | - |
| Concurrent limit | - | Unknown | - | - | Rate-limited per plan rather than capped by concurrent sandboxes. |
| MCP server | ◐ | Inferred | - | - | - |
| SDKs | python, typescript, rest-api | Inferred | - | - | - |
| Streaming output | ○ | Inferred | - | - | Output returns on completion. |
| Price / hour | - | Unknown | - | - | Priced per execution and per plan, not per compute-hour. |
| Meter | per-request | Inferred | - | - | - |
| Idle cost | free-when-stopped | Inferred | - | - | Nothing persists, so nothing idles. |
| GitHub stars | - | Inferred | - | - | - |
| Funding | seed | Community-reported | - | - | - |
| Shipped | 2024 | Inferred | - | - | - |
| Positioning | A code interpreter API for safely running code written by LLMs. | Inferred | - | - | - |

**Verdict.** The strictest isolation on the page and the smallest blast radius: no filesystem, no network, no processes unless you ask. That constraint is exactly right for evaluating a model's arithmetic or data transform, and completely wrong for anything that needs to install a dependency.

## Alternatives

- [ascii](https://toolweight.com/options/ascii), Agent orchestration over Telegram, running on box's VM infrastructure.
- [Blaxel](https://toolweight.com/options/blaxel), Agent-first cloud claiming ~25 ms microVM boots from snapshots.
- [box](https://toolweight.com/options/box), Persistent Linux VMs with SSH, per-VM IPv4 and disk-level forking, priced flat.
- [Cloudflare Sandbox](https://toolweight.com/options/cloudflare-sandbox), Container sandboxes driven from a Worker, addressed through Durable Objects.
- [CodeSandbox SDK](https://toolweight.com/options/codesandbox-sdk), Firecracker VMs with memory snapshots, from the online IDE, now owned by Together AI.
- [Daytona](https://toolweight.com/options/daytona), Sub-second container sandboxes for agent workloads, from a team that built a dev-env manager.
- [Self-hosted Firecracker](https://toolweight.com/options/diy-firecracker), The baseline: Firecracker on your own metal, plus every hard part you now own.
- [E2B](https://toolweight.com/options/e2b), Open-source Firecracker sandboxes with Python and TypeScript SDKs for AI agents.
- [exe.dev](https://toolweight.com/options/exe-dev), Persistent VMs you SSH into, with root, apt and systemd, on a flat monthly plan.
- [Fly.io Machines](https://toolweight.com/options/fly-machines), Raw Firecracker microVMs with a REST API, durable volumes and 35+ regions.
- [Freestyle](https://toolweight.com/options/freestyle), Run untrusted JavaScript and full dev servers, with git hosting and domains built in.
- [GitHub Codespaces](https://toolweight.com/options/github-codespaces), Devcontainer-backed cloud VMs built for humans, occasionally repurposed for agents.

## Licence and attribution

Data from toolweight (https://toolweight.com), licensed CC-BY-4.0.

- Licence: [CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)
- Canonical HTML: https://toolweight.com/options/riza
- Machine-readable: https://toolweight.com/options/riza.md · https://toolweight.com/api/v1 · https://toolweight.com/mcp
- toolweight takes no affiliate revenue and sells no placements. Corrections: https://toolweight.com/suggest