SandboxAPI — Code Execution API for AI Agents

8 languages. gVisor isolation. Stateful sessions with file and package persistence. Streaming, async polling, and MCP-native tools.

Current API version: 3.3.0 · Base URL via RapidAPI: https://sandboxapi.p.rapidapi.com

Quick Start #

Synchronous execution #

curl -X POST https://sandboxapi.p.rapidapi.com/v1/execute \
  -H "Content-Type: application/json" \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -H "X-RapidAPI-Host: sandboxapi.p.rapidapi.com" \
  -d '{"language":"python3","code":"print(\"Hello, World!\")"}'

Response:

{
  "id": "exec_abc123",
  "status": "completed",
  "language": "python3",
  "stdout": "Hello, World!\n",
  "stderr": "",
  "exit_code": 0,
  "execution_time_ms": 42,
  "memory_used_kb": 8192,
  "timeout": 10,
  "created_at": "2026-06-25T10:00:00Z"
}

Stateful session 3.2.0 #

Sessions hold a sandbox open between calls. Files and installed packages persist for the session's idle TTL (max 30 minutes). Each call still runs in a fresh interpreter, so keep durable state on disk.

# 1. Create a session
curl -X POST https://sandboxapi.p.rapidapi.com/v1/sessions \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"language":"python3","idle_ttl":300}'
# → {"id":"sess_abc","language":"python3","expires_at":"..."}

# 2. Execute — writes durable state to the session filesystem
curl -X POST https://sandboxapi.p.rapidapi.com/v1/sessions/sess_abc/execute \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"code":"from pathlib import Path\nPath(\"state.txt\").write_text(\"42\")"}'

# 3. Execute again — the file is still there
curl -X POST https://sandboxapi.p.rapidapi.com/v1/sessions/sess_abc/execute \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"code":"from pathlib import Path\nprint(int(Path(\"state.txt\").read_text()) * 2)"}'
# → stdout: "84\n"

Package installation in a session 3.3.0 #

curl -X POST https://sandboxapi.p.rapidapi.com/v1/sessions/sess_abc/install \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"manager":"pip","packages":["pandas","numpy"]}'

Supported stable managers for current public runtimes: pip for Python and npm for JavaScript/TypeScript. Top-1k packages per ecosystem are cached for fast installs.

Streaming output 3.1.0 #

curl -N -X POST https://sandboxapi.p.rapidapi.com/v1/execute/stream \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"language":"python3","code":"for i in range(5):\n  print(i); import time; time.sleep(1)"}'
# → SSE events: stdout, stdout, ..., result

Events use the standard SSE format. The terminal event has event: result with a JSON payload that includes exit_code, execution_time_ms, and memory_used_kb.

Async polling 3.1.0 #

curl -X POST "https://sandboxapi.p.rapidapi.com/v1/execute?async=true" \
  -H "X-RapidAPI-Key: YOUR_API_KEY" \
  -d '{"language":"python3","code":"..."}'
# → {"job_id":"job_xyz","status":"queued","poll_url":"/v1/executions/job_xyz"}

curl https://sandboxapi.p.rapidapi.com/v1/executions/job_xyz \
  -H "X-RapidAPI-Key: YOUR_API_KEY"
# Terminal responses include either result or error fields.

Supported Languages #

Request Parameters #

Response Fields #

Error Handling #

SandboxAPI distinguishes between API errors (HTTP 4xx/5xx) and execution errors (HTTP 200 with a status field). Treat any HTTP 200 response as a successful API call — the status tells you whether the user's code ran cleanly.

Pricing & Rate Limits #

All plans include gVisor isolation, 8 languages, stdin, batch execution, streaming output, and the playground. Sessions, package install, and async polling are available on paid plans. See pricing for full details.

Security #

Every execution runs inside an OCI container backed by gVisor (runsc) — a user-space kernel that intercepts syscalls before they reach the host. Combined with strict resource limits, no network egress (default), no persistent storage, and per-request cleanup, this gives you a strictly stronger isolation boundary than container-only sandboxes like raw Docker or Kubernetes.

• gVisor (runsc) wraps every container; user-space syscall filter blocks risky calls before the host kernel sees them.
• Resource limits (CPU, memory, PIDs, file descriptors, disk) are enforced by cgroups and seccomp.
• Network egress is disabled for execution containers. Package installs run through a short-lived install container limited to the internal mirror.
• Synchronous executions retain no data. Async results live for 24h. Session state expires at the idle TTL (max 30 min).

MCP Server #

SandboxAPI is available as an MCP server at https://mcp.sandboxapi.dev/mcp with 5 tools: execute_code, execute_batch, list_languages, get_capabilities, and session_install_packages.

Add to Claude Desktop / Cursor / VS Code:

{
  "mcpServers": {
    "sandboxapi": {
      "url": "https://mcp.sandboxapi.dev/mcp",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

Full integration guide on the MCP page.

Code Examples #

Python (requests)

import requests

resp = requests.post(
    "https://sandboxapi.p.rapidapi.com/v1/execute",
    headers={
        "X-RapidAPI-Key": "YOUR_API_KEY",
        "X-RapidAPI-Host": "sandboxapi.p.rapidapi.com",
    },
    json={"language": "python3", "code": "print(2 + 2)"},
)
data = resp.json()
print(data["stdout"])  # → "4\n"

JavaScript (fetch)

const resp = await fetch("https://sandboxapi.p.rapidapi.com/v1/execute", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-RapidAPI-Key": "YOUR_API_KEY",
    "X-RapidAPI-Host": "sandboxapi.p.rapidapi.com",
  },
  body: JSON.stringify({ language: "javascript", code: "console.log(2 + 2)" }),
});
const data = await resp.json();
console.log(data.stdout); // → "4\n"

Go

req, _ := http.NewRequest("POST", "https://sandboxapi.p.rapidapi.com/v1/execute",
  strings.NewReader(`{"language":"go","code":"package main\nimport \"fmt\"\nfunc main(){fmt.Println(2+2)}"}`))
req.Header.Set("X-RapidAPI-Key", "YOUR_API_KEY")
req.Header.Set("Content-Type", "application/json")
resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()

Changelog #

Read the full release-by-release changelog →