Validate Parse Script | Captain Docs

Validates a JavaScript parsing script without running it against real data. Upload your .js file as multipart/form-data. Checks that the script parses cleanly, exports a default function, and returns a string when called with an empty object.

The validation runs in the same sandboxed V8 engine used at indexing time, so a script that validates will work when you index files.

Returns HTTP 200 for both valid and invalid scripts - valid: false is a normal result, not an error.

Error Types

`error_type`	Meaning
`syntax_error`	JavaScript fails to parse
`no_export`	Script does not export a default function
`wrong_return_type`	Function returns something other than a string
`timeout`	Execution exceeded 5 seconds
`memory_exceeded`	Execution exceeded 32 MB heap

Validates a JavaScript parsing script without running it against real data. Upload your `.js` file as `multipart/form-data`. Checks that the script parses cleanly, exports a default function, and returns a string when called with an empty object. The validation runs in the same sandboxed V8 engine used at indexing time, so a script that validates will work when you index files. Returns HTTP 200 for both valid and invalid scripts - `valid: false` is a normal result, not an error. ### Error Types | `error_type` | Meaning | |---|---| | `syntax_error` | JavaScript fails to parse | | `no_export` | Script does not export a default function | | `wrong_return_type` | Function returns something other than a string | | `timeout` | Execution exceeded 5 seconds | | `memory_exceeded` | Execution exceeded 32 MB heap |

Authentication

AuthorizationBearer

Bearer token authentication using API key

Request

This endpoint expects a multipart form containing a file.

filefileRequired

The .js parsing script file to validate. Max 1 MB.

Response

Validation result. Returned for both valid AND invalid scripts.

validboolean

True if the script passes all validation checks.

errorstring or null

Human-readable error message. Null when valid=true.

error_typeenum or null

Error category. Null when valid=true.

Allowed values:

The validation runs in the same sandboxed V8 engine used at indexing time, so a script that validates will work when you index files.

Returns HTTP 200 for both valid and invalid scripts - valid: false is a normal result, not an error.

Error Types

`error_type`	Meaning
`syntax_error`	JavaScript fails to parse
`no_export`	Script does not export a default function
`wrong_return_type`	Function returns something other than a string
`timeout`	Execution exceeded 5 seconds
`memory_exceeded`	Execution exceeded 32 MB heap

1	import requests
2
3	BASE_URL = "https://api.runcaptain.com"
4	API_KEY = "your_api_key"
5	ORG_ID = "your_organization_id"
6
7	headers = {
8	"Authorization": f"Bearer {API_KEY}",
9	"X-Organization-ID": ORG_ID
10	}
11
12	# Upload a .js file from disk
13	with open("my-parser.js", "rb") as f:
14	response = requests.post(
15	f"{BASE_URL}/v2/parsing-scripts/validate",
16	headers=headers,
17	files={"file": ("my-parser.js", f, "application/javascript")},
18	timeout=30.0
19	)
20
21	result = response.json()
22	if result["valid"]:
23	print("Script is valid!")
24	else:
25	print(f"Error ({result['error_type']}): {result['error']}")

1	{
2	"valid": true
3	}

Error Types

Authentication

Headers

Request

Response

Error Types