Modal Labs

license

Proprietary

source

closed

service

proprietary Modal managed cloud (no self-host of the gVisor execution plane)

open-part

client SDK only (modal Python/JS client libraries)

pricing

pay-as-you-go usage, free starter credits

Modal Sandboxes is a closed managed service: the client SDK is open, but the execution substrate is a proprietary cloud with no self-host option, so an open client over a closed runtime does not make this open core. Unlike E2B, which ships self-hostable infrastructure, Modal does not.

• https://modal.com/docs/guide/sandbox recorded 2026-06-04

  Sandboxes = secure containers for untrusted agent code, driven via Modal SDK

• https://modal.com/docs/guide/sandbox recorded 2026-08-13

  Redirects to /docs/guide/sandboxes. Sandboxes are still "secure containers for executing untrusted user or agent code on Modal", created only through the Python, JavaScript or Go SDK against Modal's service; no runtime is distributed to run elsewhere.

• https://modal.com/docs/guide/sandboxes recorded 2026-09-29

  Sandboxes guide describes "secure containers for executing untrusted user or agent code on Modal" created through the SDK; searched the body for self-host, on-prem and open source: none.

• https://modal.com/legal/terms recorded 2026-09-29

  Modal Terms of Service bar customers from attempts to "reverse engineer, decompile, disassemble, or" discover the "algorithms of the Service or any software used to provide or make" it available, and name only the modal-client SDK as "available under open source licensing terms", adding "that the Modal Tools are not part of the Service".

• https://modal.com/pricing recorded 2026-09-29

  Modal plan pricing page, with a section headed "Modal Sandbox + Notebooks Pricing", meters Starter, Team and Enterprise plans against Modal compute; searched the body for self-host, on-prem, open source and license: none.

• https://raw.githubusercontent.com/modal-labs/modal-client/main/LICENSE recorded 2026-09-29

  The modal-client repository LICENSE file is the "Apache License" text, "TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION", covering the client SDK only.

Modal publishes no user or usage count for Sandboxes specifically. Its nearest disclosed figure is platform-wide -- a count of Modal teams overall, naming Lovable and Quora as production users running untrusted code -- so the level reflects reported multi-customer traction for the platform rather than a measured figure for the sandbox feature itself.

• https://modal.com/docs/guide/sandbox recorded 2026-06-04

  documented production sandbox feature on a widely-used managed platform

• https://modal.com/docs/guide/sandbox recorded 2026-08-13

  Sandboxes guide publishes lifecycle, image and timeout documentation and no usage, session or customer count.

• https://modal.com/docs/guide/sandboxes recorded 2026-09-29

  Sandboxes guide documents "Sandboxes have a default maximum lifetime of 5 minutes." and other lifecycle details; searched the body for 10,000, customers and usage counts: none.

• https://modal.com/resources/best-code-execution-sandboxes-ai-agents recorded 2026-09-29

  Modal article states "Modal powers infrastructure for over 10,000 teams, with production users like Lovable and Quora running millions of untrusted code snippets daily" with no Sandboxes-specific user count.

Modal Sandboxes isolate each container with gVisor's user-space kernel and support arbitrary custom images, named lookup, GPUs, and sessions from a five-minute default up to 24 hours. That isolation is a step below the microVM platforms, such as Firecracker, that lead the category, and independent ComputeSDK benchmarks place Modal's start-up speed mid-field.

• https://modal.com/docs/guide/sandbox recorded 2026-06-04

  sandbox lifecycle, custom images, timeouts up to 24h, untrusted-code execution

• https://modal.com/docs/guide/sandbox recorded 2026-08-13

  Sandbox lifecycle through the SDK, arbitrary custom images, named/ID lookup, 5-minute default timeout extendable to 24 hours, untrusted-code framing.

• https://modal.com/docs/guide/sandboxes recorded 2026-09-29

  Sandboxes guide states "Sandboxes have a default maximum lifetime of 5 minutes." and documents timeouts up to 24 hours, named Sandboxes, Sandbox.from_id and custom images.

• https://modal.com/resources/best-code-execution-sandboxes-ai-agents recorded 2026-09-29

  Modal article states "Modal uses gVisor containers for isolation" while microVM platforms are named as competitors, and that Sandboxes "can scale to 50,000+ concurrent sessions".

• https://www.computesdk.com/benchmarks/sandboxes/ recorded 2026-09-29

  ComputeSDK benchmark page states "Compare burst time-to-interactive and real-world developer workload results across providers" and its Burst TTI composite leaderboard lists Modal mid-table among 27 providers.