--- title: Modal slug: modal url: "https://toolweight.com/options/modal" homepage: "https://modal.com" categories: sandbox-providers last_verified: 2026-07-23 license: CC-BY-4.0 --- # Modal > Serverless Python compute with a Sandbox API bolted onto a GPU-first platform. Modal is a serverless runtime for Python workloads built on gVisor, with its own scheduler and years of aggressive container-start engineering behind it. The Sandbox API exposes that infrastructure for running untrusted or agent-generated code, including on GPUs. It is the strongest option here if the sandbox needs to sit next to real ML work, and an awkward fit if you just want a plain Linux box. ## Identity | | | | --- | --- | | Name | Modal | | Company | Modal | | One-liner | Serverless Python compute with a Sandbox API bolted onto a GPU-first platform. | | Site | https://modal.com | | Docs | https://modal.com/docs/guide/sandbox | | Founded | 2021 | | Funding | Series B | | Brand | https://toolweight.com/vendors/Modal | | Compared in | 1 | ## Where it is compared ### [Sandbox providers](https://toolweight.com/compare/sandbox-providers) Ranked **#5 of 20** on default weights. | Field | Value | Confidence | Verified | Source | Note | | --- | --- | --- | --- | --- | --- | | Cold start | 1.5 s | Inferred | - | - | Estimate for a cached CPU image with no warm container. Large images and GPU attachment push this considerably higher. | | Cold start (claimed) | 1 s | Vendor-claimed | 2026-01-15 | https://modal.com/docs/guide/cold-start | Marketed as sub-second container starts. Recorded at 1000 ms, the literal ceiling of "sub-second", this page's convention for a claim of that shape. | | Isolation | gvisor | Vendor-claimed | 2026-01-15 | https://modal.com/docs/guide/security | - | | Root in guest | ● | Inferred | - | - | Root inside the sandbox; no host device access. | | Egress control | proxy-logged | Inferred | - | - | Outbound is open by default; proxy and blocking options exist but are not a per-sandbox allowlist. | | Max runtime | 1440 min | Vendor-claimed | 2026-01-15 | https://modal.com/docs/guide/timeouts | 24 h function timeout ceiling. | | Persistent FS | ● | Vendor-claimed | 2026-01-15 | https://modal.com/docs/guide/volumes | Modal Volumes mount into sandboxes and outlive them. | | Snapshot & fork | ◐ | Inferred | - | - | Memory snapshots exist mainly as a cold-start optimisation; forking a live sandbox is not the headline primitive it is at CodeSandbox. | | Custom images | ● | Vendor-claimed | 2026-01-15 | https://modal.com/docs/guide/images | Images are defined in Python or pulled from a registry. | | GPU | ● | Vendor-claimed | 2026-01-15 | https://modal.com/pricing | Self-serve H100, A100, L40S and others. | | Runtimes | python, javascript-typescript, bash, any-oci-image | Inferred | - | - | - | | Preview URLs | ● | Vendor-claimed | 2026-01-15 | https://modal.com/docs | - | | Browser inside | ◐ | Inferred | - | - | Chromium runs fine in a custom image; no supported browser template. | | File up/download | ● | Vendor-claimed | 2026-01-15 | https://modal.com/docs | - | | Sydney region | ○ | Inferred | - | - | US and EU regions. | | Concurrent limit | 100 sandboxes | Inferred | - | - | Default account limits sit in the low hundreds of containers and are raised on request. | | MCP server | ◐ | Inferred | - | - | Examples and community servers rather than a supported product. | | SDKs | python, cli | Inferred | - | - | - | | Streaming output | ● | Vendor-claimed | 2026-01-15 | https://modal.com/docs | - | | Price / hour | $0.238 /hr | Inferred | 2026-07-23 | https://modal.com/pricing | Derived from the Sandbox rate card: $0.00003942/core/s and $0.00000667/GiB/s. Modal bills per physical core, not per vCPU, so this column's 2 vCPU shape is one core: 0.00003942 × 3600 = $0.142, plus 4 × 0.00000667 × 3600 = $0.096, totalling $0.238. Billing the 2 vCPU as 2 cores, the obvious misreading, overstates Modal by about 55%. Expensive per CPU-hour, competitive per GPU-hour. | | Meter | per-second | Vendor-claimed | 2026-01-15 | https://modal.com/pricing | - | | Idle cost | active-cpu-only | Inferred | - | - | Containers scale to zero; a stopped sandbox is not billed. | | GitHub stars | - | Inferred | - | - | - | | Funding | series-b | Community-reported | - | - | Raised a large Series B in 2025. | | Shipped | 2024 | Inferred | - | - | The platform is older; the Sandbox API is the newer surface. | | Positioning | Serverless compute for AI teams, with sandboxes as one primitive. | Inferred | - | - | - | **Verdict.** Buy Modal for the GPU story and the Python ergonomics, not for boot time, it is a serverless compute platform that grew a Sandbox API, and it shows. If your agent needs to run inference next to the code it just generated, nothing else here is close. ## 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/modal - Machine-readable: https://toolweight.com/options/modal.md · https://toolweight.com/api/v1 · https://toolweight.com/mcp - toolweight takes no affiliate revenue and sells no placements. 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