Execution

Run code online

0calls

4 credits / call

Want to add a "run code online" feature to your programming learning site, coding practice platform, or chatbot? This endpoint gives you a secure, isolated cloud code execution environment.

Overview

Submit a piece of source code with its programming language (Python, JS, C/C++, Go, and more). The system compiles and runs it in a cloud sandbox, then returns the full standard output (stdout), standard error (stderr), execution time, and exit status.

Flexible input control Use the stdin parameter to feed the program its standard input stream — perfect for test cases on algorithm problems.

Secure, controlled network policy Code runs in a fully offline environment by default (offline mode). If user code needs to fetch external data, enable public mode and strictly limit the allowed public hosts (e.g. api.github.com) and ports, eliminating malicious network probing at the root.

Usage Notes

Important

An HTTP200 response only means the cloud service received and finished the task — it does not mean the user's code ran successfully. Always rely on the status field in the response body (success means success; other values may be compile_error, runtime_error, or timeout).

Size limits:

Both the source code (code) and standard input (stdin) must not exceed 65536 bytes (UTF-8 encoded).
The execution timeout can be set up to 30000 milliseconds (30 seconds).

About runtime packs (Packs): For now, always pass an empty array []. Do not expose this field to end users for arbitrary input, or uncontrolled dependency loading failures may occur.

Request body

Contains the programming language, source code body, and execution policy parameters. Must pass strict JSON validation.

language

stringrequired

Programming language and its recommended identifier.

code

stringrequired

The full source code. Max 65536 bytes.

stdin

stringoptional

Standard input stream passed to the program. Max 65536 bytes.

timeout_ms

integeroptional

Execution timeout of the user program in milliseconds. Range 1 - 30000.

network

objectoptional

Network access policy of the sandbox. Defaults to offline mode when omitted.

mode

stringoptional

offline: fully disconnected; public: controlled public network access.

allow_hosts

string[]optional

Hosts allowed in public mode (plain domains or IPs only). Max 16 entries.

allow_ports

integer[]optional

Target ports allowed in public mode. Defaults to 80 and 443 when omitted.

packs

string[]optional

Additional runtime packs to load. Always pass an empty array [] or omit for now.

Name	Type	Attributes	Description
`language`	string	required	Programming language and its recommended identifier.
`code`	string	required	The full source code. Max 65536 bytes.
`stdin`	string	optional	Standard input stream passed to the program. Max 65536 bytes.
`timeout_ms`	integer	optional	Execution timeout of the user program in milliseconds. Range 1 - 30000.
`network`	object	optional	Network access policy of the sandbox. Defaults to offline mode when omitted.
`mode`	string	optional	offline: fully disconnected; public: controlled public network access.
`allow_hosts`	string[]	optional	Hosts allowed in public mode (plain domains or IPs only). Max 16 entries.
`allow_ports`	integer[]	optional	Target ports allowed in public mode. Defaults to 80 and 443 when omitted.
`packs`	string[]	optional	Additional runtime packs to load. Always pass an empty array [] or omit for now.

Response

200 / OK

The cloud execution service processed the task successfully. Use the status field in the response body to determine the actual result.

JSON

400 / Bad Request

Invalid request parameters or strict JSON validation failure (e.g. unknown fields, out-of-range lengths).

JSON

413 /

Submitted content is too large. The source code (code) or input stream (stdin) may exceed the 65536-byte limit.

JSON

503 / Service Unavailable

The code execution sandbox is temporarily unavailable or the queue is full. Please retry later.

JSON

504 / Gateway Timeout

Timed out waiting for the execution result, usually due to high system load.

JSON

Quick start

Pick your language to see usage examples

Auth mode:

cURL command

curl -X POST 'https://uapis.cn/api/v1/execution/run' \
  -H 'Authorization: Bearer ' \
  -H 'Content-Type: application/json' \
  -d '{"language": "python", "code": "name = input()
print(f"Hello, {name}!")"}'

Frequently asked questions

Are there any special restrictions for the Run code online API?

Run code online follows our standard usage policy. Refer to the endpoint reference above for the exact rate limits and parameter requirements. Reach out if you have unusual needs.

Are the APIs on UAPI free to use?

UAPI gives every visitor free credits so you can call any endpoint right away. Visitor credits have a usage cap, and if you need more you can for additional credits.

Do I need to register an account to use UAPI?

No registration is required for visitor credit calls. If you need more credits or want to manage your call history, you can register a free account. Signed-in users get more free credits and can review usage details in the console.

Which languages and use cases does UAPI support?

Our APIs follow standard HTTP and RESTful design, so any language that can send network requests works — including JavaScript (Node.js, Vue, React), Python, Java, PHP, Go, C#, and more. They fit web apps, mobile backends, mini-program cloud functions, automation scripts, and similar scenarios.

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