Judge0 alternatives
The 6 alternatives below are grouped by kind of sandbox, and each says what it does differently from Judge0. Start from whatever made you look: missing GPUs, session limits, self-hosting, pricing or isolation.
Why teams look beyond Judge0
The reference open-source online judge: ideal for stateless, time-boxed code evaluation at scale, but not a workspace an agent can return to.
- Stateless by design: no filesystem or process survives between submissions, so multi-step agent work must re-send everything each time
- Documented defaults cap a run at 5 s wall time (20 s maximum) and 256 MB on the hosted configuration
- isolate is a process-level sandbox (namespaces and cgroups), not a VM; the self-host guide for Ubuntu 22.04 requires disabling the unified cgroup v2 hierarchy
- GPL-3.0 licence and the last tagged release dating from April 2024; no compliance certifications are published
Judge0 alternatives, by kind
Hosted sandbox platforms
SDK-driven sandboxes you create, run code in and destroy through an API.
E2B
Open-source cloud sandboxes for AI agents, each a Firecracker microVM, with pause/resume, snapshots and forking.
- Firecracker microVM
- Open source
- Self-hostable
- BYOC
- Pause/resume
How it differs: Code interpreters and short-to-medium-lived agent tasks that need microVM isolation, with an open-source self-host path. The safe default for most agent builders: mature, open source, microVM-isolated and widely supported.
Code execution APIs
Submit code, get output: online judges, compiler APIs and Jupyter kernels as a service.
Codapi
Lightweight Apache-2.0 sandbox server (a 3 MB Go binary) that runs each snippet in a locked-down Docker container, built for interactive documentation, with a hosted cloud at $5/month and free self-hosting.
- Locked-down Docker container
- Open source
- Self-hostable
How it differs: Embedding runnable snippets in docs and courses, or a tiny self-hosted run-code endpoint with strict defaults. The simplest well-hardened run-code server to self-host; fine for doc snippets and stateless tool calls, not for agent workspaces.
JDoodle Compiler API
Credit-metered compile-and-run REST and WebSocket API from the JDoodle online IDE, covering 114 languages, frameworks and databases, with each run costing one credit and a free daily allowance.
- Fresh sandbox per run (unnamed)
How it differs: Low-volume, pay-per-run execution with an interactive stdin stream for teaching and demo products. A convenient credit-metered compiler API for demos and courses; limits and isolation are too thinly documented for untrusted agent workloads at scale.
OneCompiler Code Execution API
Hosted run-code API behind the OneCompiler online IDE: one POST runs a multi-file program in 150+ languages and databases, billed per call or per credit with enterprise tiers that raise the runtime cap to 7-20 s.
- Not documented
How it differs: Cheap, high-volume stateless runs across 150+ languages and databases from a backend. A budget run-code endpoint with transparent pricing but an undocumented sandbox; suitable for simple stateless tool calls, not for workspaces.
Full profile →OneCompiler Code Execution API alternativesWebsite ↗
Piston
MIT-licensed code execution engine that runs each submission in an isolate sandbox inside a Docker container, with a public API at emkc.org restricted to approved non-commercial projects since February 2026.
- isolate in Docker
- Open source
- Self-hostable
How it differs: Self-hosted, stateless execution of untrusted snippets in 80+ languages with isolate-level sandboxing. A solid self-hosted judge engine for stateless snippet execution; treat the public emkc.org API as unavailable for commercial agents.
Sphere Engine
Commercial code execution service from the makers of Ideone and SPOJ: a Compilers API for 80+ languages, a Problems API for test-case grading and a Containers product for multi-file projects, priced by quote.
- Isolated workspace (unnamed)
- Self-hostable
How it differs: Assessment and e-learning products that need a supported, commercially backed compile-and-run API with test-case grading. A commercially supported judge for assessment platforms; agents get a reliable but stateless and quote-priced execution backend.
Judge0 vs alternatives
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Judge0 | isolate (namespaces/cgroups) | Yes | Yes / No | Not documented | 5 s wall (max 20 s) | No / No | No | REST API, Python, JavaScript/TypeScript |
| Codapi | Locked-down Docker container | Yes | Yes / No | 1-3 s per run (claim) | 5 s default | No / No | No | REST API, JavaScript/TypeScript |
| E2B | Firecracker microVM | Yes | Yes / Yes | Not documented | 1 h / 24 h (Pro) | Yes / Yes | No | Python, JavaScript/TypeScript |
| JDoodle Compiler API | Fresh sandbox per run (unnamed) | No | No / No | Not documented | Not documented | No / No | No | REST API |
| OneCompiler Code Execution API | Not documented | No | No / No | Not documented | 7-20 s (enterprise) | No / No | No | REST API |
| Piston | isolate in Docker | Yes | Yes / No | Not documented | 3 s run / 10 s compile | No / No | No | REST API |
| Sphere Engine | Isolated workspace (unnamed) | No | Yes / No | Not documented | 5 s (1-15 s) | No / Not documented | No | REST API, PHP, Python, JavaScript/TypeScript |
Frequently asked questions
What are the main alternatives to Judge0?
Cite this page
Agent Sandboxes. (2026). Judge0 alternatives. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/alternatives/judge0/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.